Corrositex®:
An In Vitro Test Method for Assessing Dermal
Corrosivity Potential of Chemicals
The Results of an Independent Peer Review Evaluation
Coordinated by the Interagency Coordinating Committee on the
Validation of Alternative Methods (ICCVAM)
and theNational Toxicology Program (NTP) Interagency Center for the
Evaluation of Alternative Toxicological Methods (NICEATM)

National Toxicology Program
P.O. Box 12233
Research Triangle Park, NC 27709
June 1999
NIH Publication No. 99-4495

National Institute of Environmental Health Sciences
National Institutes of Health
US Public Health Service
Department of Health and Human ServicesiiiTable of Contents
List of Tables .................................................................................................................................. v
List of Abbreviations .................................................................................................................... vii
Peer Review Panel Members ......................................................................................................... ix
Acknowledgements ....................................................................................................................... xi
Preface ......................................................................................................................................... xv
Executive Summary ........................................................................................................................ 1
1.0 Test Method Description ......................................................................................................... 7
2.0 Test Method Data Quality ..................................................................................................... 15
3.0 Test Method Performance ..................................................................................................... 17
4.0 Test Method Reliability (Repeatability/Reproducibility) ...................................................... 29
5.0 Other Scientific Reviews ...................................................................................................... 33
6.0 Other Considerations ............................................................................................................. 37
7.0 Related Issues ........................................................................................................................ 41
8.0 Summary Conclusions and Recommendations ..................................................................... 43
References .................................................................................................................................... 49
AppendicesA. List of Chemicals Evaluated in Corrositex® ................................................................. A-1
B. Characterization of the Data Sources (Appendix A) Used for
Performance Analyses of Corrositex® ........................................................................... B-1
C. Corrositex® Test Method Submission (May, 1998) ....................................................... C-1
D. Corrositex® Instruction Manual ..................................................................................... D-1
E. NICEATM Comparison of the Corrositex® Instruction Manuals ................................. E-1

iii

Corrositex® Evaluation

Table of Contents

F. NICEATM List of Nonqualifying Chemicals for Corrositex® ....................................... F-1
G. NICEATM Evaluation of Nonqualifying Chemicals .................................................... G-1
H. NICEATM Table of Breakthrough Times for Chemicals Provided
by InVitro International, Inc. ......................................................................................... H-1
I. NICEATM Evaluation of the Performance of Corrositex® andthe pH Test ...................................................................................................................... I-1
J. NICEATM Description of the Data Set Used to Evaluate the®
Performance of Corrositex and the pH Test at Varying
pH Levels ....................................................................................................................... J-1
K. NICEATM Assessment of the Performance of Corrositex®
Compared to the Performance of the pH Test for Test Materials
in the Extreme pH Ranges ............................................................................................ K-1
L. NICEATM Summary of Results for Chemicals that Were Tested
in Both the Submission and the ECVAM Validation Study(Fentem et al., 1998) ..................................................................................................... L-1
M. NICEATM Evaluation of the Performance of Corrositex®
in Predicting Corrosivity/Noncorrosivity Compared to
In Vivo Findings ........................................................................................................... M-1
N. Quality Assurance Audit Summaries ............................................................................ N-1
O. Evaluation Guidance to the Peer Review Panel ............................................................ O-1
P. ICCVAM Validation and Regulatory Acceptance Criteria ............................................. P-1
Q. Guidelines and Regulations for Dermal Corrosivity..................................................... Q-1
R. Federal Register Notices ............................................................................................... R-1
S. Corrositex® Peer Review Meeting Agenda .................................................................... S-1
T. Corrositex® Peer Review Meeting Summary Minutes ................................................... T-1®

U. Summary of Public Comments on Corrositex ............................................................. U-1
V. ICCVAM Request to Forward the Corrositex® Report to Agencies
for Regulatory and Non-regulatory Acceptance Consideration .................................... V-1

iv

List of Tables
1.

Performance of Corrositex® by Chemical or Product Class .................................................. 4

2.

Comparison of Breakthrough Times for Acids as a Function ofConcentration ........................................................................................................................ 83.

In Vivo Reference Data for 17 Corrosive Chemicals Evaluated in the
ECVAM Validation Study (ECETOC, 1995) ...................................................................... 12

4.

Necrosis Observed in the Weil and Scala (1971) Study ...................................................... 13

5.

Evaluation of the Performance of Corrositex® in Predicting
Corrosivity/Noncorrosivity Compared to In Vivo Findings (Overall) ................................. 21

6.

Evaluation of the Performance of Corrositex® in Predicting
Corrosivity/Noncorrosivity Compared to In Vivo Findings(Inorganic and Organic Acids and Acid Mixtures) .............................................................. 21

7.

Evaluation of the Performance of Corrositex in Predicting
Corrosivity/Noncorrosivity Compared to In Vivo Findings(Acid Derivatives) ............................................................................................................... 23

8.

Evaluation of the Performance of Corrositex in Predicting
Corrosivity/Noncorrosivity Compared to In Vivo Findings(Amines) .............................................................................................................................. 23

9.

Evaluation of the Performance of Corrositex in Predicting
Corrosivity/Noncorrosivity Compared to In Vivo Findings(Inorganic Bases and Base Mixtures) .................................................................................. 24

10.

Evaluation of the Performance of Corrositex in Predicting
Corrosivity/Noncorrosivity Compared to In Vivo Findings(Inorganic and Organic Bases and Base Mixtures) ............................................................. 24

11.

Evaluation of the Performance of Corrositex in Predicting
Corrosivity/Noncorrosivity Compared to In Vivo Findings(Organic and Inorganic Acids and Bases) ........................................................................... 25

12.

Evaluation of the Performance of Corrositex in Predicting
Corrosivity/Noncorrosivity Compared to In Vivo Findings(Cleaners and Detergents) ................................................................................................... 25

®

®

®

®

®

®

v

Corrositex® Evaluation

List of Tables®

13.

Evaluation of the Performance of Corrositex in Predicting
Corrosivity/Noncorrosivity Compared to In Vivo Findings(Industrial Chemicals) ......................................................................................................... 27

14.

Evaluation of the Performance of Corrositex in Predicting
Corrosivity/Noncorrosivity Compared to In Vivo Findings(Surfactants) ......................................................................................................................... 27®

vi

List of Abbreviations
ANOVA
ATSDR
BAC
CDS
CFR
CPSC
CV
DOD
DOE
DOI
ECETOC
ECVAM
EG
FDA
FW
GLP
ICCVAM
IVI
NA
NaOH
NCI
NIEHS
NICEATM
NIH
NIOSH
NLM
NTP
OECD
OSHA
PRP
QAU
SAR
SD
SDS
SLS
SOP
Sponsor
Submission
TER
UK

Analysis of VarianceAgency for Toxic Substances and Disease Registry
N,N’-bis(acrylyl)cystamine
Chemical Detection System
Code of Federal Regulations
Consumer Product Safety Commission
Coefficient of Variation
Department of Defense
Department of Energy
Department of the Interior
European Centre for Ecotoxicology and Toxicology of Chemicals
European Centre for the Validation of Alternative Methods
Ethylene glycol
Food and Drug Administration
Formula Weight
Good Laboratory PracticeInteragency Coordinating Committee on the Validation of Alternative
Methods
InVitro International, Inc.
Not Applicable
Sodium Hydroxide
National Cancer InstituteNational Institute of Environmental Health Sciences
NTP Interagency Center for the Evaluation of Alternative Toxicological
Methods
National Institutes of HealthNational Institute for Occupational Safety and HealthNational Library of Medicine
National Toxicology Program
Organisation for Economic Co-Operation and Development
Occupational Safety and Health Administration
Peer Review Panel
Quality Assurance Unit
Structure-Activity Relationships
Standard Deviation
Sodium Dodecyl Sulfate
Sodium Lauryl Sulfate
Standard Operating Procedures
InVitro International, Inc.
Corrositex® Submission as provided by InVitro International, Inc.
Transcutaneous Electrical Resistance
United Kingdomvii

Corrositex® Evaluation

List of Abbreviations

UN
US
US DOT
US EPA

United Nations
United States
US Department of Transportation
US Environmental Protection Agency

viii

Peer Review Panel Members
Thefollowingindividuals
individuals
served on the Peer Review Panel that evaluated Corrositex® on
The following
served on the Peer Review Panel that evaluated the Corrositex ® assay
st
January
21 21st,, 1999on January
1999.
Ro bert Sca la, Ph.D., D.A.B.T., D.A.T.S . (Chair)

A. Walla ce Hayes, Ph.D ., D.A.B.T., D.A.T.S.

Rehoboth Beac h, DE

The Gillette Company
Boston, MA

J ames Chen, Ph.D.

K aren K ohrman, Ph.D.

N ational Cente r for Toxi cological Rese arch
Je ffe rson, AR

The Procter & Gamble Co.
Cincinnati, OH

Micha el J. Derelanko, Ph.D., D.A.B.T.

H ajime Kojima, Ph.D.

A llied-Signa l, Inc.
Morr istown, NJ

Nippon Menard Cosmetic Co., L td.
Nag oya, Japan

Ph.D., Executive(ExecutiveSecretary
Secretary)
Julia Fentem, Ph.D.,

Daniel Sauder, M.D.

U nilever Research Colworth
Bedf ordshire, United Kingdom

University of Toronto
Ontar io, Canada

Sidney G reen, Ph.D.

J ohn Stegeman, Ph.D.

H oward U nive rsity College of Medicine
Washington, DC

W oods Hole Oceanographic Institute
W oods Hole, MA

J ohn Harbell, Ph.D.
I nstitute for In Vitro Sciences
G aithersburg, MDix

xAcknowledgements
The followin g individ uals are acknowled ged for their contributions to the p eer review process .

Interagency Coordinating Committee on the Validation of Alternative M ethods(ICCVAM) Corrosi vity Working Group (CWG)
Agency for Toxic Substances andDisease Registry (ATSDR)

National Institute of Envi ronmental
Health Sciences (NIEHS)

W illiam Cibulas, Ph.D.
Buc k Grissom, Ph.D.

David Bridge
Joseph Hasema n, Ph. D.
William Stokes, D.V.M. (Co-Chair)
Errol Z eiger, Ph.D.

Consumer Product Safety Commission(CPSC)

National Institute for Occupational
Safety and Health (NIOSH)

Susan Aitken, Ph.D.
Kailash Gupta, Ph.D.
Marilyn Wind, Ph.D.

Doug Sharpnac k, D.V.M.

Departme nt of Defe nse (DOD)

National Library of Medicine (NLM)

John Frazier, Ph.D.
Harrold Salem, Ph.D.

Vera Hudson

Department of the Interior (DOI)

Occupational Safety and Heal thAdministration (OSHA)

Barnett Rattner, Ph.D.

Sure nder Ahir, Ph.D.

F ood and Drug Administration (FDA)US Department of Transportati on(US DOT)

June Brad law, Ph .D., Cen ter for Food
Safety and Applied Nutrition
Robe rt Bronaugh, Ph.D., Center for Food
Safety and Applied Nutrition
Ba rbara Hill, Ph.D., Cen ter for Drug
Evaluation and Research

James O’Steen
George Cushmac, Ph.D.
US Environmental P rotection Agency(US EP A)
Angela Auletta, Ph.D.
Oliver Fordam
Richard Hill, M.D., Ph.D . (Co-Ch air)
Leonard Keifer, Ph.D.
Mark Perr yJohn Re dden
Sheryl Reilly, Ph.D.
Yung Yang, Ph.D.

National Cancer Institute (NCI)
Victor Fung, Ph.D.
Davi d Longfellow, Ph.D.

xi

Corrositex® Evaluation

Acknowledgements

National Toxicology Program (NTP) Interagency Center for the
Evaluation of Alternative Toxicological Methods (NICEATM)
Loretta Brammell

Barry Margolin, Ph.D.

NIEHS

ILS, Inc.

Brigette Brevard, M.A.

Debbie McCarley

ILS, Inc.

NIEHS

Bonnie Carson,

M.S.

Kathy Miner

ILS, Inc.

ILS, Inc.

Thomas Goldsworthy, Ph.D.

William Stokes, D.V.M. (Director)

ILS, Inc.

NIEHS

Karen Haneke, M.S.

Raymond Tice, Ph.D.

ILS, Inc.

ILS, Inc.

Patrick Herron

Heather Vahdat

ILS, Inc.

ILS, Inc.

xii

Corrositex® Evaluation

Acknowledgements

Interagency Coordinating Committee on the Validation of Alternative
Methods (ICCVAM)
ATSDR

FDA (Continued)

William Cibulas, Ph.D.

Melvin Stratmeyer, Ph.D., Center for Devices andRadiological Health

CPSC

Neil L. Wilcox, D.V.M., M.P.H., Office of Science

Susan Aitken, Ph.D.
Kailash Gupta, Ph.D.
Marilyn Wind, Ph.D.

NCI

DOD

Victor A. Fung, Ph.D.
David Longfellow, Ph.D.

Robert Finch, Ph.D., U.S. Army Center for

NIEHS

Environmental Health Development Laboratory, Fort
Detrick Army BaseJohn M. Frazier, Ph.D., DOD Tri-Service Toxicology
Laboratory, Wright-Patterson Air Force Base
Harrold Salem, Ph.D., U.S. Army Edgewood Research,
Development and Engineering Center

John Bucher, Ph.D.
Rajendra Chhabra, Ph.D.
William Stokes, D.V.M. (Co-Chair)
Errol Zeiger, Ph.D.
NIH, Office of the Director

Department of Energy (DOE)

Christina Blakeslee
Louis Sibal, Ph.D.

Marvin Frazier, Ph.D.

NIOSH

DOI
Barnett A. Rattner, Ph.D.

Douglas Sharpnack, D.V.M.
Kenneth Weber, Ph.D.

FDA

NLM
Vera Hudson

William T. Allaben, Ph.D., National Center for

OSHA

Toxicological Research

Joseph F. Contrera, Ph.D., Center for Drug Evaluation
and Research

Joseph DeGeorge, Ph.D., Center for Drug Evaluation
and Research

Surender Ahir, Ph.D.
US DOT
George Cushmac, Ph.D.
James K. O’Steen

Larry D’Hoostelaere, Ph.D., Office of Regulatory
Affairs

US EPADavid G. Hattan, Ph.D., Center for Food Safety andApplied Nutrition

Angela Auletta, Ph.D., Office of Prevention,

Raju Kammula, Ph.D., Center for Devices andPesticides, and Toxic SubstancesRadiological Health

Karen Hamernik, Ph.D., Office of Prevention,

Anita O’Connor, Ph.D., Office of Science
Anne M. Pilaro, Ph.D., Center for Biologics

Richard Hill, M.D., Ph.D. (Co-Chair)

Evaluation and Research
Neil Sass, Ph.D., Center for Food Safety and Applied
Nutrition
Leonard M. Schechtman, Ph.D., Center for Drug
Evaluation and Research

Office of Prevention, Pesticides, and Toxic
Substances
Hugh Tilson, Ph.D., National Health andEnvironmental Effects Research/Office of Researchand Development

Pesticides, and Toxic Substances

xiii

xiv

Preface
The Interagency Coordinating Committee on the
Validation of Alternative Methods (ICCVAM)
with support from the National Toxicology Pro­
gram (NTP) Interagency Center for the Evalu­
ation of Alternative Toxicological Methods(NICEATM) recently sponsored the indepen­
dent scientific peer review of Corrositex®, a new
test method proposed for assessing the dermal
corrosivity potential of chemicals. Such reviews
are critical components in the ICCVAM pro­
cess that culminates in achieving regulatory
acceptance and implementation of new scien­tifically validated toxicological testing methods.
These methods are generally more predictiveof adverse human health effects than current
methods, and they may be alternative methods
that provide for improved animal well-being,that use phylogenetically lower species, or that
reduce or eliminate the need for animals. The
peer review was conducted in accordance withpublic health directives of Public Law 103-43,
which directed the National Institute of Envi­ronmental Health Sciences (NIEHS) to develop
and validate improved alternative toxicologicaltesting methods, and to develop a process forthe regulatory acceptance of such methods (see:Validation and Regulatory Acceptance of Toxi­
cological Test Methods: A Report of the Ad HocInteragency Coordinating Committee on the
Validation of Alternative Methods, NIH publi­
cation 97-3981; http://ntp-server.niehs.nih.gov/
htdocs/ICCVAM/iccvam.html).

lowing Federal regulatory and research agen­cies and organizations are participating in thiseffort:Consumer Product Safety Commission
Department of Defense
Department of Energy
Department of Health and Human Services
Agency for Toxic Substances andDisease Registry
Food and Drug Administration
National Institute for Occupational
Safety and Health/Centers for
Disease Control
National Institutes of HealthNational Cancer InstituteNational Institute of Environmental
Health Sciences
National Library of Medicine
Department of the Interior
Department of Labor
Occupational Safety and HealthAdministration
Department of Transportation
Research and Special Programs
Administration
Environmental Protection Agency
Corrositex ® was proposed to ICCVAM by
InVitro International, Inc. (IVI, Sponsor), as anin vitro alternative test method to in vivo meth­ods for assessing the potential of chemicals tocause skin corrosion. NICEATM and an
ICCVAM Corrosivity Working Group (CWG)
composed of Federal employees, through inter­actions with the Sponsor, requested and as­
sembled information for an independent scien­tific peer review of the method. Suggested ex­
perts for the peer review panel (PRP) were so­licited from Federal agencies and national andinternational professional societies and organi­zations. The CWG recommended a panel com­position that would represent a broad range ofexperience and expertise, including general andin vitro toxicology, clinical dermatology, and

The ICCVAM was established as a standing
collaborative effort by NIEHS and 13 otherregulatory and research agencies and programs.
ICCVAM coordinates issues within the Federal
government that relate to the development, vali­
dation, acceptance, and national/international
harmonization of toxicological test methods.
The Committee’s functions include the coordi­
nation of interagency scientific reviews of toxi­
cological test methods and communication withstakeholders throughout the process of test
method development and validation. The fol­xv

Corrositex® Evaluation

Prefacebiostatistics. PRP members were from indus­
try, academia, and government, and included
scientists from the United States (US), Canada,
Japan, and the United Kingdom (UK).

evaluations, conclusions, and recommendations
were consolidated into the PRP Report, which
follows. The PRP concurred in a public meet­ing via teleconference on April 22, 1999, that
the Report accurately reflects the conclusions
and recommendations of the January 21 meet­ing. Additional data analyses prepared for the
PRP by NICEATM and the test method submis­
sion are also included as appendices in this docu­
ment.

The PRP was charged with developing a scien­tific consensus on the usefulness and limitationsof Corrositex® for assessing the skin corrosivity
potential of chemicals. In reaching this deter­
mination, the PRP was requested to evaluate allavailable information and data on the
Corrositex® assay, and to assess the extent towhich each of the criteria for validation andregulatory acceptance developed in the
ICCVAM Report were addressed. The PRP wasprovided with guidance for their evaluation,
which included questions from the CWG toensure that the assessment provided adequate
information to facilitate ICCVAM and agency
decisions on the method.

Following the peer review meeting, the CWG
reviewed the PRP Report, and provided recom­
mendations to ICCVAM. This entire report has
been reviewed and endorsed by the CWG and
ICCVAM. The Report, along with recommen­
dations on the usefulness of the method, will be
forwarded by ICCVAM to Federal agencies fortheir consideration. Agencies will determine theregulatory acceptability and applicability of thismethod according to their statutory mandates,
and as deemed appropriate, issue guidelines,
guidance documents, or proposed changes inregulations.

A request for information regarding the use­
fulness of the Corrositex® assay, including in­formation about completed, ongoing, orplanned studies and other data was made via aFederal Register notice (July 28, 1998, Vol.
63, No. 144, 40303.) The availability of thetest method submission materials, a request for
public comments, and the planned public peer
review meeting were announced in October,1998 (Federal Register, October 27, 1998, Vol.
63, No. 207, page 57303). All comments andinformation submitted in response to the re­quests and announcements were provided to
the PRP in advance of the review meeting.

The work of the PRP was truly a team effort,
and their thoughtful and unselfish contributions
are gratefully acknowledged. While all mem­bers contributed to this evaluation, the excep­
tional efforts of Dr. Robert Scala, who served
as the PRP chair, deserves special recognition.
The efforts of the CWG were instrumental inassuring a meaningful and comprehensive re­view that would address regulatory needs, andfor evaluation of the recommendations of the
PRP. Finally, the efforts of the NICEATM staff
to ensure accurate analyses and timely distri­bution of information for the review are ac­knowledged, particularly the efforts of Dr.
Thomas Goldsworthy, Dr. Raymond Tice, and
Ms. Karen Haneke. On behalf of ICCVAM, we
thank the many individuals who contributed tothis report.

The PRP met in public session on January 21,
1999, at the National Institutes of Health (NIH)
Natcher Conference Center in Bethesda, Mary­land. During the meeting, PRP members pre­sented their evaluations and proposed conclu­
sions and recommendations on each of the ma­
jor sections and the PRP subsequently reacheda consensus for each section. The opportunity
for public comment was provided during themeeting. Following the meeting, the written

William S. Stokes, Co-Chair, ICCVAM
Richard N. Hill, Co-Chair, ICCVAM
xvi

EXECUTIVE SUMMARY
Methods (ICCVAM) received a Corrositex®
Submission (Submission) from InVitro Interna­
tional, Inc. (IVI, Sponsor) for peer review. The
Submission included additional information
requested by ICCVAM following previous com­munications between ICCVAM and IVI.
ICCVAM determined that the Submission was
sufficiently complete to undergo peer review.
An independent Peer Review Panel (PRP) was
assembled to evaluate the extent to which eachof the ICCVAM validation and acceptance cri­
teria had been addressed, and to determine theusefulness and limitations of Corrositex® for theidentification of potential human corrosive
chemicals or chemical mixtures.

Corrosive substances are defined as chemicals
that cause visible destruction of, or irreversible
alterations in, living tissue by chemical action
at the site of contact (29 CFR [Code of Federal
Regulations] 1917.28, 1998). Dermal
corrosivity testing is conducted to identify
chemicals that potentially pose this hazard tohumans. Test results are used to classify andlabel chemicals with regard to this potential
hazard so that consumers and workers can takeappropriate precautions to prevent injury. Test
results are also used to determine appropriate
packaging that will minimize hazardous spills
during transport. US Federal agencies that haveregulations related to corrosivity testing include
the Consumer Product Safety Commission(CPSC), Occupational Safety and Health Ad­
ministration (OSHA), US Department of Trans­
portation (US DOT), and the Environmental
Protection Agency (EPA) (Appendix Q). Regu­
lations and guidelines include testing methods
for assessing dermal corrosivity, appropriate
chemical packaging and labeling, appropriate
transport and/or storage methods, and aware­ness education programs for workers in indus­
trial settings.

The PRP evaluation of the Corrositex® Submis­
sion addressed seven topics, with two to five
PRP members assigned as primary reviewers
for each topic. This report is organized by these
topics, as follows: (1) Test Method Descrip­
tion; (2) Test Method Data Quality; (3) Test
Method Performance; (4) Test Method Reliabil­ity (Repeatability/Reproducibility); (5) Other
Scientific Reviews; (6) Other Considerations;and (7) Related Issues. Thesetopics are followed
by a Summary Conclusions and Recommenda­
tions section. This report focuses on the per­formance of Corrositex® as compared to the invivo rabbit skin corrosivity test. The validity of
the in vivo rabbit skin corrosivity test was notevaluated.

For regulatory purposes, identification of cor­rosive chemicals and chemical mixtures has
been based on the ability of a chemical or chemi­
cal mixture to produce visible destruction or ir­
reversible alterations of the skin at the site ofcontact. The commonly used in vivo test method
involves application of chemicals or chemical
mixtures on the intact skin of a rabbit. The skinis visually evaluated for corrosion within threeminutes, and at one or four hours after applica­tion. Animal welfare considerations have led
to efforts to develop in vitro alternative test
methods.

Corrositex® is an in vitro method used to deter­mine the dermal corrosive potential of chemi­cals and chemical mixtures. Corrositex® isbased on the ability of a corrosive chemical orchemical mixture to pass through, by diffusion
and/or destruction/erosion, a biobarrier and toelicit a color change in the underlying liquid
Chemical Detection System (CDS). The
biobarrier is composed of a hydrated collagenmatrix in a supporting filter membrane, while

In May 1998, the Interagency Coordinating
Committee on the Validation of Alternative17

Corrositex® Evaluation

Executive Summary

the usefulness of Corrositex® for assessing thecorrosivity potential of chemicals or chemical
mixtures. The PRP addressed the following two
major questions:the CDS is composed of water and pH indica­
tor dyes. Test chemicals and chemical mixtures,
including solids and liquids, are applied directly
to the biobarrier. The time it takes for a test
chemical or chemical mixture to penetrate thebiobarrier and produce a color change in the
CDS is compared to a classification chart todetermine corrosivity/noncorrosivity and to
identify the appropriate US DOT packing group.
Chemicals are prescreened for compatibility
with the assay by directly applying the test
chemical or chemical mixture to the CDS; if acolor change is not induced, then the test chemi­
cal or chemical mixture does not qualify for test­
ing with this assay. The US DOT currently ac­
cepts the use of Corrositex® to assign subcat­
egories of corrosivity (packing groups) for la­
beling purposes according to United Nations(UN) Committee of Experts on the Transportof Dangerous Goods guidelines. However, the
US DOT limits the use of Corrositex® to spe­cific chemical classes, including acids, acid de­rivatives, acyl halides, alkylamines andpolyalkylamines, bases, chlorosilanes, metal
halides, and oxyhalides (Appendix Q).

1.

Has Corrositex® been evaluated sufficiently
and is its performance satisfactory to sup­port its proposed use for assessing thecorrosivity potential of chemicals or chemi­
cal mixtures?

2.

Does Corrositex® offer advantages withrespect to animal welfare considerations(refinement 1, reduction2, and replacement3
alternatives)?

In response to the first question, Corrositex®
performance indicates that, in specific testing
circumstances such as that required by US DOT,
Corrositex® is useful as a stand-alone assay forevaluating the corrosivity or noncorrosivity ofacids, bases, and acid derivatives. The current
US DOT exemption allows the use ofCorrositex® for assigning packing groups foracids, acid derivatives, acyl halides, alkylaminesand polyalkylamines, bases, chlorosilanes,
metal halides, and oxyhalides. However, theCorrositex® database evaluated by the PRP did
not include acyl halides, chlorosilanes, metal
halides, or oxyhalides; thus no statement wasmade by the PRP for these chemical classes. In
other testing circumstances, and for other chemi­
cal and product classes, Corrositex® may be usedas part of a tiered assessment strategy. In thisapproach, negative responses must be followed

The database used in this evaluation consistedof Corrositex ® data on 163 chemicals andchemical mixtures for which there were corre­
sponding in vivo rabbit corrosivity data. Dataon 118 chemicals and chemical mixtures were
provided by IVI, while data on an additional 45
chemicals and chemical mixtures were obtained
from two peer-reviewed publications that evalu­
ated the validity of Corrositex® (Botham et al.,
1995; Fentem et al., 1998). These two studies
involved a total of 77 chemicals and chemical
mixtures, of which 32 chemicals and chemical
mixtures were also included in the IVI Submis­
sion.

1

Refinement alternative: A new or revised test methodthat refines procedures to lessen or eliminate pain or dis­tress to animals, or enhances animal well-being (NIEHS,
1997).
2
Reduction alternative: A new or revised test method that
reduces the number of animals required (NIEHS, 1997).
3
Replacement alternative: A new or revised test methodthat replaces animals with non-animal systems or one
animal species with a phylogenetically lower one(NIEHS, 1997).

A public meeting of the PRP took place on Janu­ary 21, 1999, in Bethesda, MD, to reach con­clusions and make recommendations regarding18

Corrositex® Evaluation

Executive Summary

data quality and credibility. Positive and nega­tive control values should be reported concur­
rently with each assay to demonstrate that thetest is working properly.

by dermal irritation testing, and positive re­sponses require no further testing unless the in­vestigator is concerned about potential false
positive responses. In either testing strategy,
an investigator may conclude that confirmation
testing is necessary based on consideration of
supplemental information, such as pH, struc­ture-activity relationships, and other chemical
and/or testing information. As additional test
results with Corrositex® are obtained, the util­
ity of the assay may need to be reconsidered.
Corrositex® is limited in its universal utility
because of the proportion of chemicals that are
not compatible with the CDS and thus cannot
be evaluated.

The PRP also suggested that laboratories unfa­
miliar with conducting the test should obtainappropriate training and conduct tests with test
reference chemicals before undertaking any test­
ing of unknown chemicals and chemical mix­tures.
Given the ease and cost effectiveness of con­ducting a pH test, the PRP recommended that
pH testing be conducted prior to use ofCorrositex®. Such information could be usedin the future to re-evaluate the agreement be­
tween pH and Corrositex ® in identifying
corrosivity.

The following specific changes to the protocol
were recommended:(1)

It should be explicitly stated that thebiobarrier should be allowed to harden
on a level surface and to cool overnight
before use.

(2)

Even though replicate variability has
been shown to be very low, guidanceshould be provided on how to evaluate
an aberrant value.

(3)

The IVI Corrositex® Data Sheets pro­vided with the test kit should contain aprovision for recording the performanceof the positive and negative controls.
This information should be used to de­termine the suitability of the test results.
Description of the test protocol would
benefit from the addition of a flow dia­gram illustrating the steps in the proce­
dure.

(4)

Compared to in vivo rabbit skin corrosivity test
results, Corrositex® had an overall sensitivity4of 85% (76/89), specificity5 of 70% (52/74), andaccuracy6 of 79% (128/163) for the chemicals
and chemical mixtures evaluated. The three data
sets reviewed (Submission [Appendix D];
Botham et al., 1995; Fentem et al., 1998) gen­erally showed a similar degree of sensitivity,
specificity, and accuracy.
The sensitivity, specificity, and accuracy ofCorrositex® by chemical or product class areprovided in Table 1.
The PRP concluded that the protocol suppliedby IVI for conducting Corrositex® was complete
and provided the necessary details for a user to4

Sensitivity is defined as the proportion of all positive
chemicals or chemical mixtures that are correctly classi­
fied as positive in a test (NIEHS, 1997).
5
Specificity is defined as the proportion of all negative
chemicals or chemical mixtures that are correctly classi­
fied as negative in a test (NIEHS, 1997).
6
Accuracy (concordance) is defined as the proportion ofcorrect outcomes of a method (NIEHS, 1997)

In future studies, compliance with Good Labo­ratory Practice (GLP) Guidelines and inclusionof quality control procedures, would improve19

Corrositex® Evaluation

Executive Summary

Table 1. Performance of Corrositex® by Chemical or Product Class
Chemical/Product Class

Sensitivity

Specificity

Accuracy

Overall

85% (76/89)

70% (52/74)

79% (128/163)

Inorganic and organic acids plus acid mixtures

79% (22/28)

63% (5/8)

75% (27/36)

Acid derivatives

100% (7/7)

86% (6/7)

93% (13/14)

Amines84% (16/19)

67% (4/6)

80% (20/25)

Inorganic and organic bases plus base mixtures

89% (25/28)

57% (4/7)

83% (29/35)

Organic and inorganic acids and bases

86% (54/63)

68% (15/22)

81% (69/85)

Cleaners and detergents

90% (9/10)

29% (4/14)

54% (13/24)

Undefined industrial Chemicals

87% (13/15)

62% (8/13)

75% (21/28)*

100% (22/22)

100% (22/22)

Surfactants

The numbers in parentheses provide the data on which the percentages are based.
*No corrosive surfactants tested.

positive and negative controls to determine
whether each test trial is performing correctly;
no controls are included in the in vivo assay,
which limits an assessment of precision7.

conduct the assay correctly. The transferabilityof the method between laboratories and the sim­
plicity of the assay were considered to be at­
tractive features of Corrositex®. Similarly,
methods for data analysis and the decision cri­
teria were straightforward. Instructions on how
to convert the breakthrough time to the deter­
mination of corrosivity were considered to becomprehensive and easy to follow.

A limitation of the method is that many noncor­
rosive chemicals and chemical mixtures andsome corrosive chemicals and chemical mix­tures do not qualify for testing by Corrositex®.
Test chemicals and chemical mixtures are con­sidered nonqualifying if they do not cause acolor change in the CDS; the CDS changes color
when a chemical or chemical mixture changes
the pH of the solution to less than 5 or greaterthan 8.5. The majority of nonqualifying chemi­cals and chemical mixtures (49 of 50) in the
IVI and Validation Study (Botham et al., 1995;
Fentem et al., 1998) database for which pH data
were also available had a pH between three and

The PRP concluded that an attractive feature ofCorrositex® is that no animals are used. In ad­
dition, the test is rapid and less expensive thanthe comparable rabbit corrosivity test (see Sec­tion 6.2). In addition to the available informa­tion on inter- and intra-laboratory variability, thein vitro nature of the test allows for the devel­
opment of an expanded database on coded com­pounds tested over time and in several labora­
tories to provide additional information on in­ter- and intra-laboratory variability in assay re­sponse. No such formal studies have been con­ducted with the in vivo rabbit corrosivity test.
Additionally, Corrositex® includes concurrent

7

Precision is defined as the extent to which a measure­ment procedure gives the same results when repeatedunder identical conditions; the inverse of variance(Dorland’s Illustrated Medical Dictionary, 1994)

20

Corrositex® Evaluation

Executive Summary

The PRP concluded that a limitation in theevaluation of the Corrositex® database was therelatively small number of chemicals and/or theunbalanced distribution of corrosive and non­corrosive chemicals and chemical mixtures
evaluated in some chemical/product classes. As
a consequence, accurate conclusions about theperformance of Corrositex® for some chemicalclasses could not be made.

ten. Of the 75 nonqualifying chemicals andchemical mixtures in the database for which invivo data were available, 85% (64/75) were clas­sified as noncorrosive in the in vivo test8. The
remaining 11 of 75 nonqualifying chemicals andchemical mixtures (15%) were classified as
corrosive in the in vivo test. Thus, it appears
that the qualification step eliminates primarily
chemicals that are noncorrosive. Other in vitro
methods (e.g., rat skin transcutaneous electri­
cal resistance [TER] and EPISKIN TM) for
corrosivity have not shown this same limitation(Fentem et al., 1998).

In response to the second question, the PRP
concluded that Corrositex® offers several advan­
tages with respect to animal welfare consider­ations, including refinement, reduction, and re­placement of animal use. Corrositex®, whenused as a stand-alone assay in some testing situ­
ations, replaces the use of animals for corrosivity
testing. Similarly, the use of Corrositex® as partof a tiered approach reduces and refines the useof animals in testing by providing a basis for
decisions on further testing. Follow-up tests
using in vivo methods, when deemed necessary,
could employ fewer animals and test agent di­lution schemes to minimize possible pain in any
individual animal.

Information on the composition of the complex
mixtures (generally industrial chemicals, clean­ers and detergents, and surfactants) tested us­
ing Corrositex® and the in vivo rabbit skin as­
say was not available. The accuracy was 54%(13/24) for cleaners and detergents, 75% (21/28) for unspecified industrial chemicals, and100% (22/22) for surfactants. However, the PRP
did not consider it appropriate to reach conclu­
sions on the usefulness of Corrositex® for theseproduct classes without knowing the composi­tion of these materials.

8

In some instances, this analysis includes results fromseveral concentrations of the same chemical.

21

22

1.0 TEST METHOD DESCRIPTION
1.1

Sufficiency of test method andprotocol description

1.1.1

Adequacy and completeness of the test
methoddiffusion through the collagen matrix and, withtime, even noncorrosive chemicals and chemi­
cal mixtures will reach the CDS. For that rea­son, four hours is used as the upper limit for theassay. Some Category 19 noncorrosive chemi­cals and chemical mixtures (e.g.,dithiopropionic acid) react with the CDS, yet
the chemical or chemical mixture does not reach
the CDS within the required four hours of ex­
posure. The Submission contains data on the
breakthrough times for various chemicals andchemical mixtures at different concentrations.
When the breakthrough times for acetic (FW[Formula Weight] 60.5), propionic (FW 74),butyric (FW 88), and citric (FW 192) acids as afunction of molar concentration are compared,
very different breakthrough times are observed(Table 2). These data suggest that the interac­tion between a weak acid and the biobarrier ismore complex than simple diffusion.

The Submission contained a thorough protocol.
The scientific and empirical basis of the test was
described in sufficient detail. Corrositex® mea­sures the time required for a chemical or chemi­
cal mixture to pass through a hydrated collagenmatrix (biobarrier) and supporting filter mem­brane. Passage through the biobarrier
is observed by a color change in the CDS, an
underlying aqueous solution of two pH indica­
tor dyes. The time required to pass through thebiobarrier, referred to as the breakthrough time,
is used as a measure of the corrosive potentialof the chemical or chemical mixture under test.
The Sponsors propose that the time required topass through the biobarrier depends on: (1) thestrength of the acid or base; (2) the rate of dif­fusion of the test chemical or chemical mixture;and (3) for more corrosive substances, the rateof destruction of the biobarrier. However, one
member of the PRP noted that the compositionof the biobarrier, which is IVI proprietary in­formation, could not be compared directly withskin.

Corrositex® is correlative in nature, rather thanmechanistic. The matrix was engineered toblock passage of certain chemicals and chemi­
cal mixtures for a period of time similar to thetime allowed for that chemical or chemical mix­
ture to stay in contact with rabbit skin withoutcausing “necrosis or ulceration.” However,while an acellular matrix might ulcerate, it can­not undergo necrosis.

The destruction/erosion of the biobarrier is eas­
ily observed with strong acids and bases. IVI
suggests that the breakthrough time for diluteacids or bases depends on diffusion through thebiobarrier, rather than on destruction of thebiobarrier itself. However, if the assay were
simply measuring the rate of diffusion of thechemical or chemical mixture through thebiobarrier, noncorrosive chemicals and chemi­
cal mixtures (e.g., buffered solutions of organic
acids) would be expected to diffuse through thebiobarrier, on a molar basis, as quickly as un­
buffered mild corrosives. Certainly, there is

In the Submission, the range of applications (i.e.,
types of test chemicals and chemical mixtures)
was insufficiently described. The Sponsors pro­
9

The instruction manual provides instructions for deter­mining the category (1 or 2) of a material based on the
degree of color change observed in the qualification step,which is indicative of the degree of the acid/alkaline re­serve. This categorization determines the cut-off times
used to determine the corrosivity/noncorrosivity of asample. See the Corrositex® Instruction Manual in Ap­
pendix D for a complete description of this determina­
tion.

23

Corrositex® Evaluation

Test Method Description

Table 2. Comparison of Breakthrough Times for Acids as a Function of Concentration
Acid

Concentration(M)

BreakthroughTime (min)Lowest Concentration (M)Yielding Breakthrough in Less
than 60 Min.

BreakthroughTime (min)Acetic

0.50

53

0.50

53

Propionic

0.54

86

1.35

59

Butyric

0.57

88

11.24

56

Citric

0.52

66

0.76

59

posed that Corrositex® is comparable to the invivo rabbit skin corrosivity test with regard toits ability to assess the corrosivity of welldefined inorganic and organic acids and bases,
and complex mixtures of inorganic and organic
acids and bases. The Sponsors also stated thatthe test was suitable for assessing US DOT Class
8 corrosive materials, which are defined either
as liquids or solids that cause full thickness de­
struction of human skin at the site of contact
within a specified period of time, or as liquids
that have a severe corrosion rate on steel or alu­
minum based on specified criteria (Appendix
Q). However, the Submission does not address
such broad applicability. For example, thechlorosilanes are not represented in the provided
database. In general, the chemical/productclasses as defined in the Submission are broadand generic (e.g., amines and acid derivatives).
It would have been useful if the chemical andproduct classes were more specific. Amines
could have been classified as primary, second­ary, or tertiary, and acid derivatives could havebeen classified as anhydrides, haloacids, salts,
etc., as appropriate. For the database evaluated,
all test chemicals and chemical mixtures wereassigned to the same chemical or product classes
used in the Submission. The categories wereas follows: inorganic and organic acids, acidmixtures, acid derivatives, amines, inorganic
bases, base mixtures, cleaners, detergents, un­defined industrial chemicals, and surfactants. It
was not possible to determine whether chemi­cals and chemical mixtures tested in each chemi­

cal or product class are representative of thevariety of chemicals in that class.
1.1.2

Adequacy of agreement between thevalidation protocol and proposed pro­tocol

The protocol used to generate the supporting
Submission data is consistent with the protocol
currently proposed by IVI. Only three differ­ences were noted. First, the stability limit of
the biobarrier was changed from ten to sevendays. Second, the time for classification of
Category 2 chemicals and chemical mixtures for
Packing Group III10 was changed from “greaterthan 30 to 45 minutes” to “greater than 30 to 60
minutes.” Third, the Corrositex® cut-off time
for Category 2 noncorrosive chemicals andchemical mixtures was increased from greaterthan 45 minutes to greater than 60 minutes. The
impact, if any, of the first change is not known.
10

US DOT assigns packing groups to corrosives basedon the severity of the corrosive response. Packing Group
I corrosives are defined as materials that cause full thick­ness destruction of intact skin tissue within an observa­
tion period of up to 60 minutes starting after the expo­
sure time of three minutes or less. Packing Group II cor­rosives are materials not meeting Packing Group I crite­
ria and causing full thickness destruction of intact skintissue within 14 days after an exposure time of more than
three minutes but less than 60 minutes. Packing GroupIII corrosives are materials not meeting Packing Group I
or II criteria but causing full thickness destruction of in­tact skin tissue within 14 days after an exposure time ofmore than 60 minutes but less than four hours (49 CFR
173.137).

24

Corrositex® Evaluation

Test Method Description

The other changes were mandated by US DOT
in granting the second exemption (US DOT,
1996). The data provided in the current Sub­mission are based on the revised cut-off times
for Category 2 chemicals and chemical mix­tures. The two latter changes do not affect theperformance evaluation of Corrositex® versus
the in vivo corrosivity test.

were based on an extensive evaluation of cor­rosive and noncorrosive chemicals and chemi­
cal mixtures and of knowledge gained throughthe Prevalidation and Validation Studies(Botham et al., 1995; Fentem et al., 1998). The
rate of false positive and false negative re­sponses for various chemical classes suggests
some value in attempting to further refine thedose and breakthrough times if the assay is to
be used as a stand-alone assay for additional
chemical classes.

The Corrositex ® protocol used in thePrevalidation Study (Botham et al., 1995) andEuropean Centre for the Validation of Alterna­
tive Methods (ECVAM) Validation Study(Fentem et al., 1998) was similar to the one usedby IVI, with three exceptions. First, the IVI
protocol required that the biobarrier be refrig­
erated for a minimum of two hours prior to use,
while the protocol for both validation studies
required an overnight cooling period. The
longer cooling period was used to decrease
breakthrough time variability when sodium hy­
droxide (NaOH) pellets were used as the posi­tive control. Second, the positive and negative
controls differed between the IVI and the twovalidation study protocols. The validation study
protocols used a positive control consisting ofa single pellet of NaOH and a “blank” as a nega­tive control. The IVI protocol suggests the useof 68 to 73% nitric acid or 95 to 98% sulfuric
acid as a positive control, and 10% citric acidor 6% propionic acid as a negative control.
Third, the Prevalidation Study protocol did notinclude the categorization step used in the IVI
and the ECVAM Validation Study protocols.
The categorization step is used to enable a test
chemical to be measured against a revised scor­
ing scale, based on the acid/alkaline reserve of
the sample. No impact on the quality of thedata is expected based on these differences.
1.1.3

The amount of test chemical or chemical mix­
ture used in Corrositex® is the same as that speci­
fied for the rabbit studies, although rationale forthis dose selection in Corrositex® was not con­sidered by the PRP. However, the ratio of test
chemical or chemical mixture to unit area ofthe biobarrier (0.5 g or 0.5 mL to 0.71 cm2) ex­
ceeds the expected ratio of test chemical orchemical mixture to skin area in the rabbit study
by 8.5-fold.
Selection of the maximum exposure time andinterpretation of the breakthrough time are basedon the categorization screen (Category 1 or 2).
The categorization screen determinations are
reproducible within and across laboratories. In
the ECVAM Validation Study (Fentem et al.,1998), 60 chemicals were evaluated by threelaboratories in two independent trials. Of the
40 chemicals that qualified, the categorization
screen results were in disagreement among thelaboratories only twice. Thus, this aspect of theassay seems appropriate.
The qualification test with the CDS provides anumber of benefits to the assay. It immediately
eliminates those chemicals and chemical mix­tures that cannot be evaluated using Corrositex®
and it provides the operator with a clear indica­tion of the expected color change that the test
chemical or chemical mixture would induce
upon breakthrough of the biobarrier.

Appropriateness of dose and break­through time selection procedure

The dose and breakthrough time selection pro­cedures were considered to be appropriate. Both
25

Corrositex® Evaluation

Test Method Description

1.2

Adequacy and completeness of thetest method protocol

1.2.1

Test method material and equipment,
animal usage

mixture to the biobarrier. In addition, the break­through time(s) of the positive and negative
controls would be recorded for each trial. The
usual ancillary data associated with any assay(test article identification, number, descriptions,
lot numbers, etc.) would also be recorded. The
time required to breakthrough the biobarrier isused to determine whether the test chemical orchemical mixture would be classified as a cor­rosive according to the cut-off times provided
in the appropriate category table.

The protocol for the assay is complete and pro­vides the necessary detail for the user to apply
the assay correctly. The manual gives a detailed
description of the steps to conduct the assay,
the materials and equipment needed, and spe­cial precautions for ensuring a successful test.
The transferability of the method between labo­
ratories, as defined by the low interlaboratory
variability in the validation studies (Botham etal., 1995; Fentem et al., 1998), supports the con­clusion that the manual provides sufficient de­
tail. No animal use is involved.

A topic that is not discussed in the protocol orin the Submission is the acceptable variability
among replicate tests for the same chemical orchemical mixture (i.e., expected coefficient ofvariation). While the results of the validation
studies (Botham et al., 1995; Fentem et al.,1998) suggest that the replicate determinations
are very close, guidance on how to evaluate anaberrant value would be valuable.

Additional detail to the IVI protocol, such asallowing the biobarrier to harden on a level sur­face, may be useful in helping to eliminate po­tential sources of error. This type of informa­tion was provided previously by IVI technicalservice personnel. Such additions to the proto­
col would not alter its fundamental properties.
1.2.2

1.2.3

Data analysis, evaluation, and decision
criteria

The descriptions of data collection, data evalu­
ation, and the decision criteria used to identify
chemicals and chemical mixtures as qualifying
or nonqualifying, Category 1 or 2, and corro­
sive or noncorrosive are well documented. The
performance of the qualification test with the
CDS is well described, and the prescreen pre­pares the operator for the color change that will
occur in the CDS when the chemical or chemi­
cal mixture is tested. As the color change canbe subtle, there is the potential for operator sub­jectivity. Such differences were sporadically
noted in the ECVAM Validation Study (Fentem
et al., 1998). The categorization screen is well
documented and the manufacturer provides suf­
ficient color plates to facilitate interpretation.
Instructions on how to convert the breakthroughtime to the determination of corrosivity are com­plete and easy to comprehend. The protocol
also includes information on how to make a

Data collection

Submission information on the test method
clearly stated that data sheets are included in
the test kit, along with instructions on what is
to be measured and how the data are to be inter­
preted. The simplicity of the procedure is oneof the attractive features of Corrositex®. The
same may be said of the data analysis and deci­sion criteria. At least three types of experimen­
tal data are collected on each chemical or chemi­
cal mixture tested: (1) the presence or absenceof a color change in the CDS in the qualifica­tion screen; (2) the presence or absence of acolor change in the categorization screen; and(3) the time required, up to the limits of the ex­posure time, to induce a color change in the CDS
after addition of the test chemical or chemical
26

Corrositex® Evaluation

Test Method Description

decision when the breakthrough values are very
close to the cut-off between classes.
1.2.4(Botham et al., 1995; Fentem et al., 1998), a
NaOH pellet was used as a positive control
based on the desire to have a breakthrough timein the Packing Group II category. This allowed
for readily observable differences in break­through times. The addition of a true negative
control to the protocol by IVI is an excellent
amendment. A chemical or chemical mixture
that has a breakthrough time closer to the cut­
off of 60 minutes might be more appropriate,
or it might be useful to extend the duration of
the assay to determine a breakthrough time forthe concurrent negative control. In the Submis­
sion, the discussion of controls applies only to
Corrositex® since the current in vivo assays do
not include controls.

Number of replicates per test article

The Prevalidation and ECVAM Validation Stud­ies (Botham et al., 1995; Fentem et al., 1998)
found a lack of appreciable variability in thereplicate data. The Corrositex® Instruction
Manual (Appendix D) recommends the use offour replicates. The current test method kit con­tains four replicate vials to be used for eachchemical assay.
1.3

Positive, negative, and irritation
control chemicals

Corrositex® provides for both positive and nega­tive controls. The role of these controls is toassure that the test system is working properly
during each trial. To achieve this goal, the con­trols should be able to detect over and under
prediction (relative to the controls) and shouldbe the basis for accepting a test. Thus, thecontrol(s) must be included with each trial. The
negative control serves as a color control for
the CDS so that the operator has immediate ref­erence to the “normal” appearance of the CDS
under the test conditions. This is very helpfulwhen a subtle change in color upon break­through of the test chemical or chemical mix­
ture is expected. The positive control evaluates
the proper function of the assay system(biobarrier, CDS, etc.) and the operator.

A letter dated November 3, 1998 from Dr.
Rosalind Wei of IVI indicated that the control
values must be within a specified range for thedata to be accepted. However, no provision ismade for the performance of the controls to berecorded on the IVI Corrositex® Data Sheet(7/98 Rev.3). Such information should be in­cluded.
Corrositex® does not make provision for deter­mining the irritancy of noncorrosives nor doesit make any such claim.
1.4

Strengths and/or limitations

Corrositex® is a non-animal means of estimat­
ing the dermal corrosivity potential of a test
chemical or chemical mixture. The test is rapid,
relatively simple, and appears to be less expen­
sive than the comparable in vivo rabbit test. A
clear and detailed protocol is available; concur­
rent positive and negative controls are included
to determine the fitness of each trial. The dataon coded compounds tested over time and inseveral laboratories indicates excellent perfor­
mance with regard to inter- and intra-laboratory
reproducibility. However, one member of the
PRP felt that additional interlaboratory valida­

The standard Corrositex® kit provides sufficient
test system components to test both positive andnegative controls as well as four replicates ofthe sample. Positive and negative control
chemicals do not necessarily need to be thosesuggested by IVI. Very strong acids are unlikely
to show appreciable underprediction, especially
if a relatively broad range of breakthrough times
compared to the full range of the Packing GroupI limits is used. In the validation studies
27

Corrositex® Evaluation

Test Method Description

tion studies using laboratories with no previous
experience in conducting the assay were needed
before an accurate assessment of reproducibil­
ity can be made.

cision are animal-to-animal differences in re­sponse within an assay and inter- and intra-labo­
ratory reproducibility. Such measures of in vivo
precision were not available in the Submission.
However, a limited measure of animal-to-ani­
mal variability is available for the ECVAM Vali­
dation Study (Fentem et al., 1998) (Table 3).
This in vivo reference data, compiled by theEuropean Centre for Ecotoxicology and Toxi­
cology of Chemicals (ECETOC, 1995), showsthat variation exists in the numbers of animals
tested and in the response observed.

One advantage of this assay compared to the invivo rabbit skin corrosivity assay is the poten­
tial for developing a comprehensive databaseon coded compounds tested over time in sev­
eral laboratories to provide a clear measure ofinter- and intra-laboratory variations in assay
responses. Since controls are not incorporated
into the in vivo assay, the only measures of pre­Table 3. In Vivo Reference Data for 17 Corrosive Chemicals Evaluated in the ECVAM
Validation Study (ECETOC, 1995)
ECVAM (#) and Name

ECVAMChem
Class

PII

ExposureN

Response(15) dimethyldipropylenetri­amine(13) 3-methoxypropylamine(17) dimethylisopropylamine(45) heptylamine(48) glycol bromoacetate (85%)(23) 2-tert-butylphenol(18) KOH (10%)(42) 2-mercaptoethanol (Na)Org. Base

NPC

4 hr

1

Ne @ 1 hr

Org. Base
Org. Base
Org. BaseElectrophile
PhenolInorg. Base
Inorg. Base

6.7
5.6
6.7
7.7
5.7
NPC
NPC

4 hr
4 hr
4 hr
4 hr
4 hr
4 hr
3 min

6
6
6
1
6
3
3

Org. Acid

NPC

4 hr

3

Org. Acid

NPC

4 hr

3

Org. Acid
Org. Acid

4.4
5.1

4 hr
4 hr

3
3

Br 6/6 @ 1 hr
Br 6/6 @ 1 hr
Br 6/6 @ 1 hr
Ne 1/1 @ 1 hr
Ne 5/6 @ 1 hr
Ne 3/3 @ D 1
Ne 1/3 @ D 1
2/3 neg @ D 7
Ne 2/3 @ D 1
Ne 3/3 @ D 7
Es 2/3 @ D 1
Es 3/3 @ D 2
Ne 3/3 @ D 2
Ne 3/3 @ D 2

Phenol

>4.0

4 hr

4

Electrophile
Org. Base
Org. Acid
Electrophile

7.2
NPC
>4.0
4.1

4 hr
4 hr
4 hr
4 hr

2
3
4
3

(47) 60/40 octanoic/decanoicacid(29) 65/35 octanoic/decanoicacid(40) octanoic acid(50) 55/45 octanoic/decanoicacid(3) carvacrol(14) allyl bromide(38) tallow amine(36) 2-methylbutyric acid(5) methacrolein

Es 3/4 @ D 1
Es 4/4 @ D 2
Ne 2/2 @ D 7
Ne 2/3 @ D 7
Es 2/4 @ D 7
Ne 3/3 @ D 9

Abbreviations: Br = Burned, Es = Eschar, Inorg. = Inorganic, N = Number of rabbits tested,
Ne = Necrotic, neg = negative (for corrosion), NPC = Not possible to calculate, Org. =Organic, PII = Primary Irritation Index

28

Corrositex® Evaluation

Test Method Description

by chance. The intralaboratory variability wasless than the interlaboratory variability, and only
2/22 laboratories lacked significant correlation
with the intralaboratory ranking of samples. Of
particular interest with respect to Corrositex®
was the frequency and consistency with whichskin necrosis was reported in these in vivo stud­ies. There was considerable scatter in the num­
ber of animals with necrosis (i.e., visible de­struction or irreversible alteration of the tissue[49 CFR 173 App. A, 1992]) for some of theagents tested (Table 4). For example, chemical
E induced necrosis in four out of eight rabbits
in one laboratory, one of eight in a second labo­
ratory, and zero out of eight in the remaining 20
laboratories. This study was conducted in 1968­
1970 using a defined protocol, but prior to theintroduction of the FDA/EPA GLP guidelines.
More recent interlaboratory performance evalu­
ation studies addressing the in vivo dermal irri­
tation assay have not been conducted. The PRP
suggests that it may be useful to compile interand intra-laboratory in vivo corrosivity data forreference chemicals.

A request was made to the appropriate Federal
regulatory agencies for data on the inter- andintra-laboratory reproducibility of the in vivo
corrosivity assay; the National Toxicology Pro­
gram (NTP) Interagency Center for the Evalu­
ation of Alternative Toxicological Methods(NICEATM) was informed by agency represen­tatives that these data were either not available
or not readily available. However, Weil and
Scala (1971) examined intra- and inter-labora­
tory variability in the results of eye and skinirritation tests. Standard protocols were usedby 22 laboratories to test 12 reference chemi­cals. For the skin test, eight rabbits were used
for each agent and 0.5 mL was applied for 24hours under semiocclusive bindings. A portionof the evaluation dealt with how laboratories
ranked samples, a measure of interlaboratory
variability. Stated differently, did laboratories
rate agents of low irritancy differently fromthose of high irritancy?
The laboratories, as a whole, ranked the agents
much more consistently than would be expected

Table 4. Necrosis Observed in the Weil and Scala (1971) Study
Agent

E
F
G
I
J
J-1**
K
L
M
M-1**
N
O

Number of Laboratories Reporting Necrosis in Eight Rabbits
0/8

1/8

20
12
19
18
14
13
15
8
14
13
21
21

1
1
2
2
2
2
2

2/8

3/8

4/8

5/8

6/8

7/8

8/8

1
1

1

2

1*

5

1
1
1*
1

3
3

1
1
3***

3
8

2*
2*
2*
2*
2
1
1
1
1

1
1
1

4
4

1

1

*1/8 rabbits died in one laboratory.
**Laboratory 31 reported two sets of data for this sample. 0/8 with necrosis in one run and 7/8 in theother.
***1/8 rabbits died in two laboratories.

29

Corrositex® Evaluation

Test Method Description

tested using Corrositex® precluded an analysisof the predictive value of this assay for untested
complex mixtures.

Based on the available data, there is uncertainty
as to the precision of the reference data against
which Corrositex® is compared. With this limi­
tation of the reference data in mind, the only
limitation of Corrositex® that can be stated quan­titatively is the fraction of the test chemicals
and chemical mixtures within each test set that
did not qualify for testing. Estimates of speci­
ficity and sensitivity of the Corrositex® data
against the in vivo data might be viewed as“worst case” since they presume 100% preci­sion for the in vivo test.

1.5

Editorial/technical corrections

No specific editorial/technical corrections wereidentified other than those already indicatedabove.
1.6

Recommendations

The following specific changes to the protocol
were recommended:

Corrositex® is correlative in nature and is notbased on mechanistic principles. A major limi­
tation of the method is the large proportion ofchemicals and chemical mixtures that do not
qualify for testing by Corrositex®. Based on an
analysis by NICEATM (Appendix G), the ma­
jority (49) of nonqualifying chemicals andchemical mixtures for which pH data were alsoavailable (N=50) had a pH between three andten. Of the 75 nonqualifying chemicals andchemical mixtures for which in vivo data wereavailable, 85% were classified as noncorrosivein the in vivo test, suggesting that there is only
a 15% likelihood that a nonqualifying chemi­
cal or chemical mixture will be corrosive. Otherin vitro methods for corrosivity (e.g., rat skin
TER assay and EPISKINTM) have not shown thissame limitation (Fentem et al., 1998).
Another limitation of Corrositex® is the rela­
tively high number of false positive and false
negatives in some chemical classes (see Sec­tion 3.6). Also, the lack of composition infor­
mation for the undefined complex mixtures

30

(1)

It should be explicitly stated that thebiobarrier should be allowed to harden
on a level surface and to cool overnight
before use.

(2)

Even though replicate variability has
been shown to be very low, guidanceshould be provided on how to evaluate
an aberrant value.

(3)

The IVI Corrositex® Data Sheets pro­vided with the test kit should have a pro­vision for recording the performance ofthe positive and negative controls.
These controls should be used to deter­mine the suitability of the test results.

(4)

Description of the test protocol would
benefit from the addition of a flow dia­gram illustrating the steps in the proce­dure.

2.0 TEST METHOD DATA QUALITY
2.1

sheets that were provided in confidence to
ECVAM by an industrial company. The crite­
ria used in the selection of test chemicals aredetailed in Barratt et al. (1998) and the criteria
adopted during the ECETOC review are pro­vided in the report by the Working Party (Bagley
et al., 1996). All in vivo studies are stated tohave been carried out in accordance with theOrganisation for Economic Co-Operation andDevelopment (OECD) Guideline for Testing ofChemicals: Acute Dermal Irritation/Corrosion(OECD, 1992).

Quality control and quality assurance
procedures including data audits

The in vitro and in vivo experiments conductedby IVI were not in accordance with GLP guide­lines. However, audits were conducted by
NICEATM and by the NTP Quality Assurance
Unit (QAU) that compared the data provided in
the Submission against original study records
to verify accuracy and completeness (Appen­
dix N). Although the audits identified missing
GLP-required information (e.g., data, labora­
tory/facility records, Standard Operating Pro­
cedures (SOPs), protocols, written amendments
and deviations), the auditors concluded that theerrors and omissions found did not alter the cred­ibility of the IVI database and that the data could
be evaluated with confidence. The PRP agreed
with this conclusion.

2.2

Protocol consistency during valida­tion

IVI used the January 1995 version of theCorrositex® protocol in generating all IVI sub­mitted data. Audits of the study-specific infor­
mation provided to support the Submission in­
dicate that there were no chemical-specific pro­
tocol amendments or deviations. The data re­sulting from the Prevalidation and ECVAM
Validation Studies (Botham et al., 1995, Fentem
et al., 1998) followed an established protocol.
As discussed in Section 1.1.2, the IVI and vali­
dation study protocols differed in regard to thelength of the refrigeration cooling period be­fore the biobarriers were to be used; in the se­lection of positive and negative controls; and in
the use of a categorization step. These differ­ences do not invalidate the studies conductedby either organization. It is suggested that IVI
include the reporting of positive/negative con­trol values in the protocol in order for an objec­
tive assessment to be made as to whether thecontrols meet the specified acceptance criteria
and whether the test is working properly.

Corrositex ® tests in the Prevalidation and
ECVAM Validation Studies (Botham et al.,
1995; Fentem et al., 1998) were stated to havebeen conducted in the “spirit” of GLP. Thus,
one of the two laboratories involved in thePrevalidation Study and the three laboratories
involved in the ECVAM Validation Study had
experience in conducting GLP studies for sub­mission to regulatory authorities. A formal au­
dit of the ECVAM data by a QAU was not con­ducted; however, all data submitted by the par­ticipating laboratories were verified against theoriginal data sheets by ECVAM staff on at least
three separate occasions. Similarly, rigorouschecks of all calculations, data analyses, etc.,
were conducted independently by ECVAM staff
and the Management Team representatives ofthe lead laboratories. In vivo data for 49 of the
60 chemicals tested in the validation studies
were obtained from ECETOC (1995). Data forthe remaining 11 chemicals were from data

In the Submission, IVI provided an abbreviatedprotocol for the animal studies conducted by a31

Corrositex® Evaluation

Test Method Data Quality

contract laboratory for the validation assess­ment; there was no assurance that this protocol
was rigorously followed throughout the stud­ies. This was a weakness of the Submission,
along with the associated failure to identify
where each chemical or chemical mixture wastested and the date of testing. With respect to
ECVAM, the in vivo studies generally used three
to four animals treated at several sites to pro­vide time course data.

2.3

Recommendations

In future studies, compliance with GLP guide­lines and inclusion of quality control procedures,
would improve data quality and credibility.
Positive and negative control values should bereported concurrently with each assay to deter­mine if the test is working properly.

323.0 TEST METHOD PERFORMANCE
3.1

Data presentation

not represent the entire chemical population ofinterest for corrosivity testing. The Submission
did not provide sufficient detail to permit a com­prehensive evaluation of the total data of 118
chemicals and chemical mixtures. The areasthat confounded evaluation were:

The Submission provided in vitro and in vivo
data on 118 chemicals and chemical mixtures;
all data were supported by paper documenta­
tion. Fifty-five of the chemicals and chemical
mixtures consisted of mixtures and proprietaryproducts whose compositions were not pro­vided. The remaining 63 defined chemicals andchemical mixtures in the Submission and thedata in the Prevalidation Study (Botham et al.,1995) and ECVAM Validation Study (Fentem
et al., 1998) were grouped into four chemicalclasses. Five of the 63 IVI defined chemicals
and chemical mixtures were unclassified. The
four chemical classes were (1) inorganic andorganic acids and acid mixtures, (2) acid de­rivatives; (3) amines (organic bases), and (4)inorganic bases and base mixtures. The 55
chemicals and chemical mixtures with unknown
composition in the IVI database and similar
chemicals and chemical mixtures in the valida­tion studies were grouped into three productclasses: (1) cleaners and detergents; (2) unde­
fined industrial chemicals; and (3) surfactants,
with one chemical or chemical mixture remain­
ing unclassified. The chemicals evaluated in
the validation studies were classified as inor­
ganic acids, organic acids, inorganic bases, or­
ganic bases, neutral organics, phenols,
electrophiles, inorganic salts, and surfactants.
For the PRP evaluations, all chemicals andchemical mixtures were classified according to
the chemical class scheme used by IVI. The
chemical classes provided in the US DOT Ex­
emption were similar to the chemical classifi­
cation scheme used in the Submission.

• The lack of composition information for 55
chemicals and chemical mixtures. Such in­formation is proprietary and was not pro­vided to IVI by the manufacturer. Although
positive results by qualified chemicals andchemical mixtures would yield usefulcorrosivity results for a particular complex
mixture, the lack of composition informa­tion precluded an analysis of the predictive
value of Corrositex® for untested complex
mixtures.

• With the exception of the ECVAM Valida­tion Study (Barratt et al., 1998), primary ir­
ritation scores for each substance were notprovided. This information would havebeen helpful for understanding the irritancy
potential of the chemicals and chemical
mixtures evaluated. The lack of this infor­
mation ultimately affected the PRP’s abil­
ity to comment on the ability of the assay to
distinguish between highly irritating versus
corrosive chemicals and chemical mixtures.

• Some chemical classes were too broadly
defined to make specific conclusions about
the utility of Corrositex® for that class. For
example, a possible subclassification alter­
native for acid derivatives would have been
to classify these chemicals based on struc­ture, pH, and reserve acidity. More specificclass designations such as anhydrides,
haloacids, salts, etc., would have been help­
ful.

The criterion used by IVI and ECVAM to se­lect the chemicals and chemical mixtures forevaluation was reasonable, where stated, but
potentially biased. That is, the database may• For some chemical classes, the number of33

Corrositex® Evaluation

Test Method Performance

3.2

chemicals in the database was too few or
the distribution of corrosives versus
noncorrosives too unbalanced to ensure anadequate evaluation of performance.

Adequacy of prediction of endpointof interest

The demonstrated linkage between Corrositex®
and the in vivo rabbit skin corrosivity test is theability of the assay to correctly identify in vivo
rabbit corrosive and noncorrosive compounds.
The generally favorable accuracy analysis of thein vitro data with the in vivo test results sup­ports such a linkage. Presumably, this linkage
is also predicated on the biological relevanceof the in vitro model; the diffusion through and/or the destruction of a collagen-based barrier issuggested to be analogous to chemical-induced
corrosion of rabbit skin. The assay is highly
pH and reserve acidity and alkalinity sensitive(i.e., the more acidic or basic the chemical orchemical mixture, the more likely it is to givean accurate prediction). This is consistent withwhat is known about the in vivo dermal corro­sion potential of a chemical or chemical mix­
ture. However, based on the databases evalu­
ated, the assay had false positive (30-100%;
Tables 5 and 9, respectively) and false negative(15-21%; Tables 5 and 6, respectively) rates thatwere considered to be excessive for somechemical and product classes. For the databaseevaluated (Submission plus both validation
studies), the false positive rate was consideredby the PRP to be excessive for all chemical andproduct classes except surfactants (Tables 5-14).
The false negative rates were also consideredby the PRP to be excessive in the overall dataset (Table 5), and for amines (Table 8) and in­organic and organic acids and acid mixtures(Table 6). As indicated by the generally highfalse positive rates, Corrositex ® tends tooverpredict corrosivity potential as compared
to in vivo data. Among the 163 chemicals andchemical mixtures that qualified, the accuracyof Corrositex® with the in vivo test was 79%.

At the request of ICCVAM, nonqualifying
chemicals and chemical mixtures were not in­cluded by IVI in the 1998 Submission. How­ever, the proportion of nonqualifying chemicals
and chemical mixtures can be estimated fromthe validation studies, the 1996 IVI Submission,and other relevant databases:• In the Prevalidation Study (Botham et al.,1995), testing was conducted in two labo­
ratories; the proportion of nonqualifying
chemicals in the two laboratories were 24%(12/50, Laboratory A) and 27% (13/48,
Laboratory B). For noncorrosive chemicals,
32% (8/25) were nonqualifying in both labo­
ratories. For corrosive chemicals, 16%(4/25) and 22% (5/23) were nonqualifying
in Laboratories A and B, respectively.

• In the ECVAM Validation Study (Fentem
et al., 1998), the proportion of nonqualifying
chemicals was 37% (22/60). For noncorro­
sive chemicals, 58% were nonqualifying,but only 10% of the corrosive test samples
were nonqualifying.

• The proportions of nonqualifying chemicals
and chemical mixtures observed in three in­dustrial studies by Gordon et al. (1994) were8.1% (3/37), 31.7% (13/41), and 0% (0/47)
for chemicals/agrochemicals, petrochemi­
cals, and cleansers/surfactants, respectively.

• In the 1996 IVI Submission to ICCVAM,
the proportion of nonqualifying chemicals
and chemical mixtures was 16.5% (83/502).
The overall rate of nonqualifying chemicals andchemical mixtures for all databases combined
was 18% (133/733).

34

Corrositex® Evaluation

3.3

Test Method Performance

Adequacy of test method perfor­
mance evaluation

population decreases, the predictive value de­creases strikingly, even with high values for
specificity and sensitivity (Purchase, 1982).

In support of the PRP, the performance ofCorrositex® was evaluated by NICEATM using
the data submitted by IVI and from the two vali­
dation studies (Botham et al., 1995; Fentem etal., 1998). Accuracy, sensitivity, specificity,
positive predictivity11, negative predictivity12,
false positive rate13, and false negative rate14
were determined for the total database and foreach of the three data sets. Corrositex® data
published by Gordon et al. (1994) were excluded
from the performance analysis since the refer­ence data were obtained from a US DOT Table(49 CFR 172.101, 1992) and actual in vivo re­sults were not available. The sensitivity varied
from 71 to 92% for the three studies (Table 6).
The remaining performance calculations among
the three data sets appear to be comparable.

3.4

Adequacy of test method perfor­
mance data

It would have been helpful if the Submission
had included a comprehensive evaluation of thevariability in breakthrough times among repli­
cate tests for the 118 chemicals and chemical
mixtures tested. Inter- and intra-laboratory re­producibility of Corrositex® was evaluated for­mally within the ECVAM Validation Study(Fentem et al., 1998) using analysis of variance(ANOVA) methods. The results of these analy­
ses indicate that the within and between labora­
tory reproducibility for Corrositex® was excel­
lent and that the variability in assay results was
acceptable.
3.5

The Submission and the validation studies pre­sented not only the results of tests conductedwith individual chemicals and chemical mix­tures but also included several of the usual sta­tistical parameters to evaluate the validity of a
new method. Absent from the evaluations wasa discussion of how predictive value varies withprevalence. As the prevalence of corrosive
chemicals and chemical mixtures in the test

The adequacy of the chemicals/prod­
ucts (numbers/types) selected to evalu­
ate the performance of the method foreach chemical/product class

IVI provided data on 118 chemicals and chemi­
cal mixtures. However, the number of chemi­
cal classes represented by these 118 chemicals
and chemical mixtures is limited, and generali­zations on performance should not be madebeyond these chemicals and chemical classes.
Furthermore, of the 118 separate chemicals andchemical mixtures whose data were provided
by IVI, 63 were defined chemicals and 55 werechemicals and chemical mixtures of unknown
composition. While analysis of the 55 chemi­cals and chemical mixtures of unknown com­position can provide supporting information on
performance, the formal performance analysis
focused on the defined test samples. The Sub­mission included samples from seven chemi­
cal/product classes: inorganic and organic ac­
ids and acid mixtures (n=22), acid derivatives(n=14), amines (n=14), inorganic bases and base11

Positive predictivity is defined as the proportion of cor­
rect positive responses among materials testing positive(NIEHS, 1997). The positive predictivity is a functionof the sensitivity of the test and the prevalence of posi­
tives among the chemicals tested.
12
Negative predictivity is defined as the proportion ofcorrect negative responses among materials testing nega­tive (NIEHS, 1997). The negative predictivity is a func­tion of the sensitivity of the test and the prevalence ofnegatives among the chemicals tested.
13
False positive rate is defined as the proportion of all
negative (noncorrosive) substances that are falsely iden­tified as positive (NIEHS, 1997).
14
False negative rate is defined as the proportion of all
positive (corrosive) substances that are falsely identified
as negative (NIEHS, 1997)35

Corrositex® Evaluation

Test Method Performance(Fentem et al., 1998; Botham et al., 1995). The
Gordon et al. (1994) data set was not included
since the Corrositex® responses were comparedagainst the US DOT-assigned packing group
designations specified in the Hazardous Mate­rials Table (49 CFR 172.101, 1992) instead ofavailable in vivo data. However, considerationof this data set provides value from a weight­of-evidence perspective, and is therefore in­cluded in the performance analysis tables(Tables 5-14). Performance characteristics ofthe total data set, including the Gordon et al.
(1994), are also provided in the tables for thesame reason. Unless otherwise specified, thevalues provided in the following subsections
represent the data set including the Submission
and the two validation studies only.

mixtures (n=8), cleaners and detergents (n=18),
industrial chemicals (n=22), and surfactants(n=14). This chemical classification scheme issimilar to that provided in the US DOT Exemp­tion. The Prevalidation Study (Botham et al.,1995) classified chemicals as inorganics (n=6),
organic acids (n=13), organic bases (n=11), neu­
tral organics (n=10), amine oxides (n=2), an­ionic surfactants (n=3), and cationic surfactants(n=5). The ECVAM Validation Study (Barratt
et al., 1998; Fentem et al., 1998) classified
chemicals as inorganic acids (n=7), organic ac­
ids (n=11), inorganic bases (n=4), organic bases(n=10), neutral organics (n=9), phenols (n=5),
electrophiles (n=8), inorganic salts (n=3), andsurfactants (n=3). After reclassifying the chemi­cals to meet the IVI chemical and chemical
mixture classification scheme, the number ofchemicals and chemical mixtures per class were:
inorganic and organic acids and acid mixtures(n=36), acid derivatives (n=14), amines (n=25),
inorganic bases and base mixtures (n=10), clean­ers and detergents (n=24), industrial chemicals(n=28), and surfactants (n=22). In addition,organic and inorganic acids and bases were com­bined into one class for evaluation (n=85).

3.6.1

Based on 163 chemicals and chemical mixtures,
Corrositex® has an accuracy of 79% (128/163),a sensitivity of 85% (76/89), a specificity of 70%(52/74), a positive predictivity of 78% (76/98),
a negative predictivity of 80% (52/65), a false
positive rate of 30% (22/74), and a false nega­tive rate of 15% (13/89).

Because of the relatively small numbersof chemicals evaluated in some chemicalclasses and the unbalanced nature of corrosive
versus noncorrosive chemicals (corrosive>>noncorrosive), definitive conclusions as tothe adequacy of Corrositex® for some chemicalclasses were difficult to make with confidence.
3.6

Total chemical and chemical mixtures(Table 5)

3.6.2

Inorganic and organic acids and acidmixtures (Table 6)

Based on the 36 chemicals and chemical mix­tures in this data set, Corrositex® has an accu­racy of 75% (27/36), a sensitivity of 79% (22/28), a specificity of 63% (5/8), a positive
predictivity of 88% (22/25), a negative
predictivity of 45% (5/11), a false positive rateof 38% (3/8), and a false negative rate of 21%(6/28).

Accuracy, sensitivity, specificity, posi­tive predictivity, negative predictivity,
false positive rate, and false negative
rate and chemical classes

For the purposes of this evaluation, the formal
performance evaluation was limited to thechemicals and chemical mixtures evaluated in
the Submission and the two validation studies

36

75
221

Gordon et al. (1994)

Entire Data Set27

%

84

97

79

75

76

82

(185/ 221)(73/ 75)(128/163)(30/40)(28/37)(97/118)

Number

Accuracy16

89

97

85

71

81

92

%

(118/132)(58/60)(76/ 89)(17/24)(17/21)(59/ 64)

NumberSensitivity17

75

100

70

81

69

70

%

( 67/89)( 15/15)( 52/74)( 13/16)( 11/16)( 38/54)

NumberSpecificity18

84

100

78

85

81

79

%

(118/140)(58/58)(76/98)(17/20)(17/21)(59/75)

NumberPositive
Predictivity19

83

88

80

65

73

88

%

( 67/81)( 15/17)( 52/65)( 13/20)( 11/15)( 38/43)

Number

Negative
Predictivity20

25

0

30

19

31

30

%

(22/89)(0/15)(22/74)(3/16)(5/16)(16/54)

NumberFalse Positive Rate21

11

3

15

29

19

8

%

(14/ 132)(2/ 60)( 13/89)(7/24)(4/21)(5/64)

NumberFalse Negative
Rate 22

37
13
36

21
47

ECVAM Validation Study25

Submission Plus Validation
Studies26

Gordon et al. (1994)

Entire Data Set27

%

81

100

75

62

75

82

(38/47)(21/21)(27/36)(8/13)(9/12)(18/22)

Number

Accuracy16

84

100

79

50

80

88

%

(32/38)(20/ 20)(22/ 28)(4/8)(8/10)(15/17)

NumberSensitivity17

67

100

63

80

50

60

%

( 6/9)( 1/1)( 5/8)( 4/5)( 1/2)( 3/5)

NumberSpecificity18

91

100

88

80

89

88

%

(32/35)(20/20)(22/25)

(4/5)

(8/9)

(15/17)

NumberPositive
Predictivity19

50

100

45

50

50

60

%

(6/12)( 1/1)(5/ 11)( 4/8)( 1/2)( 3/5)

Number

Negative
Predictivity20

33

0

38

20

50

40

%

(3/9)

(0/1)

(3/8)

(1/5)

(1/2)

(2/5)

NumberFalse Positive Rate21

16

0

21

50

20

12

%

(6/38)(0/ 20)(6/28)( 4/8)(2/10)(2/17)

NumberFalse Negative
Rate 22

16

This table was created by NICEATM for use by the PRP during their review. It is based on the list of chemicals in Appendix A of this report
Accuracy (concordance) is defined as the proportion of correct outcomes of a method (NIEHS, 1997)
17
Sensitivity is defined as the proportion of all positive chemicals that are correctly classified as positive in a test (NIEHS, 1997)
18
Specificity is defined as the proportion of all negative chemicals that are correctly classified as negative in a test (NIEHS, 1997)
19
Positive predictivity is defined as the proportion of correct positive responses among chemicals or chemical mixtures testing positive. The positive predictivity is a function of the sensitivity of the test andthe prevalence of positives among the chemicals tested (NIEHS, 1997)
20
Negative predictivity is defined as the proportion of correct negative responses among chemicals or chemical mixtures testing negative. The negative predictivity is a function of the sensitivity of the test
and the prevalence of negatives among the chemicals tested (NIEHS, 1997)21
False positive rate is defined as the proportion of all negative (noncorrosive) chemicals or chemical mixtures that are falsely identified as positive (NIEHS, 1997)
22
False negative rate is defined as the proportion of all positive (corrosive) chemicals or chemical mixtures that are falsely identified as negative (NIEHS, 1997)
23
Submission to ICCVAM by InVitro International, Inc. (IVI)
24
Botham et al. (1995)
25
Fentem et al. (1998)
26
This includes chemicals or chemical mixtures provided in the Submission, Prevalidation Study (Botham et al., 1995), and ECVAM Validation Study (Fentem et al., 1998)
27
This includes chemicals or chemical mixtures provided in the Submission, Prevalidation Study (Botham et al., 1995), ECVAM Validation Study (Fentem et al., 1998), and Gordon et al. (1994).

15

12

22

Number ofChemicals

Prevalidation Study24

Submission23

Data Source

Table 6. Evaluation of the Performance of Corrositex® in Predicting Corrosivity/Noncorrosivity Compared to In Vivo Findings (Inorganic and Organic Acids and Acid Mixtures)15

Table 6. Evaluation of the Performance of Corrositex® in Predicting Corrosivity/Noncorrosivity Compared to In Vivo Findings (Inorganic and Organic Acids and Acid Mixtures)15

163

Submission Plus Validation
Studies26

37
40

24

118

Number ofChemicals

ECVAM Validation Study25

Prevalidation Study

Submission23

Data Source

Table 5. Evaluation of the Performance of Corrositex® in Predicting Corrosivity/Noncorrosivity Compare d to In Vivo Findings (Overall)15

Test Method Performance
Corrositex® Evaluation

Corrositex® Evaluation

3.6.3

Test Method Performance

Acid derivatives (Table 7)a specificity of 0% (0/1), a positive predictivityof 90% (9/10), a false positive rate of 100%(1/1), and a false negative rate of 0% (0/9). The
analysis was confounded by the limited num­
ber of chemicals and chemical mixtures tested.
Additionally, more corrosive chemicals andchemical mixtures than noncorrosive chemicals
and chemical mixtures have been tested, result­ing in very low specificity (0%) and a high false
positive rate (100%).

“Acid derivative” is a non-specific class desig­
nation and is broadly defined as an acid pro­
duced from a chemical substance either directly
or by modification or partial substitution. This
class includes anhydrides, haloacids, salts, andother types of chemicals. A more precise clas­
sification of these materials is needed to makea definitive statement about the utility ofCorrositex® for these chemicals.

3.6.6
Based on the chemicals assigned to the acidderivatives class (N=14), Corrositex® has an
accuracy of 93% (13/14), a sensitivity of 100%(7/7), a specificity of 86% (6/7), a positive
predictivity of 88% (7/8), a negative predictivityof 100% (6/6), a false positive rate of 14% (1/7), and a false negative rate of 0% (0/7). Noacid derivatives were included in thePrevalidation Study (Botham et al., 1995), so
these values reflect the chemicals provided in
the Submission and the ECVAM Validation
Study (Fentem et al., 1998).

Pooling the chemical classes containing inor­
ganic and organic bases and base mixtures re­
sulted in a data set of 35 chemicals. For thisclass, Corrositex® has an accuracy of 83% (29/35), a sensitivity of 89% (25/28), a specificity
of 57% (4/7), a positive predictivity of 89% (25/28), a negative predictivity of 57% (4/7), a false
positive rate of 43% (3/7), and a false negative
rate of 11% (3/28).
3.6.7

3.6.4

Amines (organic bases) (Table 8)This data set includes primary, secondary, andtertiary amines. These chemicals are also clas­sified as organic bases when test results are com­bined across chemical classes. Based on the 25
chemicals and chemical mixtures in this dataset, Corrositex® has an accuracy of 80% (20/25), a sensitivity of 84% (16/19), a specificity
of 67% (4/6), a positive predictivity of 89% (16/18), a negative predictivity of 57% (4/7), a false
positive rate of 33% (2/6), and a false negative
rate of 16% (3/19).
3.6.5

Inorganic and organic bases and basemixtures (Table 10)

Organic and inorganic acids and bases(Table 11)

Pooling the chemical classes containing organicand inorganic acids and bases resulted in a rela­
tively large data set of 85 chemicals, with the
distribution of chemicals weighted toward cor­rosives (63 corrosives versus 22 noncorrosives).
For this class, Corrositex® has an accuracy of
81% (69/85), a sensitivity of 86% (54/63), a
specificity of 68% (15/22), a positive
predictivity of 89% (54/61), a negative
predictivity of 63% (15/24), a false positive rateof 32% (7/22), and a false negative rate of 14%(9/63).

Inorganic bases and base mixtures(Table 9)

3.6.8
Based on the ten chemicals and chemical mix­tures in this data set, Corrositex® has an accu­racy of 90% (9/10), a sensitivity of 100% (9/9),

Cleaners and Detergents (Table 12)

Based on the 24 chemicals and chemical mix­tures in this data set, Corrositex® has an accu­
38

%

95

96

93

100

93

(37/39)(26/27)(13/14)(7/7)(13/ 14)

Number

Accuracy29

97

96

100

100

100

%

(31/ 32)(26/27)(7/7)(5/ 5)(7/ 7)

NumberSensitivity30

86

NA

86

100

86

%

(6/ 7)(6/7)(2/ 2)(6/ 7)

NumberSpecificity31

97

100

88

100

88

%

( 31/32)( 27/27)( 7/8)( 5/5)( 7/8)

NumberPositive
Predictivity32

86

0

100

100

100

%

39

%

87

100

80

88

73

93

(27/31)(8/8)(20/25)(7/8)( 8/11)(13/14)

Number

Accuracy29

88

100

84

86

75

91

%

(23/ 26)(8/8)(16/19)(6/ 7)(6/8)(10/ 11)

NumberSensitivity30

80

NA

67

100

67

100

%

(4/ 5)(4/6)(1/ 1)(2/3)(3/ 3)

NumberSpecificity31

96

100

89

100

86

100

%

( 23/24)( 8/8)( 16/18)( 6/6)( 6/7)( 10/10)

NumberPositive
Predictivity32

57

NA

57

50

50

75

%

(4/ 7)(4/ 7)

(1/2)

(2/4)

(3/ 4)

Number

Negative
Predictivity33

(1/7)

(1/7)

(0/2)

(1/7)

Number

20

NA

33

0

33

0

%

(1/5)

(2/6)

(0/1)

(1/3)

(0/3)

NumberFalse Positive Rate34

14

NA

14

0

14

%

False Positive Rate34(1/ 32)(1/27)(0/7)(0/ 5)(0/7)

Number

12

0

16

14

25

9

%

(3/ 26)(0/ 8)(3/19)(1/ 7)(2/8)(1/ 11)

NumberFalse Nega tive
Rate 35

3

4

0

0

0

%

False Nega tive
Rate 35

29

This table was created by NICEATM for use by the PRP during their review. It is based on the list of chemicals in Appendix A of this report
Accuracy (concordance) is defined as the proportion of correct outcomes of a method (NIEHS, 1997)30
Sensitivity is defined as the proportion of all positive chemicals that are correctly classified as positive in a test (NIEHS, 1997)
31
Specificity is defined as the proportion of all negative chemicals that are correctly classified as negative in a test (NIEHS, 1997)
32
Positive predictivity is defined as the proportion of correct positive responses among chemicals or chemical mixtures testing positive. The positive predictivity is a function of the sensitivity of the test andthe prevalence of positives among the chemicals tested (NIEHS, 1997)
33
Negative predictivity is defined as the proportion of correct negative responses among chemicals or chemical mixtures testing negative. The negative predictivity is a function of the sensitivity of the test
and the prevalence of negatives among the chemicals tested (NIEHS, 1997)
34
False positive rate is defined as the proportion of all negative (noncorrosive) chemicals or chemical mixtures that are falsely identified as positive (NIEHS, 1997)
35
False negative rate is defined as the proportion of all positive (corrosive) chemicals or chemical mixtures that are falsely identified as negative (NIEHS, 1997)
36
Submission to ICCVAM by InVitro International, Inc. (IVI)37
Botham et al. (1995)
38
Fentem et al. (1998)
39
This includes chemicals or chemical mixtures provided in the Submission, Prevalidation Study (Botham et al., 1995), and ECVAM Validation Study (Fentem et al., 1998)
40
This includes chemicals or chemical mixtures provided in the Submission, Prevalidation Study (Botham et al., 1995), ECVAM Validation Study (Fentem et al., 1998), and Gordon et al. (1994).

28

NA = Not applicable

Entire Data Set
31

8

Gordon et al. (1994)

40

25

8

Submission Plus Validation
Studies39

ECVAM Validation Study

11

Prevalidation Study37

38

14

Number ofChemicals

Submission36

Data Source(6/ 7)(0/1)(6/ 6)

(2/2)

(6/6)

Number

Negative
Predictivity33

Table 8. Evaluation of the Performance of Corrositex® in Predicting Corrosivity/Noncorrosivity Compared to In Vivo Findings (Amines)28

NA = Not applicable

Entire Data Set
39

27

Gordon et al. (1994)

40

7
14

Submission Plus Validation
Studies390Prevalidation Study37

ECVAM Validation Study38

14

Number ofChemicals

Submission36

Data Source

Table 7. Evaluation of the Performance of Corrositex® in Predicting Corrosivity/Noncorrosivity Compared to In Vivo Findings (Acid Derivatives)28

Corrositex® Evaluation
Test Method Performance

82

100

90

50

100

88

%

(9/11)( 3/3)(9/10)( 2/4)( 1/1)( 7/8)

Number

Accuracy42

100

100

100

100

100

100

%

(9/9)

(3/3)

(9/ 9)

(2/2)

(1/1)

(7/7)

NumberSensitivi ty43

0

NA

0

0

NA

0

%

(0/2)

(0/1)

(0/2)

(0/1)

NumberSpecificity44

82

100

90

50

100

88

%

(9/11)(3/3)(9/10)

(2/4)

(1/1)

(7/8)

NumberPositive
Predicti vity45

NA

NA

NA

NA

NA

NA

%
Number

Negative
Predictivity46

100

NA

100

100

NA

100

%

(2/2)

(1/1)

(2/2)

(1/1)

NumberFalse Positive Rate47

0

0

0

0

0

0

%

(0/9)

(0/3)

(0/9)

(0/2)

(0/1)

(0/7)

NumberFalse Negative
Rate 48

40
12
12
35

11
42

Prevalidation Study50

ECVAM Validation Study51

Submission Plus Validation
Studies52

Gordon et al. (1994)

Entire Data Set53

%

86

100

83

75

75

91

( 36/42)( 11/11)( 29/35)(9/12)(9/12)( 20/22)

Number

Accuracy42

91

100

89

89

78

94

%

(32/ 35)(11/ 11)(25/ 28)

(8/9)

(7/9)

(17/ 18)

NumberSensitivi ty43

57

NA

57

33

67

75

%

(4/7)

(4/7)

(1/3)

(2/3)

(3/4)

NumberSpecificity44

91

100

89

80

88

94

%

(32/35)(11/11)(25/28)(8/10)(7/8)(17/18)

NumberPositive
Predicti vity45

57

NA

57

50

50

75

%

(4/7)

(4/7)

(1/2)

(2/4)

(3/4)

Number

Negative
Predictivity46

43

NA

43

67

33

25

%

(3/7)

(3/7)

(2/3)

(1/3)

(1/4)

NumberFalse Positive Rate47

9

0

11

11

22

6

%

( 3/35)( 0/11)( 3/28)

(1/9)

(2/9)

( 1/18)

NumberFalse Negative
Rate 48

42

This table was created by NICEATM for use by the PRP during their review. It is based on the list of chemicals in Appendix A of this report
Accuracy (concordance) is defined as the proportion of correct outcomes of a method (NIEHS, 1997)
43
Sensitivity is defined as the proportion of all positive chemicals that are correctly classified as positive in a test (NIEHS, 1997)
44
Specificity is defined as the proportion of all negative chemicals that are correctly classified as negative in a test (NIEHS, 1997)
45
Positive predictivity is defined as the proportion of correct positive responses among chemicals or chemical mixtures testing positive. The positive predictivity is a function of the sensitivity of the test andthe prevalence of positives among the chemicals tested (NIEHS, 1997)
46
Negative predictivity is defined as the proportion of correct negative responses among chemicals or chemical mixtures testing negative. The negative predictivity is a function of the sensitivity of the test
and the prevalence of negatives among the chemicals tested (NIEHS, 1997)
47
False positive rate is defined as the proportion of all negative (noncorrosive) chemicals or chemical mixtures that are falsely identified as positive (NIEHS, 1997)48
False negative rate is defined as the proportion of all positive (corrosive) chemicals or chemical mixtures that are falsely identified as negative (NIEHS, 1997)
49
Submission to ICCVAM by InVitro International, Inc. (IVI)50
Botham et al. (1995)
51
Fentem et al. (1998)
52
This includes chemicals or chemical mixtures provided in the Submission, Prevalidation Study (Botham et al., 1995), and ECVAM Validation Study (Fentem et al., 1998)
53
This includes chemicals or chemical mixtures provided in the Submission, Prevalidation Study (Botham et al., 1995), ECVAM Validation Study (Fentem et al., 1998), and Gordon et al. (1994).

41

NA = Not applicable

22

Number ofChemicals

Submission49

Data Source

Table 10 . Evaluation of the Performance of Corrositex® in Predicting Corrosivity/Noncorrosivity Compared to In Vivo Findings (Inorganic and Organic Bases and Base Mixtures)41

Table 10. Evaluation of the Performance of Corrositex® in Predicting Corrosivity/Noncorrosivity Compared to In Vivo Findings (Inorganic and Organic Bases and Base Mixtures)41

NA = Not applicable

Entire Data Set
11

3

53

Gordon et al. (1994)

4
10

Submission Plus Validation
Studies52

ECVAM Validation Study

1

Prevalidation Study50

51

8

Number ofChemicals

Submission49

Data Source

Table 9. Evaluation of the Performance of Corrositex® in Predicting Corrosivity/Noncorrosivity Compared to In Vivo Findings (Inorganic Bases and Base Mixtures)41

Table 9. Evaluation of the Performance of Corrositex® in Predicting Corrosivity/Noncorrosivity Compared to In Vivo Findings (Inorganic Bases and Base Mixtures)41

Test Method Performance
Corrositex® Evaluation

63

58

Gordon et al. (1994)

%

87

98

81

75

75

88

(110/127)(57/58)(69/85)(24/32)(18/24)(51/58)

Number

Accuracy55

90

98

86

77

79

93

%

(94/104)(55/ 56)(54/63)(17/ 22)(15/ 19)(39/ 42)

NumberSensitivity56

70

100

68

70

60

75

%

(16/23)(2/2)(15/22)(7/ 10)(3/ 5)(12/ 16)

NumberSpecificity57

93

100

89

85

88

91

%

(94/101)( 55/55)( 54/61)( 17/20)( 15/17)( 39/43)

NumberPositive
58
Predictivity

62

67

63

58

43

80

%

(16/26)(2/3)(15/ 24)(7/12)(3/ 7)(12/15)

Number

Negative
59
Predictivity

30

0

32

30

40

25

%

41

%

59

100

54

100

40

56

(16/27)(3/3)(13/24)(1/ 1)(2/5)(10/18)

Number

Accuracy55

90

NA

90

NA

100

88

%

(9/10)(9/10)

(2/2)

(7/8)

NumberSensitivity56

41

100

29

100

0

30

%

(7/ 17)(3/3)(4/14)

(1/1)

(0/3)

(3/10)

NumberSpecificity57

47

NA

47

NA

40

50

%

(9/19)(9/19)( 2/5)(7/14)

NumberPositive
Predictivity58

88

100

80

100

NA

75

%

(7/8)

(3/3)

(4/ 5)

(1/1)

(3/4)

Number

Negative
Predictivity59

59

0

71

0

100

70

%

(10/17)(0/3)(10/14)

(0/1)

(3/3)

(7/10)

NumberFalse Positive Rate60(10/ 104)(1/56)(9/63)(5/22)(4/ 19)(3/ 42)

Number

10

NA

10

NA

0

13

%

(1/ 10)(1/10)

(0/2)

(1/8)

NumberFalse Negativ e
Rate61

10

2

14

23

21

7

%

False Nega tive
61
Rate

55

This table was created by NICEATM for use by the PRP during their review. It is based on the list of chemicals in Appendix A of this report
Accuracy (concordance) is defined as the proportion of correct outcomes of a method (NIEHS, 1997)
56
Sensitivity is defined as the proportion of all positive chemicals that are correctly classified as positive in a test (NIEHS, 1997)
57
Specificity is defined as the proportion of all negative chemicals that are correctly classified as negative in a test (NIEHS, 1997)
58
Positive predictivity is defined as the proportion of correct positive responses among chemicals or chemical mixtures testing positive. The positive predictivity is a function of the sensitivity of the test andthe prevalence of positives among the chemicals tested (NIEHS, 1997)
59
Negative predictivity is defined as the proportion of correct negative responses among chemicals or chemical mixtures testing negative. The negative predictivity is a function of the sensitivity of the test
and the prevalence of negatives among the chemicals tested (NIEHS, 1997)
60
False positive rate is defined as the proportion of all negative (noncorrosive) chemicals or chemical mixtures that are falsely identified as positive (NIEHS, 1997)
61
False negative rate is defined as the proportion of all positive (corrosive) chemicals or chemical mixtures that are falsely identified as negative (NIEHS, 1997)
62
Submission to ICCVAM by InVitro International, Inc. (IVI)63
Botham et al. (1995)
64
Fentem et al. (1998)
65
This includes chemicals or chemical mixtures provided in the Submission, Prevalidation Study (Botham et al., 1995), and ECVAM Validation Study (Fentem et al., 1998)
66
This includes chemicals or chemical mixtures provided in the Submission, Prevalidation Study (Botham et al., 1995), ECVAM Validation Study (Fentem et al., 1998), and Gordon et al. (1994).

54

NA = Not applicable3
27

Gordon et al. (1994)

Entire Data Set66

1
24

64

5

18

Number ofChemicals

Submission Plus Validation
Studies65

ECVAM Validation Study

Prevalidation Study63

Submission62

Data Source(7/23)(0/2)(7/22)(3/ 10)(2/5)(4/16)

NumberFalse Positive Rate60

Table 12. Eval uation of the Performance of Corrositex® in Predicting Corrosivity/Noncorrosivity Compared to In Vivo Findings (Cleaners and Detergents) 54

Entire Data Set
127

85

Submission Plus Validation
Studies65

66

32

24

58

Number ofChemicals

ECVAM Validation Study64

Prevalidation Study

Submission62

Data Source

Table 11. Eval uation of the Performance of Corrositex® in Predicting Corrosivity/Noncorrosivity Compared to In Vivo Findings (Organic a nd Inorganic Acids and Bases)54

Corrositex® Evaluation
Test Method PerformanceCorrositex® Evaluation

Test Method Performanceracy of 54% (13/24), a sensitivity of 90% (9/10), a specificity of 29% (4/14), a positive
predictivity of 47% (9/19), a negative
predictivity of 80% (4/5), a false positive rateof 71% (10/14), and a false negative rate of 10%(1/10). No conclusive statement can be madeabout the predictive value of Corrositex® forcleaners and detergents because of the lack of
information about the identity of the ingredi­
ents in each product.
3.6.9

tion on the severity of the corrosive response ofa chemical or chemical mixture so that appro­
priate packing groups may be assigned. US
DOT currently accepts the use of Corrositex®
for assigning such packing groups (Appendix
Q), which are determined by assessing the
breakthrough times of a chemical or chemical
mixture. Information on the ability ofCorrositex® to accurately assign packing groups
was provided in the IVI Submission (Table 23of Appendix C). However, the PRP did not in­vestigate the use of Corrositex® for this purpose.

Undefined industrial chemicals(Table 13)

3.8

Clinical relevance and human
predictivity

Based on the 28 unidentified chemicals andchemical mixtures in this data set, Corrositex®
has an accuracy of 75% (21/28), a sensitivity of
87% (13/15), a specificity of 62% (8/13), a posi­tive predictivity of 72% (13/18), a negative
predictivity of 80% (8/10), a false positive rateof 38% (5/13), and a false negative rate of 13%(2/15). No conclusive statements can be madeabout the predictive value of Corrositex® forundefined industrial chemicals because of thelack of information about the identity of the in­gredients in each product.

The overall accuracy and the positive and nega­tive predictivity indicate that Corrositex® results
are generally similar to those obtained using thein vivo test. Information on which chemicals
and chemical mixtures in the Submission andvalidation studies are human corrosives andnoncorrosives is needed before an assessment
can be made on the performance of this assay
for predicting human response. Such informa­tion is not available.

3.6.10 Surfactants (Table 14)

3.9

Based on the 22 noncorrosive chemicals andchemical mixtures in this data set, Corrositex®
has an accuracy of 100% (22/22), a specificityof 100% (22/22), a negative predictivity of
100% (22/22), and a false positive rate of 0%(0/22). No conclusive statements can be said
about this class of chemicals and chemical mix­tures since the ingredients in the chemicals andchemical mixtures are not known and the only
chemicals and chemical mixtures evaluatedwere noncorrosive.

Corrositex® is limited in its universal utility
because of the proportion of chemicals that are
not compatible with the CDS and thus cannot
be evaluated. Corrositex® performance indi­cates that, in specific testing circumstances suchas that required by US DOT, Corrositex® is use­
ful as a stand-alone assay for evaluating thecorrosivity or noncorrosivity of acids, bases, andacid derivatives. The current US DOT exemp­tion allows the use of Corrositex® for assigning
packing groups for acids, acid derivatives, acyl
halides, alkylamines and polyalkylamines,
bases, chlorosilanes, metal halides, andoxyhalides. However, the database evaluatedby the PRP did not include acyl halides,
chlorosilanes, metal halides, or oxyhalides; thus

3.7

UN Packing Group Classification

To ensure safety in the transport of hazardous
materials, US DOT requires additional informa­
42

Regulatory utility of the method

%

77

100

75

67

100

73

(23/30)(2/2)(21/28)(2/ 3)(3/ 3)(16/22)

Number

Acc uracy68

87

NA

87

0

NA

93

%

(13/15)(13/15)(0/1)(13/14)

NumberSensitivity69

67

100

62

100

100

38

%

(10/ 15)(2/2)(8/ 13)

(2/2)

(3/3)

(3/ 8)

NumberSpecificity70

72

NA

72

NA

NA

72

%

(13/ 18)(13/18)(13/ 18)

NumberP ositive
Predictivity71

83

100

80

67

100

75

%

(10/12)(2/ 2)(8/10)

(2/3)

(3/3)

(3/4)

Number

Negative
Predictivity72

43
22

5

Submission Plus Validation
Studies78

Gordon et al. (1994)

%

100

100

100

100

100

100

(27/ 27)(5/5)(22/22)(2/ 2)(5/ 5)(14/ 14)

Number

Acc uracy68

100

100

NA

NA

NA

NA

%

(1/1)

(1/1)

NumberSensitivity69

100

100

100

100

100

100

%

(26/26)(4/4)(22/ 22)

(2/2)

(5/5)

(14/14)

NumberSpecificity70

100

100

NA

NA

NA

NA

%

(1/1)

(1/1)

NumberP ositive
Predictivity71

100

100

100

100

100

100

%

(26/ 26)(4/4)(22/22)

(2/2)

(5/5)

(14/14)

Number

Negative
Predictivity72(5/ 15)(0/2)(5/ 13)

(0/2)

(0/3)

(5/8)

Number

0

0

0

0

0

0

%

(0/26)(0/ 4)(0/ 22)

(0/2)

(0/5)

(0/ 14)

NumberFalse Positive Rate73

33

0

38

0

0

63

%

False Positive Rate73(2/15)

NA(2/ 15)(1/ 1)(1/ 14)

0

0

NA

NA

NA

NA

%

(0/1)

(0/1)

NumberFalse Negative
Rate61

13

NA

13

100

NA

7

False Negative
Rate61%
Number68

This table was created by NICEATM for use by the PRP during their review. It is based on the list of chemicals in Appendix A of this report
Accuracy (concordance) is defined as the proportion of correct outcomes of a method (NIEHS, 1997)
69
Sensitivity is defined as the proportion of all positive chemicals that are correctly classified as positive in a test (NIEHS, 1997)
70
Specificity is defined as the proportion of all negative chemicals that are correctly classified as negative in a test (NIEHS, 1997)
71
Positive predictivity is defined as the proportion of correct positive responses among chemicals or chemical mixtures testing positive. The positive predictivity is a function of the sensitivity of the test andthe prevalence of positives among the chemicals tested (NIEHS, 1997)
72
Negative predictivity is defined as the proportion of correct negative responses among chemicals or chemical mixtures testing negative. The negative predictivity is a function of the sensitivity of the test
and the prevalence of negatives among the chemicals tested (NIEHS, 1997)
73
False positive rate is defined as the proportion of all negative (noncorrosive) chemicals or chemical mixtures that are falsely identified as positive (NIEHS, 1997)
74
False negative rate is defined as the proportion of all positive (corrosive) chemicals or chemical mixtures that are falsely identified as negative (NIEHS, 1997)
75
Submission to ICCVAM by InVitro International, Inc. (IVI)76
Botham et al. (1995)
77
Fentem et al. (1998)
78
This includes chemicals or chemical mixtures provided in the Submission, Prevalidation Study (Botham et al., 1995), and ECVAM Validation Study (Fentem et al., 1998)
79
This includes chemicals or chemical mixtures provided in the Submission, Prevalidation Study (Botham et al., 1995), ECVAM Validation Study (Fentem et al., 1998), and Gordon et al. (1994).

67

NA = Not applicable

Entire Data Set
27

2

79

5

ECVAM Validation Study77

14

Number ofChemicals

Prevalidation Study76

Submission75

Data Source

Table 14. Eval uation of the Performance of Corrositex® in Predicting Corros ivity/Noncorrosivity Compared to In Vivo Findings (Surfactants)67

NA = Not applicable

Entire Data Set
30

2

Gordon et al. (1994)

79

28

Submission Plus Validation
Studies78

3
3

76

22

Number ofChemicals

ECVAM Validation Study77

Prevalidation Study

Submission75

Data Source

Table 13. Eval uation of the Performance of Corrositex® in Predicting Corrosivity/Noncorrosivity Compared to In Vivo Findings (Industrial Chemi cals)67

Test Method Performance
Corrositex® Evaluation

Corrositex® Evaluation

Test Method Performancecerned about potential false positive responses.
In either testing strategy, an investigator may
conclude that confirmation testing is necessary
based on supplemental information. As addi­
tional test results with Corrositex® are obtained,
the utility of the assay may need to be reconsid­
ered.

no statement can be made by the PRP for thesechemical classes. In other testing circum­
stances, and for other chemical and productclasses, Corrositex® may be more appropriately
used as part of a tiered assessment, in which
negative responses must be followed by dermal
irritation testing, and positive responses require
no further testing unless the investigator is con­44

4.0 TEST METHOD RELIABILITY80(REPEATABILITY81/REPRODUCIBILITY82)
4.1

Adequacy of intralaboratory repeat­ability and reproducibility evalua­
tions

ticularly when the mean is in the range of theexperimental variability of the cut-off value
between packing group designations. For ex­
ample, the breakthrough times for hydrobromic
acid (Packing Group II assigned on the basis of
the in vivo test) are 2.53 and 2.03 minutes, giv­
ing a mean of 2.28 minutes and a SD of 0.35.
Since the mean is less than three minutes, hy­drobromic acid is classified to be in Packing
Group I, an over-prediction compared to the invivo test results. The determination of optimal
cut-off values is critical for Corrositex®, but was
not addressed in the Submission. The cut-off
value of three minutes for separating Packing
Groups I and II is particularly important, since
it represents a relatively short time interval. It
is not clear whether the cut-off values assigned
have taken into consideration the experimental
variability as well as the number of replicates
used.

The Submission addresses the issue of
intralaboratory variability. Data points were
provided for six reference chemicals (n > 200).
The standard deviations (SDs) of the break­through times for two of the six chemicals werereported to be about 5% of the mean values; forthree others they were reported to be approxi­
mately 10%, and for the sixth chemical orchemical mixture the SD was shown to be about
18% (of a very small number). These data were
not part of the data set audited.
In the Submission, individual breakthroughtimes of less than 240 minutes were provided
for 80 chemicals and chemical mixtures. The
number of replicates for these 80 chemicals/
products ranged from two to six. The coeffi­
cients of variation (CVs) for intralaboratory
variability were calculated for these 80 chemi­cals and chemical mixtures. With few excep­
tions, the CVs for these chemicals and chemi­
cal mixtures were all less than 5%. The maxi­
mum CV was 15.6%, which occurred for two
chemicals (hydrobromic acid and 10­
undecenoic acid). However, a mean value basedon two replicates is probably not reliable, par­There has been limited, but probably sufficient,assessment of the intralaboratory reproducibil­
ity of Corrositex®. This conclusion is based on
an assessment of all data, including those fromthe Prevalidation and Validation Studies and the
IVI submissions to US DOT. It also takes into
account the evaluation of the interlaboratory re­producibility of Corrositex® (see Sections 4.2­4.4), assuming that if the test results are repro­
ducible between laboratories, they are also likely
to be reproducible when tested within the samelaboratory.

80

Reliability is defined as a measure of the degree towhich a test can be performed reproducibly within andamong laboratories over time (NIEHS, 1997).
81
Repeatability is defined as the closeness of agreement
between test results obtained within a single laboratorywhen the procedure is performed on the same substanceunder identical conditions within a given time period(NIEHS, 1997).
82
Reproducibility is defined as the variability between
single test results obtained in a single laboratory(intralaboratory reproducibility) or in different laborato­
ries (interlaboratory reproducibility) using the same pro­
tocol and test samples (NIEHS, 1997).

4.2

Adequacy of interlaboratory repro­
ducibility evaluations

For chemicals and chemical mixtures that canbe tested using Corrositex®, two types of data
are produced. One set that includes specificbreakthrough times is continuous; the other set
45

Corrositex® Evaluation

Test Method Reliability

is categorical and includes the breakthroughtimes recorded as >240 minutes for Category 1
test chemicals and chemical mixtures or as >60
minutes for Category 2 test chemicals andchemical mixtures. The latter set consists ofchemicals and chemical mixtures that did not
penetrate the biobarrier within the timescale
defined by the prediction model.

classified as corrosive in one laboratory andnoncorrosive in the others.
One PRP member felt that insufficient data wereavailable from independent laboratories to as­
sess fully interlaboratory reproducibility. How­ever, the unanimous consensus of the other PRP
members was that there has been adequate
evaluation of the interlaboratory reproducibil­
ity of Corrositex®, although conducting addi­
tional studies with less-experienced laborato­
ries and a larger number of test chemicals andchemical mixtures could be informative. The
reported interlaboratory reproducibility reflects
the training and expertise of the laboratories par­ticipating in the validation studies. It is sug­gested that laboratories unfamiliar with conduct­
ing the test should obtain similar training andconduct tests with test reference chemicals be­fore undertaking any testing of unknown chemi­cals and chemical mixtures. The in vitro test
appears to be precise (i.e., the data points werein close agreement).

The Submission addressed the issue of theinterlaboratory reproducibility of Corrositex®.
Ten chemicals were tested in five laboratories
with six replicates per test chemical or chemi­
cal mixture. The extent of interlaboratory agree­
ment appears to be acceptable. An ANOVA
approach for estimating within-laboratory andbetween-laboratory variability would have been
preferred.
Two studies were performed to evaluate spe­cifically interlaboratory reproducibility: (1) adouble-blind study of 29 chemicals which dem­
onstrated an interlaboratory reproducibility of
93%, and (2) an end-user evaluation of 20
chemicals which demonstrated a reproducibil­
ity of 95%.

4.3

In the ECVAM Validation Study (Fentem et al.,1998), the three laboratories differed in only
three cases in obtaining continuous or categori­cal values (i.e., corrosive versus noncorrosive
results). Statistical evaluation of the intra- andinter-laboratory variabilities of the continuous
data (the results for 20 of the 60 chemicals) in­
dicated no systematic bias. The between-labo­
ratory reproducibility of the breakthrough times
was acceptable. Within laboratories, there wereno cases where the corrosivity classification
changed from one run to the next, although there
was one case where a chemical or chemical
mixture was nonqualifying in one run and non­corrosive in the other. Interlaboratory differ­ences in classification were also quite rare; there
were only two cases where a chemical was

Reproducibility of reference chemi ­cals or products

Results specifically for reference chemicals orcontrols were not available for evaluation.
However, data on appropriate test chemicals andchemical mixtures have been reported (see Sec­tion 4.2), which enable an adequate assessmentof the reproducibility of Corrositex® both within
and between laboratories.
4.4

Repeatability and reproducibility of
results

The results appear to be sufficiently repeatable
and reproducible, both within and between labo­
ratories.
The ECVAM Validation Study (Fentem et al.,1998) involved the testing of 60 coded chemi­46

Corrositex® Evaluation

Test Method Reliability

chemicals were reported as non-qualifying by
at least one laboratory). However, there were
only two cases where a chemical was classified
as corrosive by one laboratory and noncorro­
sive by the others.

cals in three laboratories. In this study, somedifferences were found between the three labo­
ratories in relation to the qualification of the test
chemicals and chemical mixtures. For 26 of
the 60 chemicals (43% of the test chemicals andchemical mixtures in the validation study), one
or more laboratories found the chemical to be
non-qualifying. In 18 of these cases, all threelaboratories were unable to qualify the chemi­cal, while in the remaining eight cases at least
one laboratory qualified the chemical or chemi­
cal mixture and obtained a predicted corrosivity
classification. In all of these eight cases, theclassification determined was noncorrosive.
This problem of nonqualification was especiallyobvious for the neutral organics (all nine of theneutral organics were nonqualifying in at least
two of the laboratories), phenols (all five were
nonqualifying in at least two of the laborato­ries), and electrophiles (seven of the eight

4.5

Reproducibility and reliability ofCorrositex® versus standard in vivo
assays

The reproducibility of Corrositex® is expected
to be better than that of most biological tests,
since Corrositex® involves a standardized
physico-chemical test system rather than a bio­
logical endpoint. It is impossible to compare
directly the reproducibility of the in vitro andanimal tests due to the lack of objective infor­
mation on the intra- and inter-laboratory repro­
ducibility of the rabbit skin corrosivity test pro­cedure.

47

48

5.0 OTHER SCIENTIFIC REVIEWS
5.1

Study are described in a companion paper byBarratt et al. (1998) published along with the
Fentem et al. (1998) report. Based on the con­ditions under which the validation studies(Botham et al., 1995; Fentem et al., 1998) wereconducted, the PRP placed considerable weighton the results obtained and conclusions drawn
from these studies.

Literature reviewed

Three major reports are available on Corrositex®
in the open literature. Two of the reports(Botham et al., 1995; Fentem et al., 1998) pub­lished in peer-reviewed journals present resultsof validation studies. The Botham et al. (1995)
paper presents the results of a Prevalidation
Study conducted to determine if Corrositex® had
sufficient merit to warrant a validation study.
Based on the results, a validation study was sub­sequently performed and reported in the Fentem
et al. (1998) paper. The publication by Gordon
et al. (1994) describes results of Corrositex®
evaluations conducted by or for IVI or reported
to IVI. This paper was published as a chapter
of a book and was not peer-reviewed.

The study reported by Gordon et al. (1994)
evaluated 75 chemicals that could be classified
as to corrosivity based on published US DOTassigned packing group designations (49 CFR
172.101, 1992). The report also summarizes
the results of several previously conducted
Corrositex® studies of agrochemicals, petro­chemicals, and household cleaners. Specificdetails on the conduct of these studies with re­spect to laboratories used, GLP compliance,
criteria for selection of chemicals and full iden­tification of the chemical evaluated were notprovided. Most importantly, corresponding invivo data were not available to make the appro­
priate performance comparisons; thus, the PRP
did not use these data in the evaluation of per­formance.

The Prevalidation Study (Botham et al., 1995)
conducted during 1993 and 1994 involved theevaluation of 50 chemicals, half of which were
corrosive and half of which were noncorrosive.
Selection of these chemicals for testing was
based on the availability of sufficient in vivo
data to allow the chemicals to be unambiguouslyclassified. IVI was one of the two participating
laboratories. The subsequent ECVAM Valida­tion Study (Fentem et al., 1998) was conductedduring 1996 and 1997 and involved the evalua­tion of 60 coded chemicals representing a di­verse group of chemical classes, including or­
ganic acids, organic bases, neutral organics, in­organic acids, inorganic bases, inorganic salts,
electrophiles, phenols, and soaps/detergents.
The Validation Study was conducted in threelaboratories. Both studies, with the exceptionof one laboratory in the Prevalidation Study,
were conducted in the “spirit” of GLP. Welldefined criteria for the selection of the chemi­cals evaluated and clear objectives of the vali­
dations were established. The selection and dis­tribution of the chemicals for the Validation

Test results on some of the chemicals and chemi­
cal mixtures evaluated in the above-mentioned
papers were also submitted by IVI among the
118 chemicals comprising the Submission. Thisoverlap with data reported in the validation stud­ies consists of two of the 37 qualifying chemi­cals from the Prevalidation Study (Botham etal., 1995), and 32 of the 40 qualifying chemi­cals from the ECVAM Validation Study (Fentem
et al., 1998); however, only nine of these 32
chemicals were independently tested by IVI.
Nine of the 75 chemicals in the Gordon et al.
(1994) report were also included in the Submis­
sion, along with the corresponding in vivo datacompiled by IVI.

49

Corrositex® Evaluation

Other Scientific Reviews

5.2

the validation studies than for the Submission(19- 29% versus 8%). False positive and nega­tive rates were 0% and 3%, respectively, in theGordon et al. (1994) study.

Comparison of the findings of the
published studies and the Submission

Both the validation studies (Botham et al., 1995;
Fentem et al., 1998) and the Submission agreewith respect to repeatability. In thePrevalidation Study reported by Botham et al.
(1995), the data were sufficiently reproducible,
both in terms of individual breakthrough times
and the corrosivity classification derived, for thetwo laboratories that performed Corrositex®. In
the Validation Study reported by Fentem et al.
(1998), the intra- and inter-laboratory reproduc­
ibility was sufficient.

With regard to the utilization/functionality ofCorrositex® for specific classes of chemicals,
agreement between the two validation studies(Botham et al., 1995; Fentem et al., 1998) andthe Submission was variable with respect toaccuracy due to differences in results obtained
between the two validation studies. However,for the classes of chemicals and chemical mix­tures tested, the performance values between the
Submission and at least one of the two valida­tion studies were relatively similar. Differencesin accuracy between the studies are possibly the
result of the relatively small number of chemi­cals that comprised a chemical class, particu­
larly as this relates to noncorrosives. Becauseof the small numbers of chemicals and chemi­
cal mixtures evaluated, a single missed predic­
tion greatly shifts the percent accuracy value.
The small number of chemicals and chemical
mixtures evaluated for certain classes of chemi­cals also weakens any comparison of sensitiv­
ity, specificity, and false positive and negative
rates for specific classes of chemicals between
the validation studies and the Submission. How­ever, there appears to be sufficient information
to conclude that the false negative rate for ac­
ids and bases was higher in the two validation(Botham et al., 1995; Fentem et al., 1998) stud­ies than in the Submission (21-23% versus 7%).
ECVAM concluded that Corrositex® may bevalid for testing specific classes of chemicals
such as organic bases and inorganic acids. There
was insufficient chemical class information in
the Gordon et al. (1994) study for a reliable
comparison with the Submission.

For both of the laboratories in the Prevalidation
Study (Botham et al, 1995), 76% and 73%, re­spectively, of the chemicals qualified forCorrositex®. Similarly, 60% of the chemicals
and chemical mixtures in the Validation Study(Fentem et al., 1998) qualified for testing. A
much higher percentage of noncorrosives (60%)
failed to qualify than corrosives (10%). Over­
all, there is adequate agreement between thevalidation studies and the IVI Submission in
results obtained for chemicals that qualified forevaluation with Corrositex®. Accuracy is simi­
lar between the validation studies (75-76%) andthe Submission (82%). Gordon et al. (1994)
reported a much higher accuracy of 97%, which
may be due to the test chemicals and chemical
mixtures selected for evaluation. Sensitivity
was about 71% in the ECVAM Validation Studybut, in the Prevalidation Study, it was closer(81%) to the 92% reported in the Submission.
Specificity was similar for both thePrevalidation Study and the Submission at about
70%. Specificity was slightly higher for the
ECVAM Validation Study (81%). Sensitivity
and specificity in the Gordon et al. (1994) study
were at 97% and 100%, respectively. The vali­
dation studies and the Submission were gener­
ally similar relative to false positive rates. How­ever, false negative rates were much higher inRegarding the overall ability of Corrositex® toassign accurately chemicals to UN packing
groups, Gordon et al. (1994) indicates an agree­50

Corrositex® Evaluation

Other Scientific Reviews

ment of 88%, which is relatively close to the
IVI value of 80%. However, the Gordon et al.
(1994) study shows about equal occurrence ofoverestimates and underestimates, while theSubmission reported 20% overestimation and
2% underestimation. The ECVAM Validation
Study (Fentem et al., 1998) agrees with the Sub­mission in the limited ability of the method toassign correctly Packing Group I to the chemi­cals evaluated (about 50% and 60% for the
ECVAM Validation Study and the Submission,respectively). However, only about 62% of thechemicals and chemical mixtures were correctly
assigned to Packing Group II/Packing Group III
in the ECVAM Validation Study versus approxi­
mately 90% for the Submission.

ECVAM reported concern for the large numberof chemicals (40%) that did not qualify forevaluation with Corrositex®, considering this amajor limitation of Corrositex® as compared toother in vitro corrosivity assays. The concern
was especially significant for phenols, neutral
organics and electrophiles. ECVAM concluded
that Corrositex® is robust, readily available com­
mercially, and compares relatively well withother in vitro tests for corrosivity, the method
suffers because of its incompatibility with many
chemicals. ECVAM further concluded that
Corrositex® performs moderately well in its
ability to distinguish between corrosives andnoncorrosives for chemicals that qualify for thismethod.

51

52

6.0 OTHER CONSIDERATIONS
6.1.

6.1.3

Test method transferability

One of the most attractive features of this invitro test is its apparent ease of transfer amongproperly equipped and staffed laboratories. The
operating directions are explicit; data sheets areincluded; and there is a decision algorithm aspart of the test method. The test solutions andbiomembrane components are provided so thatthe issue of reagent variation is greatly mini­
mized. No information was provided on diffi­
culties in reconstituting the biomembrane; this
could be a source of variance.
6.1.1

Equipment, chemicals and chemical mixtures,and supplies needed to conduct this in vitro test
are readily available to end-users with a chemi­
cal laboratory, or could be readily obtained fromexisting commercial sources. The only limita­tion with respect to obtaining the needed equip­
ment and supplies might be the ability of theSponsor to provide the test kits. Use levels were
not predicted. However, the Sponsor indicatedthat they have a greater than ten-year supply of
biobarrier material.

Sensitivity to minor protocol changes
6.2

The method as described seems to have a num­
ber of steps at which changes in technique or
conditions between laboratories might affect theoutcome. However, considering the high levelof reproducibility for tests conducted in differ­
ent laboratories, this does not seem to be an is­sue. The results of testing to demonstrate theeffect of minor protocol changes was not pro­vided by IVI, nor was it addressed in either vali­
dation study.
6.1.2

Ease in obtaining necessary equipment
and supplies

Cost-effectivenessAt the Peer Review Meeting, the Sponsor quoted
a price of $575 for a kit to test two chemicals/
chemical mixtures, not including technical time.
Based on this price, two chemicals would betested by Corrositex® at a small cost savings
over an in vivo rabbit study. The commercial
price for the in vivo test is in the range of $800
to $1,000. This savings may be lost, if
Corrositex® is utilized in a tiered approach
where it would be required that findings using
Corrositex® need to be verified with a rabbit
study. However, fewer animals may need to betested following Corrositex® results.

Reasonableness of required training
and expertise

The testing is straightforward and does not re­quire extensive training. Indeed, the Corrositex®
Submission noted that after a two-hour training
session on the scientific background and direc­
tions for use of the test, a technician from an
end-user organization produced results with 20
test chemicals that showed 95% reproducibil­
ity with results obtained in the Sponsor’s ownlaboratory. Thus, based on the assay descrip­
tion, it would seem that a technician with a suit­able experience in chemistry would, with mod­est training, be able to handle the analyses well.

6.3

Reasonableness of time needed to con­duct the test

The time required was thought to be reasonable
by the PRP. Dr. Wei (IVI) stated at the Peer
Review Meeting that a reasonable workload for
one technician for one day would be eight toten chemicals. The only concern is whether atechnician can start successive test vials on thekind of schedule that will also allow accurate
reading of the breakthrough time.

53

Corrositex® Evaluation

Other Considerations

6.4

Additional information

6.6

The work of the PRP was impeded by the lackof a complete and organized collection of in­formation submitted to ICCVAM by IVI. This
made it difficult for the PRP to evaluate effi­
ciently the information provided. The Sponsor
also failed to supply a clear and concise state­ment of the proposed regulatory use of the test.
It must be noted that ICCVAM guidelines were
not available until after the Submission had been
submitted to ICCVAM. Future submissions to
ICCVAM will benefit from detailed guidance
for submission preparation (ICCVAM, 1998).
The descriptions of the test protocol could ben­efit from the addition of a flow diagram to il­lustrate the steps in the procedure, to accom­pany but not to replace the description. The
use of photographs to illustrate the procedure
also would help the novice analyst to become
adept at the assay. Information on the compo­
sition of the biobarrier, its source and stability,
within bounds of proprietary information, would
be helpful.
6.5

Comparison to current regulatory useof pH extremes

In the September 28, 1992 Application for Ex­
emption to the US DOT (IVI, 1992), IVI com­pared Corrositex® with a physico-chemical
method that uses pH and acid/alkali reserve to
predict dermal corrosivity; 19 acids and bases
diluted to different pH and acid/alkali reserve
were tested. The Sponsor reported that thephysico-chemical method underestimated thecorrosivity of six chemicals and overestimateda seventh. Corrositex® did not underestimate
any of the 19 chemicals used and overestimatedthe corrosivity of six. No other data were notedin the Submission regarding the use of pH ex­
tremes to classify chemicals. This sample is
too small to draw any useful conclusions about
the physico-chemical method.
If Corrositex® were to be endorsed as a valid
alternative to the rabbit test solely for identify­
ing corrosive inorganic and organic acid andbases, then the advantages of Corrositex® over
simple pH determination must be clearly stated.
In this respect, a comparison of the corrosive/
noncorrosive predictions obtained with either
Corrositex® or pH, for the 60 test chemicals usedin the ECVAM Validation Study (Fentem et al.,1998), showed that there were only three chemi­cals which would have been classified differ­
ently using Corrositex®: 2-methylbutyric acid(corrosive in vivo, corrosive with Corrositex®,
noncorrosive on the basis of pH),
dimethyldipropylenetriamine (corrosive in vivo,
corrosive with Corrositex®, noncorrosive on thebasis of pH), and 50% sodium carbonate (non­corrosive in vivo, corrosive with Corrositex®,
noncorrosive based on pH). In addition, 25 of
the 60 test chemicals were nonqualifying in the
Corrositex® assay and, of these, 21 would nothave invoked correct classification correctly
solely on the basis of pH.

Refinement, reduction, and replace­ment considerations

Since the method is designed as a replacement
for animals, the adoption of Corrositex® would
clearly reduce the requirement for animal test­
ing for corrosivity. Therefore, it has the poten­
tial to eliminate the use of animals for the de­termination of corrosivity for those chemicals
that can qualify for detection by this method.
However, Corrositex® does not meet criteria for
replacement of in vivo test in all evaluations
because of the limited number of chemicalclasses for which it is applicable as a stand-alone
assay. If used in a tiered approach, Corrositex®
provides for reduction and refinement of ani­
mal use. For chemicals that test negative or do
not qualify, these agents have a low likelihoodof causing corrosive lesions if tested in animals(refinement).
54

Corrositex® Evaluation

Other Considerations

A more detailed comparison of data for pH ex­
tremes and Corrositex® by NICEATM (Appen­
dices I and K) showed both pH and Corrositex®
are adequate methods for identifying thecorrosivity of chemicals in the extreme pH
ranges (i.e., pH < 2 or pH > 11.5). However,Corrositex® was slightly but consistently moreaccurate than pH for predicting corrosivity atthe extreme pH ranges. Corrositex® correctly
identifies several noncorrosive chemicals in theextreme pH ranges that would be false positive
results if analyzed by pH only. A number ofchemicals in non-extreme pH ranges (pH >2 andpH <11.5) were identified as corrosive basedon in vivo results. Corrositex® correctly identi­
fied the majority of these agents as corrosive.
Also, Corrositex®, in contrast to a pH analysis,
can be used for specifying packing group des­ignations. Thus, it would appear that
Corrositex® offers advantages over determina­tion of pH extremes for the identification of
corrosives.
6.7

for the test. A major concern is that a high per­centage of chemicals and chemical mixtures
used in the validation studies did not qualify
for the test method. However, as a test to clas­
sify those chemicals and chemical mixtures thatdo qualify, Corrositex® appears to be reason­
ably robust. The analysis of chemicals andchemical mixtures that do not qualify will, ob­
viously, require another testing procedure.
This in vitro test is especially less effective forchemicals and chemical mixtures with a pH
between 5.0 and 8.5; chemicals and chemical
mixture in this range show a significant rate ofnonqualification because the CDS does notchange color in this pH range. Certain chemi­cals and chemical mixtures containing dilute
alkali, dilute sodium metasilicate, and a surfac­
tant showed elevated false positive rates. In­
dustrial cleaners have a high false positive rateand lubricants, refinery streams and kerosene
additives were usually nonqualifying (Gordon
et al. 1994).

Effectiveness for assessing corrosivity/
noncorrosivity

The method appears to be reliable for thosechemicals and chemical mixtures that qualify

55

56

7.0 RELATED ISSUES
7.1

7.2.

Other test methods for this endpoint,
or other endpoints to be evaluated by
ICCVAM

Suggestions/recommendations forcorrosivity-related workshops or vali­
dation efforts

It was suggested that ICCVAM concentrate its
resources predominantly on endpoints otherthan skin corrosivity. However, a means ofachieving US regulatory authority acceptanceof the results of in vitro corrosivity studies con­ducted primarily in Europe could be to orga­
nize a workshop to discuss the rat skin TER and
EPISKIN assays, both of which were consid­
ered to be validated in the ECVAM Validation
Study (Fentem et al.,1998). Another possibil­
ity would be a workshop on how to assess labo­
ratory-to-laboratory variation for the validationof assays.

Other methods for consideration for this end­
point include the rat skin TER assay, and tests
using human skin models such as EPISKINTM
and EPIDERMTM. EPISKINTM and the rat skin
TER assay have been shown to be scientificallyvalid and have been recommended by ECVAM(Fentem et al., 1998).
In regard to validation assessments of other end­
points, several assays were suggested for con­sideration including: the neutral red uptake invitro phototoxicity assay, eye irritation assess­ments that incorporate in vitro cytotoxicity tests,
acute oral toxicity assessments using structure
activity relationships and in vitro methods, andassessment of dermal penetration models.

57

58

8.0 SUMMARY CONCLUSIONS AND RECOMMENDATIONS
Passage through these layers is observed by acolor change in the CDS, an underlying aque­ous solution of two pH indicator dyes. The timerequired to pass through the matrix is used as ameasure of the corrosive potential of the chemi­
cal or chemical mixture under test. The Sub­mission contained a thorough protocol. The
scientific basis of the test was generally de­scribed in sufficient detail. Corrositex® is cor­
relative in nature, rather than mechanistic. The
matrix was engineered to block passage of cer­tain chemicals and chemical mixtures for a pe­
riod of time similar to the time allowed for thatchemical or chemical mixture to stay in contact
with rabbit skin without causing “necrosis or
ulceration.” While an acellular matrix mightulcerate, it cannot undergo necrosis. The doseand breakthrough time selection procedures
were considered to be appropriate. Both were
established as a result of the extensive evalua­tion of corrosive and noncorrosive chemicals
and chemical mixtures and of knowledge gained
through Prevalidation and Validation Studies.
The amount of test chemical or chemical mix­
ture used in Corrositex® is the same as thosespecified for the animal studies, but the actual
concentration per unit surface area is approxi­
mately 8.5-fold higher. The qualification testwith the CDS provides a number of benefits tothe assay. It immediately eliminates chemicals
and chemical mixtures that do not qualify forthe test. It also provides the operator with aclear indication of the expected color changethat the test chemical or chemical mixture would
produce upon breakthrough of the biobarrier.
The descriptions of data collection, data evalu­
ation, and the decision criteria used to identify
chemicals and chemical mixtures as qualifying
or nonqualifying, Category 1 or 2, and corro­
sive or noncorrosive are well documented. The
Corrositex® protocol provides for both positive
and negative controls. The role of these con­trols is to assure that the test system is working

The PRP has evaluated the extensive body of
information on Corrositex®, in support of a re­quest in the Submission that this assay be evalu­
ated as an in vitro alternative to in vivo methods
employed to assess dermal corrosivity.
Corrositex® has been subjected to a series of
intra- and inter-laboratory validation studies inwhich its reliability and relevance have been
examined. The data set from the Submission
and the two validation studies included 163 pri­mary chemicals and chemical mixtures forwhich there were corresponding in vivo rabbit
corrosivity data. Data on 118 chemicals andchemical mixtures were provided by IVI, whiledata on 77 chemicals and chemical mixtures
were obtained from two peer-reviewed publi­
cations that evaluated the validity of Corrositex®
(Botham et al., 1995; Fentem et al., 1998).
There was overlap for 32 chemicals and chemi­
cal mixtures between IVI and the two valida­tion studies (Botham et al., 1995; Fentem et al.,1998). Corrositex® data provided in Gordon etal. (1994) were not included in the overall per­formance assessment since the Corrositex® re­sponses were compared against US DOTassigned packing group designations instead ofin vivo data. However, these data were provided
for comparative purposes.
This review includes a description of the test
method and an evaluation of data quality, assay
performance, and assay reliability, as well asother considerations. Also, the adequacy of themethod description, limitations and conditionsof the assay, and its relevance to in vivo studies
have been addressed.
8.1

Test method description

Corrositex® measures the time required for achemical or chemical mixture to pass a hydrated
collagen matrix and supporting filter membrane.
59Corrositex® Evaluation

Summary Conclusions and Recommendations

properly during each trial. Corrositex® does notmake provision for determining the irritancy ofnoncorrosives nor does it make any such claim.

sions. Similarly, rigorous checks of all calcula­tions, data analyses, etc, were conducted inde­
pendently by ECVAM staff and the Manage­
ment Team representatives of the lead labora­
tories.

The following specific changes to the protocol
were recommended:(1)

It should be explicitly stated that thebiobarrier should be allowed to harden
on a level surface and to cool overnight
before use.

(2)

Even though replicate variability has
been shown to be very low, guidanceshould be provided on how to evaluate
an aberrant value.

(3)

The IVI Corrositex® Data Sheets pro­vided with the test kit should have a pro­vision for recording the performance ofthe positive and negative controls.
These data should be used to determine
the suitability of the test results.

IVI used a consistent protocol when generating
the data included in the Submission. The data
resulting from the validation studies (Botham
et al., 1995; Fentem et al., 1998) followed an
established protocol that differed only slightly.
The differences noted did not invalidate thestudies conducted by IVI or the laboratories par­ticipating in the validation studies. The PRPurged compliance with GLP guidelines in fu­
ture studies to improve data quality and cred­ibility.
The PRP recommended that positive and nega­tive control values should be reported concur­
rently with each assay to determine if the test is
working properly.
8.3

(4)

8.2

Description of the test protocol would
benefit from the addition of a flow dia­gram illustrating the steps in the proce­dure.

Test method performance

Compared to in vivo rabbit skin corrosivity test
results, this in vitro test had a sensitivity of 85%(76/89), specificity of 70% (52/74), and accu­racy of 79% (128/163) for the chemicals andchemical mixtures provided in the Submission
and the two validation studies (Botham et al.,
1995; Fentem et al., 1998). The three data sets
reviewed (Submission; Botham et al., 1995;
Fentem et al., 1998) showed a similar degree ofsensitivity, specificity, and accuracy.

Test method data quality

The IVI in vitro and in vivo experiments were
not conducted in accordance with GLP guide­lines. However, audits were conducted by
NICEATM and by the NTP QAU; the audits
compared the data provided in the Submission
against original study records to verify accu­racy and completeness. The auditors concluded
that the errors and omissions identified did notalter the credibility of the IVI database. A for­mal audit of the ECVAM data conducted by a
QAU was not conducted; however, all data sub­mitted by the participating laboratories wereverified against the original data sheets by
ECVAM staff on at least three separate occa­

When considered by chemical or product class,the sensitivity, specificity, and accuracy ofCorrositex® were 79% (22/28), 63% (5/8), and
75% (27/36), respectively, for inorganic and or­
ganic acids plus acid mixtures; 100% (7/7), 86%(6/7), and 93% (13/14), respectively, for acidderivatives; 84% (16/19), 67% (4/6), and 80%(20/25), respectively, for amines; 89% (25/28),
57% (4/7), and 83% (29/35), respectively, for60

Corrositex® Evaluation

Summary Conclusions and Recommendations

inorganic and organic bases plus base mixtures;
86% (54/63), 68% (15/22), and 81% (69/85),
respectively, for organic and inorganic acids andbases; 90% (9/10), 29% (4/14), and 54% (13/24), respectively, for cleaners and detergents;
and 87% (13/15), 62% (8/13), and 75% (21/28),
respectively, for undefined industrial chemicals.
The specificity of Corrositex® for surfactants
was 100% (22/22); no corrosive surfactants
were tested.

The reproducibility of Corrositex® is expected
to be better than that of most biological tests,
since Corrositex® involves a standardized
physico-chemical test system rather than a bio­
logical endpoint. It is impossible to compare
directly the reproducibility of the in vitro test
and animal tests due to the lack of objective in­formation on the intra- and inter-laboratory re­producibility of the rabbit skin corrosivity test
procedure.

The demonstrated linkage between Corrositex®
and the in vivo rabbit skin corrosivity test is theability of the assay to correctly identify in vivo
rabbit corrosive and noncorrosive compounds.
The generally favorable accuracy analysis of thein vitro data with the in vivo test results sup­ports such a linkage. The assay is highly pH
and reserve acidity and alkalinity sensitive (i.e.,the more acidic or basic the chemical or chemi­
cal mixture, the more likely it is to give an ac­
curate prediction). This is consistent with what
is known about the in vivo dermal corrosion
potential of a chemical or chemical mixture.
The overall accuracy and the positive and nega­tive predictivity indicate that Corrositex® showsa fair degree of agreement with the in vivo test.
Corrositex® appears to perform better with cer­tain classes of chemicals than with other chemi­
cal classes.

The evaluations of intra- and inter-laboratory
reproducibility are generally thought to be ad­equate. Further relevant information could be
generated by analyzing existing data on posi­tive and negative controls, and by conducting
ANOVA. Using a weight-of-evidence ap­
proach, including data from the published vali­
dation studies (Botham et al., 1995; Fentem etal., 1998) as well as those reported in the Sub­mission, it appears that the intra- and inter-labo­
ratory reproducibilities are acceptable. How­ever, one reviewer felt that insufficient data wereavailable from independent laboratories to fully
evaluate interlaboratory reproducibility.
The PRP suggested that laboratories unfamiliar
with conducting the test should obtain appro­
priate training and conduct tests with test refer­ence chemicals before undertaking any testingof unknown chemicals and chemical mixtures.

Because of the relatively small numbers ofchemicals evaluated in some chemical classes
and the unbalanced nature of corrosive versus
noncorrosive chemicals (corrosive>>noncor­
rosive), definitive conclusions as to the ad­equacy of Corrositex® for some classes ofchemicals are difficult to make with a high de­gree of confidence.
8.4

8.5

Other scientific reviews

The PRP believes that, for chemicals that quali­
fied for Corrositex®, the similarity in perfor­
mance of the data sets in the published evalua­tions of Corrositex®, particularly the validation
studies (Botham et al., 1995; Fentem et al.,1998) and the Submission, provide an indica­tion as to the overall ability of the assay to pre­dict correctly the corrosive and noncorrosive
potential of various chemical classes. However,
ECVAM found a higher degree of false nega­

Test method reliability

The results appear to be sufficiently repeatable
and reproducible, both within and between labo­
ratories.
61

Corrositex® Evaluation

Summary Conclusions and Recommendations

tive results for Corrositex® than indicated in the
Submission.
8.6

in the future to re-evaluate the agreement be­
tween pH and Corrositex ® in identifying
corrosivity.

Other considerations
8.7

One of the most attractive features ofCorrositex® is its apparent ease of transfer
among properly equipped and staffed laborato­ries. Furthermore, slight changes in techniqueor conditions do not appear to affect test out­
come. Extensive training is not required, andequipment and supplies are readily accessible.
The cost of the Corrositex® test kit is less thanthe usual cost of an in vivo assay. The PRP notedthat the evaluation was impeded by the lack of
a complete and organized collection of data sub­mitted to ICCVAM by IVI.

Related issues

Other methods for consideration for this end­
point include the rat skin TER assay and tests
using human skin models, such as EPISKINTM
and EPIDERMTM.
A means of achieving US regulatory authority
acceptance to the results of in vitro corrosivity
studies conducted primarily in Europe could beto organize a workshop to discuss the rat skin
TER assay and EPISKINTM assay, both of whichwere considered validated in the ECVAM Vali­
dation Study (Fentem et al., 1998). Anotherpossibility would be a workshop assessing how
to evaluate laboratory-to-laboratory variation
for the validation of assays.

A more detailed comparison of data for pH ex­
tremes and Corrositex® by NICEATM (Appen­
dices I and K) showed both pH and Corrositex®
are adequate methods for identifying thecorrosivity of chemicals in the extreme pH
ranges (i.e., pH < 2 or pH > 11.5). Corrositex®
was slightly but consistently more accurate thanpH for predicting corrosivity at the extreme pH
ranges. Corrositex® correctly identified several
noncorrosive chemicals in the extreme pH
ranges that would be false positive results if
analyzed only by pH. A number of chemicals
in non-extreme pH ranges (pH >2 and pH <11.5)
were identified as corrosive based on in vivo
results. Corrositex® correctly identified the
majority of these agents as corrosive. Also,
Corrositex®, in contrast to the pH extreme, canbe used for specifying packing group designa­
tions. Thus, it would appear that Corrositex®
offers advantages over determination of pH ex­
tremes for the identification of corrosives.

In regard to validation assessments of other end­
points, several suggestions of other assays toconsider were made including: the neutral red
uptake in vitro phototoxicity assay, eye irrita­tion assessments that incorporate in vitro cyto­
toxicity tests, acute oral toxicity assessments
using structure activity relationships and in vitro
methods, and assessment of dermal penetration
models.
8.8

Has Corrositex® been evaluated suffi­
ciently and is its performance satisfac­
tory to support its proposed use for as­
sessing corrosivity potential of chemi­cals or chemical mixtures?

Corrositex® is limited in its universal utility
because of the proportion of chemicals that are
not compatible with the CDS and thus cannot
be evaluated. Corrositex® performance indi­cates that, in specific testing circumstances suchas that required by US DOT, Corrositex® is use­

Given the ease and cost effectiveness of con­ducting a pH test, the PRP recommended that
pH testing be conducted prior to use of theCorrositex®. Such information could be used

62

Corrositex® Evaluation

Summary Conclusions and Recommendations

8.10

ful as a stand-alone assay for evaluating thecorrosivity or noncorrosivity of acids, bases, andacid derivatives. The current US DOT exemp­tion allows the use of Corrositex® for assigning
packing groups for acids, acid derivatives, acyl
halides, alkylamines and polyalkylamines,
bases, chlorosilanes, metal halides, andoxyhalides. However, the database evaluatedby the PRP did not include acyl halides,
chlorosilanes, metal halides, or oxyhalides; thus
no statement can be made by the PRP for thesechemical classes. In other testing circum­
stances, and for other chemical and productclasses, Corrositex® may be more appropriately
used as part of a tiered assessment, in which
negative responses must be followed by dermal
irritation testing, and positive responses require
no further testing unless the investigator is con­cerned about potential false positive responses.
In either testing strategy, an investigator may
conclude that confirmation testing is necessary
based on supplemental information. As addi­
tional test results with Corrositex® are obtained,
the utility of the assay may need to be reconsid­
ered.
8.9

Advantages of Corrositex®

The advantage of the Corrositex® method is that
it is a non-animal test that can be used to evalu­
ate the skin corrosive potential of selectedclasses of chemicals and chemical mixtures andas a basis for setting priorities for further test­
ing, if necessary. The method demonstrates
sufficient inter- and intra-laboratory reproduc­
ibility. The method has the additional advan­
tage that large numbers of chemicals and chemi­
cal mixtures can be tested quickly and relatively
simply in a standard chemical laboratory set­
ting.
8.11

Limitations of Corrositex®

The false positive rate for Corrositex® is higher
than may be desirable for some classes of chemi­cals. The overall false positive rate for the da­tabase evaluated was 30% (22/74) and the cor­
responding false negative rate was 15% (13/89).
The in vivo method and the corresponding ref­erence data set also have inherent limitations.
However, the in vivo method is accepted by theregulatory agencies and is the current standard
against which all corrosivity alternative tests aremeasured.

Does Corrositex® offer advantages withrespect to animal welfare consider­ations (refinement, reduction, and re­placement alternatives)?

The principal limitation of the method is thelarge proportion of test chemicals and chemical
mixtures that do not qualify to be tested byCorrositex®. For the 1998 Submission, IVI was
instructed to only provide data on qualified
samples. The ECVAM Validation Study(Fentem et al., 1998) found that 37% of thechemicals (22 of 60) selected for evaluation did
not qualify for Corrositex®. That is, the chemi­
cal or chemical mixture was not capable of in­ducing a color change in the CDS so that the
breakthrough of the chemical or chemical mix­
ture through the biobarrier could be detected.
Of the total data set evaluated, including the1996 Submission, a total of 92 nonqualifiersCorrositex® was developed as a laboratory al­
ternative to the in vivo methods that are com­monly employed to assess dermal corrosivity.
The method does not meet the criteria for a to­tal replacement of the in vivo test because of
the limited number of chemical classes forwhich it is applicable. The use of Corrositex®
as a stand-alone assay for testing acids and bases
reduces and replaces the use of animals incorrosivity testing. Similarly, use of Corrositex®
as a component of a tiered approach for testingother chemical and product classes reduces andrefines the use of animals in testing.

63

Corrositex® Evaluation

Summary Conclusions and Recommendations

the results for many such chemicals and chemi­
cal mixtures were comparable to the in vivo re­sults, in the absence of composition data, noconfidence could be placed in the predictive
value of the test as compared with its correla­tive value.

were found. The majority of nonqualifiers havea pH between three and ten. Of the 75
nonqualifying chemicals for which in vivo data
were available, 64 chemicals (85%) were clas­sified as noncorrosive in the in vivo test. This
would suggest that only 15% of nonqualifying
chemicals or chemical mixtures would be ex­pected to be corrosive. Other in vitro methods
for corrosivity have not shown the same limita­tion with respect to the qualification of test
chemicals and chemical mixtures that have beenfound with Corrositex® (Fentem et al., 1998).
Examples of other in vitro methods forcorrosivity include the rat skin TER assay andthe EPISKINTM assay.

Another limitation or condition related to theevaluation of Corrositex® is the relatively small
number of chemicals evaluated in some chemi­
cal classes. The small number of chemicals andchemical mixtures and the unbalanced distribu­
tion of corrosive and noncorrosive chemicals
and chemical mixtures evaluated in each of sev­
eral chemical classes reduces the confidence as­sociated with any conclusions regarding the util­
ity of the method for all chemical classes.

In addition, no information was provided thatwould support the predictive value ofCorrositex® for complex mixtures. Although

64

REFERENCES
29 CFR 1917.28. 1998. Title 29: Occupational Safety and Health Administration. Code of Fed­
eral Regulations. Part 1917: Health Hazard Definitions (Mandatory). Section 28: Definition ofCorrosive. Government Printing Office, Washington, D.C. Available on the Internet, http://
www.osha-slc.gov/OshStd_data/1917_0028_APP_A.html.
40 CFR 158.690. 1992. Title 40: Protection of Environment. Code of Federal Regulations.
Chapter I: Environmental Protection Agency. Part 158: Data Requirements for Registration.
Section 690: Data Requirement Tables. Government Printing Office, Washington, D.C. Available
on the Internet, http://www.access.gpo.gov/nara/cfr/crf-table-search.html.
49 CFR 172.101. 1992. Chapter I: Research and special programs administration, Department ofTransportation. Code of Federal Regulations. Part 172: Hazardous materials table, special provi­sions, hazardous materials communications, emergency response information, and training require­ments. Section 101: Hazardous Materials Table. Government Printing Office, Washington, D.C.
49 CFR 173.137. 1992. Chapter I: Research and special programs administration, Department ofTransportation. Code of Federal Regulations. Part 173: Shippers—General requirements forshipments and packaging. Section 137: Class 8—Assignment of packing group. Government
Printing Office, Washington, D.C.
49 CFR 173 App. A. 1992. Chapter I: Research and special programs administration, Departmentof Transportation. Part 173: Shippers—General requirements for shipments and packaging. Ap­
pendix A to Part 173: Method of testing corrosion to skin. Government Printing Office, Washing­
ton, D.C.
Bagley, D. M., J. R. Gardner, G. Holland, R. W. Lewis, J.-F. Regnier, D. A. Stringer, and A. P.
Walker. 1996. Skin irritation: Reference chemicals data bank. Toxicol. In Vitro 10:1-5.
Barratt, M. D., P. G. Brantom, J. H. Fentem, I. Gerner, A. P. Walker, and A. P. Worth. 1998. The
ECVAM international validation study on in vitro tests for skin corrosivity. 1. Selection and distri­bution of the test chemicals. Toxicol. In Vitro 12:471-482.
Botham, P. A., M. Chamberlain, M. D. Barratt, R. D. Curren, D. J. Esdaile, J. R. Gardner, V. C.
Gordon, B. Hildebrand, R. W. Lewis, M. Liebsch, P. Logemann, R. Osborne, M. Ponec, J.-F. Régnier,W. Steiling, A. P. Walker, and M. Balls. 1995. A prevalidation study on in vitro skin corrosivity
testing. The report and recommendations of ECVAM Workshop 6. ATLA 23: 219-255.
Dorland’s Illustrated Medical Dictionary. 1994. Definition of precision. 28th ed., W.B. SaundersCo., Philadelphia.
ECETOC (European Centre for Ecotoxicology and Toxicology of Chemicals). 1995. Technical
Report No.66, Skin Irritation and Corrosion: Reference Chemicals Data Bank, March.

65

Corrositex® Evaluation

References

Fentem, J. H., G. E. B. Archer, M. Balls, P. A. Botham, R. D. Curren, L. K. Earl, D. J. Esdaile, H.­
G. Holzhütter, and M. Liebsch. 1998. The ECVAM international validation study on in vitro tests
for skin corrosivity. 2. Results and evaluation by the management team. Toxicol. In Vitro 12:483­
524.
Gordon, V. C., J. D. Harvell, and H. I. Maibach. 1994. Dermal Corrosion, the Corrositex® System:
A DOT Accepted Method to Predict Corrosivity Potential of Test Materials. In: In Vitro Skin Toxi­
cology- Irritation, Phototoxicity, Sensitization. Alternative Methods in Toxicology. A. Rougier, A.
M. Goldberg , H. I Maibach, eds., Vol 10, pp. 37-45. Mary Ann Liebert, New York.
ICCVAM (Interagency Coordinating Committee on the Validation of Alternative Methods). 1998.
Evaluation of the validation status of toxicological methods: General guidelines for submissions to
ICCVAM (rev. May 22, 1998). Available on the Internet, http://iccvam.niehs. nih.gov/doc1.htm.
IVI (InVitro International, Inc.). 1992. Application for Exemption to 49 CFR 173.136 and 173.137.
Submitted to the United States Department of Transportation, Associate Administrator for Hazard­
ous Materials Safety, Washington, DC 20590-0001. Sept. 28.
NIEHS (National Institute of Environmental Health Sciences). 1997. Validation and regulatory
acceptance of toxicological test methods: A report of the ad hoc Interagency Coordinating Com­mittee on the Validation of Alternative Methods. NIH Publication No. 97-3981. NIEHS, Research
Triangle Park, NC. Available on the Internet, http://ntp-server.niehs.nih.gov/htdocs/ICCVAM/
iccvam.html.
OECD (Organisation for Economic Cooperation and Development). 1992. OECD guideline fortesting of chemicals 404: Acute dermal irritation/corrosion. OECD, Paris.
Purchase, F.H. 1982. An appraisal of predictive tests for carcinogenicity. Mutat. Res. 99:53-71.
US DOT (United States Department of Transportation). 1996. DOT-E 10904: Second Revision.
Exemption from US DOT Regulations 49 CFR 173.136(a)(1), 173.137(a), 173.137(b), and173.137(c)(1). US DOT Research and Special Programs Administration. Dec. 12. (A copy of thisexemption is provided in Appendix Q).
Weil, C. S., and R. A. Scala. 1971. Study of intra- and inter-laboratory variation in the results ofrabbit eye and skin irritation tests. Toxicol. Appl. Pharmacol. 19:276-360.

66

Appendix A

List of Chemicals Evaluated in Corrositex®
The list provided on the following pages is atabulation of all the chemicals that were evalu­
ated in the papers/documents referenced below.

• Barratt, M. D., P. G. Brantom, J. H. Fentem,
I. Gerner, A. P. Walker, and A. P. Worth.
1998. The ECVAM international validation
study for in vitro tests for skin corrosivity.
1. Selection and distribution of the test
chemicals. Toxicol. In Vitro 12:471-482.

• Botham, P. A., M. Chamberlain, M. D.
Barratt, R. D. Curren, D. J. Esdaile, J. R.
Gardner, V. C. Gordon, B. Hildebrand, R.
W. Lewis, M. Liebsch, P. Logemann, R.
Osborne, M. Ponec, J.-F. Régnier, W.
Steiling, A. P. Walker, and M. Balls. 1995.
A prevalidation study on in vitro skincorrosivity testing: The report and recom­
mendations of ECVAM Workshop 6. ATLA
23:219-255.

• Fentem, J. H., G. E. B. Archer, M. Balls, P.
A. Botham, R. D. Curren, L. K. Earl, D. J.

Esdaile, H.-G. Holzhütter, and M. Liebsch.
1998. The ECVAM international validation
study on in vitro tests for skin corrosivity.
2. Results and evaluation by the manage­
ment team. Toxicol. In Vitro 12:483-524.

• Gordon, V. C., J. D. Harvell, and H. I.
Maibach. 1994. Dermal corrosion, theCorrositex system: A DOT accepted method
to predict corrosivity potential of test mate­rials. Alternative Methods Toxicol. 10:37­
45.

• InVitro International, Inc. Corrositex®
ICCVAM Submission, May, 1998

Chemical/product class information was deter­
mined based on the information provided in thepapers/submission. Where such information
was not available, chemical/product class des­ignations were assigned by National Toxicol­
ogy Program (NTP) Interagency Center for the
Evaluation of Alternative Toxicological Meth­ods (NICEATM) staff member Bonnie Carson,
M.S., Organic Chemistry.

Appendix B

Characterization of the Data Sources (Appendix A) Used for Performance
Analyses of Corrositex® 1
Table 1. Number of qualifying chemicals overlapping between sources (based on the total
data set)
Total

IVI
submission(1998)
Fentem et al.
(1998)
Botham etal. (1995)
Gordon et al.
(1994)
Total Data
Set

Submission
IVI(1998)
submission(1998)

Fentem et al.
(1998)

Botham etal. (1995)

Gordon et al.
(1994)

32a

2b

9

1

2

118
40

32a

37

2b

1

75

9

2

8
8

221c

a

Data submitted by InVitro International (IVI) in the Submission for twenty-three chemicals wereobtained from the Fentem et al. (1998) Validation Study. Discordant Corrositex® results between
IVI and Fentem et al. (1998) were found for two chemicals (2,4-xylidine and hexanoic acid); bothwere classified as positive by IVI. These chemicals were considered as positive in the total data set
performance calculations. In the individual source data set calculations, neither of these chemicals
was included in the performance calculations of the Fentem et al. (1998) data set since they werediscordant between laboratories within the validation study. Discordant in vivo results between
source papers were found for one chemical (potassium hydroxide, 5% aq.). When this chemical
was included in the total data set calculations, it was considered to be positive. In the data sets forthe individual papers, the in vivo finding reported in the respective paper was used.
b

Discordant Corrositex® results between source papers were found for one chemical (hexanoicacid) (see footnote “a”). Discordant Corrositex® results between laboratories in the Botham et al.
(1995) paper were found for one compound (Empicol LZPV/C); this compound was not includedin the performance calculations for this paper.
cThis total is less than the sum of the chemicals reported in the individual papers because of theoverlap in chemicals reported in multiple papers. This total was derived from the following:• number of chemicals reported in a single paper = 174 (includes one compound [2,4-xyli­dine] actually reported in two papers but only included in calculations for one paper due todiscordance [see footnote “a”]);

1

See tables 5-14

B-1

Appendix B: Characterization of Data Sources• number of chemicals reported in two papers = 45 (includes one compound [hexanoic acid]actually reported in three papers but only included in calculations for two papers due todiscordance [see footnotes “a” and “b”]); and• number of chemicals reported in three papers = 2.

B-2

Appendix C

Corrositex® Test Method Submission (May, 1998)
EXECUTIVE SUMMARY
InVitro International’s Corrositex® test is a laboratory alternative to the in vivo methods
that are commonly employed to assess dermal corrosivity. Previous investigations havedemonstrated the utility of this in vitro method and it is now accepted by the U.S.
Department of Transportation (DOT E-10904) as a satisfactory means of defining thecorrosivity of Class 8 hazardous materials.
In addition, EPA has approved Corrositex as Method 1120 for the characterization ofsolid waste.
In early 1996, at the request of the chairman of the Consumer Product Safety
Commission, the Interagency Coordinating Committee for the Validation of Alternative
Methods (ICCVAM) performed an initial technical review of much of the available
Corrositex data. This review resulted in a request for additional information andclarification. InVitro International responded in June 1996 and provided the requested
information with a data base consisting of 419 individual chemicals and compounds.
However, a lot of the materials included in that data base can not be identified. Therefore,
notebook copies of these data points can not be located. A new table with 118 chemicals
and compounds is constructed and evaluated. This new table included the data points
that can be backed up with notebook copies and those from the ECVAM validation
study. Analysis of this revised information provided similar observations to the June
1996 submission:• The Corrositex test is comparable to the in vivo test with regard to its ability
to assess the corrosivity of well-defined inorganic and organic acids and bases.
• The Corrositex test is comparable to the in vivo test with regard to its ability
to assess the corrosivity of complex mixtures of inorganic and organic acids
and bases.
• As judged by sensitivity, specificity, false positive rates, and false negative
rates, the Corrositex test tends to “err on the side of safety.”• The Corrositex test appears to exhibit an increased false positive rate forindustrial cleaner formulations, i.e., mixtures composed of dilute alkali, dilute
sodium metasilicate, and a surfactant. This over-estimation of corrosivity
tends to favor public safety.
Taken together, these observations suggest that the Corrositex test, as defined by theparameters embodied in DOT E-10904, is a very suitable and safe in vitro alternative tothe in vivo methods that are employed to assess the dermal corrosivity of hazardous
materials. We ask for regulatory support where Corrositex has been proven to work well;and that it not be held back because there may be some areas where Corrositex does notwork as well.

C-1

Appendix C: Corrositex® Test Method Submission (May, 1998)

Figure 2. Diffusion Times and Acid/Base Strength Govern “Breakthrough” Times

C-2

Appendix C: Corrositex® Test Method Submission (May, 1998)

2. Describe how use of Corrositex will produce results that are at least equivalent forrisk assessment purposes as the method that it is proposed to replace. In particular, thepredicted frequency and implications of false negatives and false positives should be
addressed.
The new database, which contained a description of 118 distinct samples (Appendix
IV), was employed as the primary source of information for this response. The 2X2
contingency table is shown below.

In Vivo Results

Corrositex
Results

Corrosive

Noncorrosive

Total

Corrosive

59

16

75

Noncorrosive

5

38

43

Total

64

54

118

Table 1. Comparison of Corrositex Results with In Vivo Results.
These observations were analyzed further by performing the calculations shown in
Table 2 shown below.
Parameter
Equivalence =FormulaNumber of Compounds Correctly Identified

Results= 97/118 = 82%

Total Number of Compounds Tested
Sensitivity =Number of Corrosives Correctly Identified= 59/64 = 92%

Total Number of Corrosives
Specificity =Number of Noncorrosives Correctly Identified= 38/54 = 70%

Total Number of Noncorrosives
Predictive Value =Number of Corrosives Correctly Identified(Corrosives)

Total Number of Corrosive Results

Predictive Value =(Noncorrosives)

Number of Noncorrosives Correctly Identified

False Positive
Rate =
False Negative
Rate == 59/75 = 79%= 38/43 = 88%

Total Number of Noncorrosive Results
Number of Noncorrosives Classified as Corrosive= 16/54 = 30%

Total Number of Noncorrosives Tested
Number of Corrosives Classified as Noncorrosive
Total Number of Corrosives Tested= 5/64 = 8%

Table 2. Summary of the Performance of the Corrositex Test Compared to In Vivo Findings
C-3

Appendix C: Corrositex® Test Method Submission (May, 1998)

Table 2. Summary of the Performance of the Corrositex Test Compared to In Vivo
Findings
These findings demonstrate that the Corrositex test correlates well with the acceptedin vivo method of assessing dermal corrosivity. The sensitivity and specificity of thelaboratory test favors identification of corrosive substances. This observation is also
substantiated by noting that the false positive rate is greater than the false negative
rate. All of these observations are consistent with the stated developmental objectiveof providing an in vitro test that tended to “err on the side of safety.”

3. Provide in vivo reference data including a description of the quality of the data,
protocol used to generate the data, the data from the tests, and a summary of the actual
results. The nature, quality, and source of any other in vivo reference data should be
provided. Describe the definition of corrosivity used in the in vivo tests, such as
ulceration, necrosis, or other specified irreversible change. Indicate if the in vivo data are
available for examination.
In vivo data are included in Appendix V for data audit purpose. The entire content ofAppendix V is confidential. The in vivo data are summarized together with Corrositex
data in Appendix IV. The protocol and definition of corrosivity are described inAppendix V.

4. Indicate if the Corrositex and in vivo data were generated in accordance with GLPs.
Describe those aspects that were not performed in accordance with GLPs, and thepotential impact of such deviations from non-adherence to GLPs.
Notebook copies for data points summarized in Appendix IV are included inAppendix VI for data audit purpose. The entire content of Appendix VI isconfidential. The scientific notebooks of InVitro International’s scientists andtechnicians are maintained on file at the company’s Irvine, CA facility. These
documents were reviewed during the preparation of this response and both the quality
and the quantity of the data contained in these records was found to be sufficient tosupport the current and prior applications. However, it was noted that strict
adherence to GLP was not maintained. For example, not all of the notebooks havebeen signed by the technician who performed the work or the technicians’ supervisor
and not all partially completed notebook pages have been lined out. In spite of this,the underlying data is sound and it is unlikely that these technical failures to comply
with GLP have a significant negative impact on the outcomes of the studies reported
here.

5. Indicate if laboratory records have been maintained for the testing that has been
conducted, and if these records would be available for examination if requested.

Laboratory records have been maintained for the testing that has been conducted. All ofthese records are available for on-site examination if requested.

C-4

Appendix C: Corrositex® Test Method Submission (May, 1998)

6. Indicate whether there are Corrositex testing data for the range of chemicals andproducts regulated by agencies that have or will be asked to accept this method, andindicate the specific classes of chemicals and products for which this method is being
proposed.
As noted in response to Question 1, the Corrositex test was specifically designed toassess the corrosivity of acids and bases. Consequently, the types of chemicals thathave been assessed to date have predominantly been those that are known to beconsistent with the DOT description of Class 8 corrosives. The current DOT
exemption (Appendix VII) indicates that the Corrositex test is suited for assessing thecorrosivity of the following classes of chemicals:• Acids, inorganic and organic• Acid derivatives (anhydride, haloacids, salts, etc.), inorganic and organic• Acyl halides• Alkylamines and polyalkylamines• Bases, inorganic and organic• Chlorosilanes• Metal halides and oxyhalides.

7. Develop 2X2 tables for each study showing the degree of agreement between the invitro and in vivo tests. This should include calculations for concordance, sensitivity,
specificity, false positive rate, false negative rate, and positive and negative predictivity.
Also, it is important to know, as a function of chemical class and product category, theproportion of discordant calls that were “under” and “over.”The revised data base consisting of 118 samples (Appendix IV) was sorted to identify
compounds and chemicals that could be assigned to defined classes. This resulted in adata base consisting of 63 materials (Appendix VIII). The remaining 55 compounds
consisted of mixtures and proprietary products that the composition is unknown.
These undefined compounds are compiled on a separate list found in Appendix IX.
Data found only in Appendix VIII was then utilized to develop the 2X2 contingency
tables and performance analysis for each chemical class as shown below.
When inorganic and organic acids as well as acid mixtures were delineated within
the data base found in Appendix VIII, the following results were obtained:
Total number of compounds: 22
C-5

Appendix C: Corrositex® Test Method Submission (May, 1998)

Contingency table:

In Vivo Results

Corrositex
Results

Corrosive

Noncorrosive

Total

Corrosive

15

2

17

Noncorrosive

2

3

5

Total

17

5

22

Table 3. Comparison of Corrositex Results with In Vivo Results for
Inorganic and Organic Acids and Acid Mixtures.
Performance summary:Parameter
Equivalence =FormulaNumber of Compounds Correctly Identified

Results= 18/22 = 82%

Total Number of Compounds Tested
Sensitivity =Number of Corrosives Correctly Identified= 15/17 = 88%

Total Number of Corrosives
Specificity =Number of Noncorrosives Correctly Identified= 3/5 = 60%

Total Number of Noncorrosives
Predictive Value =(Corrosives)

Number of Corrosives Correctly Identified

Predictive Value =(Noncorrosives)

Number of Noncorrosives Correctly Identified

False Positive

Number of Noncorrosives Classified as Corrosive
Total Number of Noncorrosives Tested= 2/5 = 40%

Number of Corrosives Classified as Noncorrosive
Total Number of Corrosives Tested= 2/17 = 12%

Rate =
False Negative
Rate == 15/17 = 88%

Total Number of Corrosive Results= 3/5 = 60%

Total Number of Noncorrosive Results

Table 4. Summary of the Performance of the Corrositex Test Compared to In Vivo
Findings for Inorganic and Organic Acids and Acid Mixtures

C-6

®
C: Corrositex
Test
Method Submission(May, 1998)
Table 4. Summary of the Performance Appendix
of the Corrositex
Test
Compared
to In Vivo
Findings for Inorganic and Organic Acids and Acid Mixtures.

When inorganic and organic acid derivatives were delineated within the data basefound in Appendix VIII, the following results were obtained:
Total number of compounds: 14
Contingency table:

In Vivo Results

Corrositex
Results

Corrosive

Noncorrosive

Total

Corrosive

7

1

8

Noncorrosive

0

6

6

Total

7

7

14

Table 5. Comparison of Corrositex Results with In Vivo Results for Acid Derivatives.
Performance summary:Parameter
Equivalence =FormulaNumber of Compounds Correctly Identified

Results= 13/14 = 93%

Total Number of Compounds Tested
Sensitivity =Number of Corrosives Correctly Identified= 7/7 = 100%

Total Number of Corrosives
Specificity =Number of Noncorrosives Correctly Identified= 6/7 = 86%

Total Number of Noncorrosives
Predictive Value =(Corrosives)

Number of Corrosives Correctly Identified

Predictive Value =(Noncorrosives)

Number of Noncorrosives Correctly Identified

False Positive= 1/7 = 14%

Rate =

Number of Noncorrosives Classified as Corrosive
Total Number of Noncorrosives Tested

False Negative

Number of Corrosives Classified as Noncorrosive= 0/7 = 0%

Rate == 7/8 = 88%

Total Number of Corrosive Results= 6/6 = 100%

Total Number of Noncorrosive Results

Total Number of Corrosives Tested

Table 6. Summary of the Performance of the Corrositex Test Compared to In Vivo
Findings for Acid Derivatives.

C-7

Appendix C: Corrositex® Test Method Submission (May, 1998)

Table 6. Summary of the Performance of the Corrositex Test Compared to In Vivo
Findings for Acid Derivatives.

When amines were delineated within the data base found in Appendix VIII, thefollowing results were obtained:
Total number of compounds: 14

Contingency table:

In Vivo Results

Corrositex
Results

Corrosive

Noncorrosive

Total

Corrosive

10

0

10

Noncorrosive

1

3

4

Total

11

3

14

Table 7. Comparison of Corrositex Results with In Vivo Results for Amines.
Performance summary:Parameter
Equivalence =FormulaNumber of Compounds Correctly Identified

Results= 13/14 = 93%

Total Number of Compounds Tested
Sensitivity =Number of Corrosives Correctly Identified= 10/11 = 91%

Total Number of Corrosives
Specificity =Number of Noncorrosives Correctly Identified= 3/3 = 100%

Total Number of Noncorrosives
Predictive Value =(Corrosives)

Number of Corrosives Correctly Identified

Predictive Value =(Noncorrosives)

Number of Noncorrosives Correctly Identified

False Positive
Rate =
False Negative
Rate == 10/10 = 100%

Total Number of Corrosive Results= 3/4 = 75%

Total Number of Noncorrosive Results
Number of Noncorrosives Classified as Corrosive
Total Number of Noncorrosives Tested= 0/3 = 0%

Number of Corrosives Classified as Noncorrosive
Total Number of Corrosives Tested= 1/11 = 9%

Table 8. Summary of the Performance of the Corrositex Test Compared to In Vivo
Findings for Amines.
C-8

Appendix C: Corrositex® Test Method Submission (May, 1998)

Table 8. Summary of the Performance of the Corrositex Test Compared to In Vivo
Findings for Amines.
When inorganic bases and base mixtures were delineated within the data basefound in Appendix VIII, the following results were obtained:
Total number of compounds: 8Contingency table:

In Vivo Results

Corrositex
Results

Corrosive

Noncorrosive

Total

Corrosive

7

1

8

Noncorrosive

0

0

0

Total

7

1

8

Table 9. Comparison of Corrositex Results with In Vivo Results for
Inorganic Bases and Base Mixtures.
Performance summary:Parameter
Equivalence =FormulaNumber of Compounds Correctly Identified

Results= 7/8 = 88%

Total Number of Compounds Tested
Sensitivity =Number of Corrosives Correctly Identified= 7/7 = 100%

Total Number of Corrosives
Specificity =Number of Noncorrosives Correctly Identified= 0/1 = 0%

Total Number of Noncorrosives
Predictive Value =(Corrosives)

Number of Corrosives Correctly Identified

Predictive Value =(Noncorrosives)

Number of Noncorrosives Correctly Identified= 7/8 = 88%

Total Number of Corrosive Results= 0/0 = N/A

Total Number of Noncorrosive Results= 1/1 = 100%Rate =

Number of Noncorrosives Classified as Corrosive
Total Number of Noncorrosives Tested

False Negative

Number of Corrosives Classified as Noncorrosive= 0/7 = 0%

False Positive

Rate =

Total Number of Corrosives Tested

Table 10. Summary of the Performance of the Corrositex Test Compared to In Vivo
Findings for Inorganic Bases and Base Mixtures.
C-9

Appendix C: Corrositex® Test Method Submission (May, 1998)

The remaining of Appendix VIII are Cinnamaldehye, Trichlorotoluene, 20/80
Coconut/Palm Soap, Sodium Undecylenate, and Cellusolve + TX-100. The following
results were obtained:
Total number of compounds: 5

Contingency table:

In Vivo Results

Corrositex
Results

Corrosive

Noncorrosive

Total

Corrosive000Noncorrosive

0

5

5

Total

0

5

5

Table 11. Comparison of Corrositex Results with In Vivo Results for theremaining of Appendix VIII.
A performance summary was not prepared.

An interesting way of summarizing this data is suggested by the knowledge that theCorrositex Chemical Detection Solution is composed of an aqueous solution of anacidic indicator dye (methyl orange) and a basic indicator dye (phenyl red). As aresult, the Corrositex test would be expected to perform most reliably as a means ofcharacterizing the dermal corrosivity of acids and bases. Therefore, the acid and basedata from Tables 3, 5, 7, and 9 presented above have been compiled and are presented
below in Table 12.

In Vivo Results

Corrositex
Results

Corrosive

Noncorrosive

Total

Corrosive

39

4

43

Noncorrosive

3

12

15

Total

42

16

58

Table 12. Comparison of Corrositex Results with In Vivo Results for
Organic and Inorganic Acids and Bases.
C-10

Appendix C: Corrositex® Test Method Submission (May, 1998)

Table 12. Comparison of Corrositex Results with In Vivo Results for
Organic and Inorganic Acids and Bases.
The performance of the Corrositex test for organic and inorganic acids and bases may
then be calculated as follows:

Parameter
Equivalence =FormulaNumber of Compounds Correctly Identified

Results= 51/58 = 88%

Total Number of Compounds Tested
Sensitivity =Number of Corrosives Correctly Identified= 39/42 = 93%

Total Number of Corrosives
Specificity =Number of Noncorrosives Correctly Identified= 12/16 = 75%

Total Number of Noncorrosives
Predictive Value =(Corrosives)

Number of Corrosives Correctly Identified

Predictive Value =(Noncorrosives)

Number of Noncorrosives Correctly Identified

False Positive

Number of Noncorrosives Classified as Corrosive
Total Number of Noncorrosives Tested= 4/16 = 25%

Number of Corrosives Classified as Noncorrosive
Total Number of Corrosives Tested= 3/42= 7%

Rate =
False Negative
Rate == 39/43 = 91%

Total Number of Corrosive Results= 12/15 = 80%

Total Number of Noncorrosive Results

Table 13. Summary of the Performance of the Corrositex Test Compared to In Vivo
Findings for Inorganic and Organic Acids and Bases.
The results reported here suggest that, for acids and bases, the Corrositex test is very
comparable to the in vivo test of dermal corrosivity. In addition, with regard to corrosive
materials, the Corrositex test displays excellent sensitivity and predictivity. The false
positive rate of the Corrositex test is much greater than the false negative rate. In theseregards, the results obtained with acids and bases display similar trends with thosereported for all of the compounds in our current data base (see Table 2, page 3).

C-11

Appendix C: Corrositex® Test Method Submission (May, 1998)

8. Indicate any limitations for the use of this method. Specify any chemical classes or
product categories where the method should or probably should not be used.
As detailed in response to Question 13 in Section A, current evidence suggests that
“industrial cleaners” tend to give an elevated false positive response rate in the
Corrositex test. Initial investigations indicate that most of these formulations appear
to be composed of a mixture of dilute (0.5 - 2.0%) alkali, dilute (0.5 - 5.0%) sodium
metasilicate, and a surfactant. However, this over-estimation of corrosivity tends tofavor public safety.
As noted in June 1996 submission, response to Question 2d in Section C, samples
that have a pH in the range of 5.0 to 8.5 display a significant rate of non-qualificationin the Corrositex test. This observation is consistent with the knowledge that the
CDS indicator solution does not exhibit a color change in this pH range.

9. Provide the complete detailed technical protocol for the proposed method.
A copy of the current Corrositex Instruction Manual (revision 12/95) is found in
Appendix X.

10. Provide the complete protocols used to generate the different sets of data included inthis submission. The technical protocol used, including any modifications and theirimpact, should be clearly stated for each data set.
The original version of the Corrositex Instruction Manual (revision 1/95) provides adetailed description of the experimental protocol that was employed for all of thestudies reported here. This version of the protocol is found in Appendix XI.

11. Submit quality assurance procedures used to ensure lot-to-lot consistency of the test
materials, and summarize data for such monitoring.
The current versions of the Quality Control Assessment SOPs for Corrositex
formulations and fully-assembled kits are found in Appendix XII. The results ofinitial lot-to-lot quality assurance studies can be found on pages 20 to 24 of the
Application for Exemption submitted on September 28, 1992 (Appendix I). To date,18 lots have been manufactured and all have passed the quality assurance
specifications listed in the Standard Operating Procedures (SOP) found in the
Appendix XII.

12. Data submission:a. Indicate which and if any of the studies were conducted with coded chemicals.
C-12

Appendix C: Corrositex® Test Method Submission (May, 1998)

The Application for Renewal of Exemption DOT E-10904 (Appendix II) contains
several tables that detail the results of studies conducted with coded samples. Table
14 shown on the next page summarizes the appropriate references for these tables:
Table Number

Page Number

Number of Coded Samples

17

34

29

38 and 39

66 and 67

50

53

118

17

Table 14 . Summary of Tables Found in Appendix II Describing Results of Studies
Conducted with Coded Samples.
Additionally, it should be noted that Tables 38 and 39 found in Appendix II contained
a series of misaligned cells. Consequently, the data presented there is incorrect.
These errors were corrected in the supplemental information provided in Appendix III(pages 13-21).

b. Indicate the timeframe of the conduct of the various studies; i.e., the dates during
which studies were conducted in each laboratory.
The data included in Appendix VI were obtained from April 1993 through June 1994.
The in vivo studies were conducted at various times as indicated in the reports(Appendix V).

c. Indicate the lab in which each data set was generated, even if this is provided as acoded designation for each lab.
The Corrositex results of the revised data base consisting of 118 samples weregenerated by InVitro International (Appendix VI). The in vivo results were generated
by the contract lab in L. A. or were supplied by the manufactures as shown inAppendix V.

13. Provide the chemical composition for chemical mixtures and products included in thedata submission. Data for mixtures or products for which the chemical composition is
not known or available should be evaluated separately from chemicals for which thisinformation is available.
The composition of 63 materials found in the revised data base (Appendix IV) is known.
This information is summarized in Appendix VIII and has been evaluated and discussed in
response to Question 7. The composition of the remaining 55 materials is proprietary
and is unknown. The results of studies conducted on these materials are summarized in
C-13

Appendix C: Corrositex® Test Method Submission (May, 1998)

Appendix IX and are utilized to develop the 2X2 contingency tables and performance
analysis for each product class as shown below.
When cleaners and detergents were delineated within the data base found in
Appendix IX, the following results were obtained:
Total number of compounds: 18
Contingency table:

In Vivo Results

Corrositex
Results

Corrosive

Noncorrosive

Total

Corrosive

7

7

14

Noncorrosive

1

3

4

Total

8

10

18

Table 15. Comparison of Corrositex Results with In Vivo Results for Cleaners andDetergents.
Performance summary:Parameter
Equivalence =FormulaNumber of Compounds Correctly Identified

Results= 10/18 = 56%

Total Number of Compounds Tested
Sensitivity =Number of Corrosives Correctly Identified= 7/8 = 88%

Total Number of Corrosives
Specificity =Number of Noncorrosives Correctly Identified= 3/10 = 30%

Total Number of Noncorrosives
Predictive Value =(Corrosives)

Number of Corrosives Correctly Identified

Predictive Value =(Noncorrosives)

Number of Noncorrosives Correctly Identified

False Positive
Rate =
False Negative
Rate == 7/14 = 50%

Total Number of Corrosive Results= 3/4 = 75%

Total Number of Noncorrosive Results
Number of Noncorrosives Classified as Corrosive
Total Number of Noncorrosives Tested= 7/10 = 70%

Number of Corrosives Classified as Noncorrosive
Total Number of Corrosives Tested= 1/8 = 12%

Table 16. Summary of the Performance of the Corrositex Test Compared to In Vivo
Findings for Cleaners and Detergents.
C-14

®

C: CorrositexTest
TestCompared
Method Submission(May, 1998)
Table 16. Summary of the PerformanceAppendix
of the Corrositex
to In Vivo
Findings for Cleaners and Detergents.

When industrial chemical were delineated within the data base found in Appendix
IX, the following results were obtained:
Total number of compounds: 22
Contingency table:

In Vivo Results

Corrositex
Results

Corrosive

Noncorrosive

Total

Corrosive

13

5

18

Noncorrosive

1

3

4

Total

14

8

22

Table 17. Comparison of Corrositex Results with In Vivo Results for Industrial
Chemical
Performance summary:Parameter
Equivalence =FormulaNumber of Compounds Correctly Identified

Results= 16/22 = 73%

Total Number of Compounds Tested
Sensitivity =Number of Corrosives Correctly Identified= 13/14 = 93%

Total Number of Corrosives
Specificity =Number of Noncorrosives Correctly Identified= 3/8 = 38%

Total Number of Noncorrosives
Predictive Value =(Corrosives)

Number of Corrosives Correctly Identified

Predictive Value =(Noncorrosives)

Number of Noncorrosives Correctly Identified

False Positive
Rate =
False Negative
Rate == 13/18 = 72%

Total Number of Corrosive Results= 3/4 = 75%

Total Number of Noncorrosive Results
Number of Noncorrosives Classified as Corrosive
Total Number of Noncorrosives Tested= 5/8 = 62%

Number of Corrosives Classified as Noncorrosive
Total Number of Corrosives Tested= 1/14 = 7%

Table 18. Summary of the Performance of the Corrositex Test Compared to In Vivo
Findings for Industrial Chemical.
C-15

Table18. Summaryof theSubmission
Performance
the Corrositex Test Compared to In Vivo®
Appendix
C: Corrositex
Test Method(May, of1998)
Findings for Industrial Chemical.
When surfactant was delineated within the data base found in Appendix IX, thefollowing results were obtained:
Total number of compounds: 14
Contingency table:

In Vivo Results

Corrositex
Results

Corrosive

Noncorrosive

Total

Corrosive000Noncorrosive

0

14

14

Total

0

14

14

Table 19. Comparison of Corrositex Results with In Vivo Results for Surfactant.
Performance summary:Parameter
Equivalence =FormulaNumber of Compounds Correctly Identified

Results= 14/14 = 100%

Total Number of Compounds Tested
Sensitivity =Number of Corrosives Correctly Identified= 0/0 = NA

Total Number of Corrosives
Specificity =Number of Noncorrosives Correctly Identified= 14/14 = 100%

Total Number of Noncorrosives
Predictive Value =(Corrosives)

Number of Corrosives Correctly Identified

Predictive Value =(Noncorrosives)

Number of Noncorrosives Correctly Identified= 0/0 = NA

Total Number of Corrosive Results= 14/14 = 100%

Total Number of Noncorrosive Results= 0/14 = 0%

Rate =

Number of Noncorrosives Classified as Corrosive
Total Number of Noncorrosives Tested

False Negative

Number of Corrosives Classified as Noncorrosive= 0/0 = NA

False Positive

Rate =

Total Number of Corrosives Tested

Table 20. Summary of the Performance of the Corrositex Test Compared to In Vivo
Findings for Surfactant.

C-16

Appendix C: Corrositex® Test Method Submission (May, 1998)

C-17

Appendix C: Corrositex® Test Method Submission (May, 1998)

V.C. Gordon, S. Mirhashemi, R. Wei and V. Harutunian, A New In Vitro Method
to Determine the Corrosivity Potential of Surfactants and Surfactant-Based
Formulations, Comunicaciones - Presentadas a la XXV Jornadas Del Comite
Espanol De La Detergencia.
P.A., Botham, et al., A Prevalidation Study on In Vitro Skin Corrosivity Testing:
The Report and Recommendations of ECVAM Workshop 6, ATLA 23, 219-255,
1995.
Copies of these manuscripts are included in Appendix XIII.

B. MISCELLANEOUS COMMENTS
1. Corrositex results should be compared with the in vivo classification of corrosive or
noncorrosive.
This has been done in the current response.

2. The chemicals that have been tested in a series of different concentrations need to beaddressed separately from chemicals tested only once.
Diluted samples of a chemical have not been included in the current data base(Appendix IV).

C. APPARENT INCONSISTENCIES AND DISCREPANCIES IN THE TABLES
THAT SHOULD BE CORRECTED OR EXPLAINED
1. Reproducibility within and between laboratories: Results for tests run on the samechemical or product in different labs to demonstrate interlaboratory reproducibility should
be combined into one table. Similarly, multiple tests of chemicals to demonstrate
intralaboratory repeatability or reproducibility should be combined into appropriate
tables.
The results of inter- and intra-laboratory reproducibility studies may be found on
pages 23 and 36 of Appendix I and pages 73 through 81 of Appendix II.

2. Performance of the test.
a. Calculate performance when scored as C vs. NC.
See Question 2 in Section A.

b. Calculate performance when scored as I, II, III, or NC.

Data found in Appendix IV has been analyzed to define the performance of the Corrositex testwhen scored as Packing Group I, II, III or NC. The following contingency table demonstrates
the performance of the Corrositex test when compared the in vivo data (Table 23). It should be
noted that samples whose in vivo data are listed as “C” or “R34” are not included in the analysis
C-18

Appendix C: Corrositex® Test Method Submission (May, 1998)

included in the analysis reported in Table 23. Sample #44 and 59 of Appendix IV

Reported in Table 23. Sample #44 and 59 of Appendix IV were not included either. Therefore
were not included, either. Therefore the total number of samples described in thisthe total number of samples described in this instance is 90.

instance is 90.

In Vivo Packing Group

Corrositex
Packing Group

I

II

III

NC

Total

I

3

1

1

0

5

II

1

28

1

7

37

III

0

0

1

8

9

Noncorrosive

1

0

0

38

39

Total

5

29

3

53

90

Table 23. Comparison of Packing Groups Defined by In Vivo Studies andthe Corrositex Test.

c. Performance of the test for different categories of substances.
See Question 7 & 13 in Section A.

d. Proportion of non-qualifying (NQ) substances among structure or use categories.
The submission in June 1996 contained 83 non-qualified samples. Current data basedoes not contain non-qualified samples.

3. Specific questions
a. Explain why there are two conflicting in vivo classifications for 95% caprylic acid.
The results of in vivo studies demonstrated that 95% caprylic acid was corrosive.
Briefly, the conflicting entries of corrosive and noncorrosive noted for this material
resulted from the following series of errors. Initially, when Table 39 on page 67 ofAppendix II was compiled, an incorrect designation of NC was entered in the in vivo
results columns of line 35. This erroneous entry was transcribed to line 240 of Table 49
found on page 90 and lines 368 and 369 of Table 54 found on pages 131 and 132 ofAppendix II. Please refer to pages 13-21 of the Supplement to Application for Revision
and Renewal of DOT E-10904 found in Appendix III for a detailed explanation andcorrection of this error.
C-19

Appendix C: Corrositex® Test Method Submission (May, 1998)

b. Explain why there are often 2-3 in vivo classifications listed for several chemicals.
These multiple classifications result from incomplete/insufficient in vivo studies
reported by the contract laboratory. While this laboratory was expected to employ invivo exposure periods of 4 hours, 1 hour, and 3 minutes respectively to determine
Packing Groups III, II or I; in some cases only the 4 hour and 1 hour exposure periods
were actually performed. In these instances when the 3 minute exposure period wasomitted, it was not possible to distinguish if the tested material should becharacterized as a packing group I or packing group II compound. Consequently, inthese cases, the in vivo classification “I, II” has been included in the listing found in
Table 49 of Appendix II.

c. Table 49, rows 952 and 953. The results for the two samples are virtually
identical, yet 952 is classified B1/II and 953 is classified B2/III. Provide an
explanation.
The samples are not duplicates with inconsistent results. The strippers should havebeen labeled Stripper A and Stripper B. These are individual formulations provided
by an industrial company.

d. Eliminate duplicate entries from Table 49.
Current data base does not contain duplicate entries.

e. Table 49: Describe what the entries under the column titled “In lab” mean; e.g., if
the space is blank or if there is an asterisk.
An asterisk entered under the column titled “In lab” indicates that the sample was
evaluated at InVitro International. A blank entry indicates that the sample was notevaluated at InVitro International. All the corrositex results of the current data basewere generated at InVitro International (Appendix VI).

f.

Table 54, lines 11 and 30. The same patterns of response are assigned different
concordances. This should be explained.

When Table 54 of Appendix II was originally formatted, lines 11 and 30 were asshown below:

C-20

Appendix C: Corrositex® Test Method Submission (May, 1998)#

Sample Name

Corrositex
Group

DOT

in vivo

Concordance

11

Hydrobromic

I

II

II

over

I

II

I

1

acid
30

Phosphorous
pentachloride

Thus the Corrositex test was judged to over-estimate the packing group ofhydrobromic acid (line 11) when compared to the in vivo test. By contrast, theresults of the packing group determination of Phosphorous pentachloride obtained
from the Corrositex test and the in vivo test were found to be concordant.
Prior to submission of the renewal application, Table 54 was re-formatted to clearlydelineate the compounds that were identified to be corrosive by the in vivo test. This
was achieved by replacing the in vivo packing group designations of I, II, or III withthe letter “C.” However, when this was done, the person responsible for compilingthe new version of the table failed to edit and amend the results reported in theconcordance column. Consequently the version of Table 54 found in Appendix II
contained the following lines:#

Sample Name

Corrositex
Group

DOT

in vivo

Concordance

11

Hydrobromic

I

II

C

over

I

II

C

1

acid
30

Phosphorous
pentachloride

Thus the apparent discrepancies identified by the reviewer resulting from editing
errors that occurred while the table was being compiled.
Every effort has been made to correct these types of errors in the data that isprovided with the current response.

g. Table 54. If Corrositex groups I, II, and III are all equivalent to a classification of“C,” why are some chemicals in Group I considered “over” (rows 10, 82, 83)
and others considered “under” (rows 116, 117, 149, 150, 160, 161) whencompared to the in vivo classification of “C?”

See Question 3f in Section C.
C-21

1 Boron Trifluoride-Dihydrate
2 Calcium Carbonate
3 Chromium (III) Fluoride
4 Copper (II) Chloride
5 Ferric Chloride
6 Glycol bromoacetate
7 Maleic Anhydride
8 Phosphorous Pentachloride
9 Phosphorous Tribromide
10 Potassium Bisulfate
11 Sodium bicarbonate
12 Sodium bisulphite
13 Sodium Hydrogen Fluoride
14 Sodium hypochlorite w/ 5% Chlorine
15 Boron trifluoride-acetic acid complex
16 HCl + Sulfuric acid + Citric acid
17 Sulfuric acid + Cellusolve
18 Sulfuric acid + Ferric Chloride
19 Sulfuric acid + SDS
20 Sulfuric acid + Triton X-100
21 Fluoboric Acid
22 Hydrobromic Acid
23 Hydrochloric acid
24 Phosphoric Acid
25 Sulfamic Acid
26 Sulfuric acid27 10-Undecenoic acid
28 2-Methylbutyric acid
29 3-3'-Dithiodipropionic acid
30 65/35 Octanoic/decanoic acids
31 70/30 Oleine/octanoic acid
32 Butyric Acid

# Sample Name

Acid Derivative
Acid Derivative
Acid Derivative
Acid Derivative
Acid Derivative
Acid Derivative
Acid Derivative
Acid Derivative
Acid Derivative
Acid Derivative
Acid Derivative
Acid Derivative
Acid Derivative
Acid Derivative
Acid Mixture
Acid Mixture
Acid Mixture
Acid Mixture
Acid Mixture
Acid Mixture
Acid, Inorganic
Acid, Inorganic
Acid, Inorganic
Acid, Inorganic
Acid, Inorganic
Acid, Inorganic
Acid, Organic
Acid, Organic
Acid, Organic
Acid, Organic
Acid, Organic
Acid, Organic

Product
CategoryConc.
Corrositex Resultsin vivo
wt% Time Category Packing
Group
96
1.53
1
I
I
Neat >2402
NCNC
97 171.6
2
NC
NC
99
35.71
1
II
NC
98 27.29
1
II
II
Neat NANA
R34
R34
99 35.65
1
II
III
98
0.08
1
I
I
97
1.02
1
I
I
Neat 25.11
1
II
I, II
Neat NA
NA
NC
NC
Neat NA
NA
NC
NC
99
71.57
2
NC
NC
5% Cl >240
2
NC
NC
98
3.47
1
II
II
5,5,5 9.09
1IIII
5,20 15.00
2
II
I, II
5, 2 14.98
2
II
I, II
5, 10 16.15
2
II
I, II
5, 10 16.86
2
II
I, II
48
2.49
1
I
III
48
2.28
1
I
II
14.4 NA
NA
R34
R34
85
10.96
1
II
II
99+ 22.63
1
II
NC
10
NA
NA
R34
C
NA
NA
NA
NC
NC
NA
NA
NA
R34
R34
NA
NA
NA
NC
NC
65/35 NA
NA
NC
R34
70/30 NANA
NC
NC
99 40.57
1
II
II
Corrositex
data
sourcep1p31, #7
p13
p58, 59
p16
ECVAM
p17
p18
p2 & 18
p49, #2
ECVAM
ECVAM
p18
p48, #4
p56, #2
p72
p71
p71
p71
p71
p1 & 16
p2
ECVAM
p17
p19
ECVAM
ECVAM
ECVAM
ECVAM
ECVAM
ECVAM
p2 &14

Categorydatasource
p87
p75
p88
p99
p88
ECVAM
p87
p89
p88
p94
ECVAM
ECVAM
p89 & 91
p75
p86
p92
p93
p93
p93
p93
p88
p85
ECVAM
p88
p89
ECVAM
ECVAM
ECVAM
ECVAM
ECVAM
ECVAM
p88

in vivodata
source1-3-70841, #1
1-3-78700, #23
1-3-70841, #3
1-3-70841, #12
1-3-70841, #16
ECVAM
1-3-70841, #18
1-3-70841, #6
1-3-70841, #7
1-3-82069, #45
ECVAM
ECVAM
1-3-70841, #8
1-3-82588-3, #20
1-3-70841, #2
1-3-82069, #28
1-3-82069, #55
1-3-82069, #56
1-3-82069, #57
1-3-82069, #58
1-3-70841, #4
1-3-70841, #5
ECVAM
1-3-70841, #19
1-3-70841, #22
ECVAM
ECVAM
ECVAM
ECVAM
ECVAM
ECVAM
1-3-70841, #11

Appendix C: Corrositex® Test Method Submission (May, 1998)

C-22

33 Hexanoic Acid
34 Maleic Acid
35 Octanoic acid
36 Propionic Acid
37 Cinnamaldehyde
38 1-(2-Aminoethyl) piperazine
39 2,4-Xylidine (2,4-Dimethylaniline)
40 Butylamine (in EtOH/EG 1:1)
41 Cyclohexylamine
42 Diaminopropane, 1,2­
43 Dicyclohexylamine
44 Dimethyldipropylenetriamine
45 Dimethylisopropylamine
46 Dimthylbenzylamine, N,N47 Ethanolamine
48 Hydrogenated tallow amine
49 n-Heptylamine
50 Tallow amine
51 Tributylamine
52 NaOH/BAC (1:10)
53 NaOH/SDS (1/10)
54 NaOH/SMS (1/10)
55 NaOH/SMS (5/3)
56 NaOH/TX100
57 2-Mercaptoethanol, Na salt
58 Potassium hydroxide
59 Sodium carbonate
60 APL 9372
61 Boat Bottom Cleaner
62 COR 11
63 COR 18
64 COR 19# Sample NameAcid, Organic
Acid, Organic
Acid, Organic
Acid, Organic
Aldehyde
Amine
Amine
Amine
Amine
Amine
Amine
Amine
Amine
Amine
Amine
Amine
Amine
Amine
Amine
Base Mixture
Base Mixture
Base Mixture
Base Mixture
Base Mixture
Base, Inorganic
Base, Inorganic
Base, Inorganic
Cleaner
Cleaner
Cleaner
Cleaner
Cleaner

Product
CategoryConc.
Corrositex Resultsin vivo
wt% Time Category Packing
Group
Neat 133.4
1
III
C
99
9.56
1
II
NC
NA
NA
NA
NC
R34
99+ 19.19
1
IIII
Neat NANA
NC
NC
99 38.78
1
II
II
NA
NA
NA
NC
NC
81.8 26.33
1
III
C
Neat 42.79
1
IIC
99+ 21.67
1III
97 190.87
1
III
C
NA
NA
NA
R34
R35
NA
NA
NA
R34
R34
99+ 86.17
1
IIIIII
99+ 23.88
1
II
II
NA
NA
NA
NC
NC
NA
NA
NA
R34
R34
NA
NA
NA
NC
R35
99+ >2402NCNC
1,10 34.33
2
IIIC
1,10 32.1
2
IIIC
1,10 17.66
2
IIII
5,3 15.59
1
IIC
5,5 15.23
2
II
I, II
45
NA
NA
R34
R34
10
NA
NA
R34
C
50
NA
NA
R34
NC
Neat 16.61
2
IINC
Neat 23.78
2
II
I, II
Neat 31.75
2
III
C
Neat 30.78
2
III
NC
Neat 23.92
NF
II
I, II
Corrositex
data
sourcep13 & 20
p17
ECVAM
p18, 19
ECVAM
p18
ECVAM
p61, #3
p84
p1
p52
ECVAM
ECVAM
p1
p35
ECVAM
ECVAM
ECVAM
p13
p22, #2
p23, #1
p28, #10
p32
p32
ECVAM
ECVAM
ECVAM
p28, #2
p49, lastp4
p60, lastp4

Categorydatasource
p92
p88
ECVAM
p89
ECVAM
p11, #3
ECVAM
p80
p57, last
p11, #6
p11, #10
ECVAM
ECVAM
p82
p11, #14
ECVAM
ECVAM
ECVAM
p75
p74
p74
p74
p83
p83
ECVAM
ECVAM
ECVAM
p78
p93
p7
p8
NF

in vivodata
source1-3-82069, #31
1-3-70841, #17
ECVAM
1-3-70841, #20
ECVAM
1-3-70841, #9
ECVAM
1-3-80626-3, #60
1-3-82069, #19
1-3-70841, #13
1-3-82069, #20
ECVAM
ECVAM
1-3-82069, #21
1-3-70841, #15
ECVAM
ECVAM
ECVAM
1-3-82588-3, #21
1-3-82069, #34
1-3-82069, #35
1-3-82069, #42
1-3-78830, #34
1-3-82069, #43
ECVAM
ECVAM
ECVAM
1-3-80626-2, #49
1-3-82069, #32
1-3-82069, #51
1-3-82069, #46
1-3-78540, #10

Appendix C: Corrositex® Test Method Submission (May, 1998)

C-23

65 COR 20
66 COR 4
67 COR 6
68 COR 9
69 COR370 Coverage Plus
71 Larc Super
72 Toilet Duck Green73 ZFA
74 ZWS 9352
75 Windex Blue
76 Cascade
77 Tide78 Trichlorotoluene
79 31580 48581 88082 3000
83 4000
84 122 B
85 1702 BR
86 1703 CR
87 1709 B
88 3-11-23x Undyed
89 3-12-02P
90 3-12-03K Undyed
91 BSS 9487
92 Formula # 100-016
93 Formula # 100-057B
94 Formula # 100-088
95 GIN
96 LMCRK
97 Solcenic 2BW# Sample NameConc.
Corrositex Resultsin vivo
wt% Time Category Packing
Group
Cleaner
Neat 30.17
2
III
C
Cleaner
Neat 39.00
2
III
NC
Cleaner
Neat 17.91
2
IINC
Cleaner
Neat 35.3
2
III
C
Cleaner
Neat 15.17
1
II
I, II
Cleaner
Neat 88.9
2
NCC
Cleaner
Neat >240
NF
NC
NC
Cleaner
Neat 153.5
2
NCNC
Cleaner
Neat 72.91
2
NC
NC
Cleaner
Neat 31.48
2
III
C
Cleaner, glass
Neat 34.78
2
III
NC
Detergent, dishwashing Neat 60.95
1
IIINC
Detergent, Laundry
Neat 69.96
1
III
NC
Halogenated Aromatic Hy 99
>240
2
NC
NC
Industrial Chemical
Neat 28.61
NF
II
I, II
Industrial Chemical
Neat 28.25
NF
II
I, II
Industrial Chemical
Neat 15.86
NF
II
I, II
Industrial Chemical
Neat 24.17
NF
II
I, II
Industrial Chemical
Neat 20.34
NF
II
I, II
Industrial Chemical
Neat 12.44
NF
II
I, II
Industrial Chemical
Neat 26.13
NF
II
I, II
Industrial Chemical
Neat 28.43
NF
II
I, II
Industrial Chemical
Neat 27.11
NF
II
I, II
Industrial Chemical
Neat 45.03
2
III
NC
Industrial Chemical
Neat 47.79
2
III
NC
II
NC
Industrial Chemical
Neat 25.5
NF
Industrial Chemical
Neat 13.98
1
IIC
Industrial Chemical
Neat 41.67
2
IIIC
Industrial Chemical
Neat >240
2
NC
C
Industrial Chemical
Neat 40.29
2
III
C
Industrial Chemical
Neat 11.19
2
IINC
Industrial Chemical
Neat 22.1
2
II
I, II
Industrial Chemical
Neat 69.62
2
NCNC
Product
Category

Corrositex
data
source
p5
p3
p4
p4
p67
p33
p69, 70
p53, #5
p34, #8
p28, #11
p54, #3
p33, 73
p35
p14
p46 #3
p39, #1
p46, #2
p41, #1
p40, #2
p47, #4
P41, #4
p41, #2
p41, #3
p27, #9
p34, #4
p30, #1
p29, #12
p98, #3
p102
p 24,
p34, #3
p26, #1
p105

Categorydatasource
p8
p10
p8
p8
p8
p77
NF
p75
p79
p78
p75
p81
p76
p90
NF
NF
NF
NF
NF
NF
NF
NF
NF
p79
p79
NF
p78
p9
p103
p10, # 16
p92
p77
p9

in vivodata
source1-3-82069, #47
1-3-80626-2, #32
1-3-78700, #19
1-3-82069, #50
1-3-78540, #7
1-3-78700, #16
1-3-80626-3, #64
1-3-78540, #11
1-3-80626-2, #45
1-3-86156-1, #1
1-3-78540, #12
1-3-78700, #14
1-3-78700, #13
1-3-82588-3, #19
1-3-84605-2, #9
1-3-84605-2, #12
1-3-84605-2, #5
1-3-84605-2, #10
1-3-84605-2, #11
1-3-84605-2, #4
1-3-84605-2, #6
1-3-84605-2, #8
1-3-84605-2, #7
1-3-80626-3, #62
1-3-80626-3, #61
1-3-80626-3, #63
1-3-80626-2, #46
1-3-86156-4, #4
1-3-86156-5, #7
1-3-86156-4, #5
1-3-80626-2, #44
1-3-82069, #13
1-3-80749, #4

Appendix C: Corrositex® Test Method Submission (May, 1998)

C-24

98 Solcenic 3A
99 Solcenic 3B
100 T B Q
101 91440
102 20/80 Coconut/palm soap
103 RP-26
104 RP-29
105 RP-33
106 RP-34
107 RP-39
108 RP-40
109 RP-46
110 RP-49
111 RP-52
112 RP-53
113 RP-57
114 RP-61
115 RP-80B
116 RP-81B
117 Sodium undecylenate
118 Cellusolve + TX-100
NA: Not available
NF: Not found# Sample Name

Industrial Chemical
Industrial Chemical
Industrial Chemical
Petrochemical
Surfactant
Surfactant
Surfactant
Surfactant
Surfactant
Surfactant
Surfactant
Surfactant
Surfactant
Surfactant
Surfactant
Surfactant
Surfactant
Surfactant
Surfactant
Surfactant
Surfactant Blend

Product
Category
Neat 138.79
Neat 70.13
Neat 56.25
Neat >240
Neat
NA
Neat >240
Neat >240
Neat >240
Neat >240
Neat >240
Neat >240
Neat >240
Neat 99.08
Neat >240
Neat >240
Neat >240
Neat >240
Neat >240
Neat >24033
NA
20/10 >240

2
2
2
2
NA
2
2
2
2
2
2
2
2
2
2
2
2
2
2
NA
2

NC
NC
III
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC

NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC

Conc.
Corrositex Resultsin vivo
wt% Time Category Packing
Group
p73
p104
p22, #8
p65
ECVAM
p62
p62
p64
p62
p62
p62
p63
p55, #1
p63
p63
p63
p63
p66
p66
ECVAM
p50, #14

Corrositex
data
source
p9
p9
p77
p100
ECVAM
p95
p95
p95
p97
p97
p95
p97
p95
p95
p95
p95
p95
p96
p97
ECVAM
p93

Categorydatasource1-3-80749, #6
1-3-80749, #5
1-3-78700, #15
1-3-73960, #17
ECVAM
1-3-76818, #14
RP data
RP data
RP data
RP data
1-3-76818, #16
RP data
RP data
RP data
RP data
RP data
RP data
1-3-76818, #17
1-3-76818, #18
ECVAM
1-3-82069, #7

in vivodata
sourceAppendix C: Corrositex® Test Method Submission (May, 1998)

C-25

C-26

Appendix D(December, 1995)

D-1

Appendix D: Corrositex® Instruction Manual

D-2

Appendix D: Corrositex® Instruction Manual

D-3

Appendix D: Corrositex® Instruction Manual

D-4

Appendix D: Corrositex® Instruction Manual

D-5

Appendix D: Corrositex® Instruction Manual

D-6

Appendix D: Corrositex® Instruction Manual

D-7

Appendix D: Corrositex® Instruction Manual

D-8

Appendix D: Corrositex® Instruction Manual

D-9

Appendix D: Corrositex® Instruction Manual

The following information is provided as an example of how the Corrositex® assay
is performed. Color copies of the “How-To Guide” may be obtained by contacting
InVitro International, Inc. at 1-800-2-INVITRO.

D-10

Appendix D: Corrositex® Instruction Manual

D-11

Appendix D: Corrositex® Instruction Manual

D-12

Appendix D: Corrositex® Instruction Manual

D-13

Appendix D: Corrositex® Instruction Manual

D-14

Appendix D: Corrositex® Instruction Manual

D-15

Appendix D: Corrositex® Instruction Manual

D-16

Appendix D: Corrositex® Instruction Manual

D-17

Appendix E

NICEATM1 Comparison of the Corrositex® Instruction Manuals
All data submitted in the 1998 Corrositex® Submission was performed according to theCorrositex® Instruction Manual (revised 1/95).
The current Corrositex® Instruction Manual(Appendix D) was revised on 12/95. The procedures listed in the two manuals are similar,
except for slight modifications including:1.

Biomembrane preparations are to be prepared in the same manner; however, the 12/
95 revised manual states that biobarriers
are stable for 7 days as compared to 10 daysin the 1/95 manual.

2.

“Prequalification Test” and “Screening”
procedures in the 1/95 manual are similar
to the “Qualify” and “Categorize” proce­dures listed in the 12/95 manual. The
stepwise assay procedures are similar be­
tween the two manuals, as are the calcula­tions for the Corrositex® breakthroughtime. Positive and negative controls andtheir associated breakthrough times arelisted only in the 12/95 revised manual. For
determination of Packing Group, US Department of Transportation (US DOT) Ap­
proved Category A/B in the 1/95 manualis labeled “Category I”, in the revised 12/
95 Instruction Manual; the same break­through Corrositex® times (minutes) areused for both manuals. US DOT Pending
Category A/B in the 1/95 manual is labeled“Category 2” in the revised 12/95 submis­
sion. At the request of the US DOT, theCorrositex® times (minutes) for Category
2 agents for Packing Group III designation
has changed from “>30 to 45 minutes” inthe 1/95 manual to “>30 to 60 minutes” inthe 12/95 manual. Similarly, theCorrositex® times (minutes) for Category
2 agents for noncorrosive designation haschanged from “>45 minutes” in the 1/95
manual to “>60 minutes” in the 12/95
manual.

1

NICEATM = National Toxicology Program (NTP) Interagency Center for the Evaluation of Alternative Toxicologi­
cal Methods

E-1

E-2

Appendix F

NICEATM1 List of Nonqualifying Chemicals for Corrositex®
The following table lists chemicals that were
nonqualifying for Corrositex®. The chemicals
were obtained from the following sources as
indicated in the reference column of the table:

1998. The ECVAM international validation
study on in vitro tests for skin corrosivity.
2. Results and evaluation by the manage­
ment team. Toxicol. In Vitro 12:483-524.

• Barratt, M. D., P. G. Brantom, J. H. Fentem,• Gordon, V. C., J. D. Harvell, and H. I.

I. Gerner, A. P. Walker, and A. P. Worth.
1998. The ECVAM international validation
study for in vitro tests for skin corrosivity.
1. Selection and distribution of the test
chemicals. Toxicol. In Vitro 12:471-482.

Maibach. 1994. Dermal corrosion, theCorrositex system: A DOT accepted method
to predict corrosivity potential of test mate­rials. Alternative Methods Toxicol. 10:37­
45.

• Botham, P. A., M. Chamberlain, M. D.

• InVitro International, Inc. Corrositex®

Barratt, R. D. Curren, D. J. Esdaile, J. R.
Gardner, V. C. Gordon, B. Hildebrand, R.
W. Lewis, M. Liebsch, P. Logemann, R.
Osborne, M. Ponec, J.-F. Régnier, W.
Steiling, A. P. Walker, and M. Balls. 1995.
A prevalidation study on in vitro skincorrosivity testing: The report and recom­
mendations of ECVAM Workshop 6. ATLA
23:219-255.

ICCVAM Submission, May, 1998•

Appendix XIII of the October 11, 1996 sub­mission. Please note that data sheets were
not provided for this submission. However,to expand the data base of nonqualifiers,
these data were provided for consideration
the Peer Review Panel (PRP).

• Fentem, J. H., G. E. B. Archer, M. Balls, P.
A. Botham, R. D. Curren, L. K. Earl, D. J.
Esdaile, H.-G. Holzhütter, and M. Liebsch.

1

NICEATM = National Toxicology Program (NTP) Interagency Center for the Evaluation of Alternative
Toxicological Methods

F-1

F-2
+
NP
NP

Arquad DMMCB-50

benzophenone

benzyl alcohol

3.9

6.38

7.82

7.82

NP

NP

NP

NP

7.18

8.16

6.65

5.5

NP

NP

NP

5.7

4.6

6.6

pH

Barratt et al. (1998);
Fentem et al. (1998)

1996 Submission

1996 Submission

1996 Submission

Botham et al. (1995)

1996 Submission

1996 Submission;
Botham et al. (1995)

1996 Submission

1996 Submission

1996 Submission

1996 Submission

Barratt et al. (1998);
Fentem et al. (1998)

1996 Submission

1996 Submission

1996 Submission

1996 Submission

1996 Submission

1996 Submission

References

Abbreviations: C=corrosive; NC=noncorrosive; NP=not provided; SAR=structure activity relationship-+arquad 16-50

2-bromobutane; butyl bromide+

Arquad 16-50--

anionic blend 4

betaine--ammonium lauryl sulfate

anionic/ amphoteric blend 1-

4-amino-1,2,4-triazole--

alkylphosphoric acid 4M

amphoteric/ anionic / nonionic 2 surfactant blend-

alkyl (4EO) phosphoric acidNP

agrochemical N-NP

agrochemical I

alkyl benzene sulfonate

NP

In Vivo

agrochemical C

Chemical Name

Comment

Appendix F: NICEATM List of Nonqualifying Chemicals

F-3
+
+
-

disodium cocoamphodipropionate

dodecanoic acid (lauric acid)

Dowanol PNB

DuoquadDuoquad T-50

Elfan OS46

NP

NP

NP

NP

NP

NP

NP

5.57

NP

NP

NP

6.82

NP

3.9

2.97

3.6

7.59

pH

Botham et al. (1995)

1996 Submission

1996 Submission;
Botham et al. (1995)

Botham et al. (1995)

Barratt et al. (1998);
Fentem et al. (1998)

1996 Submission

1996 Submission

1996 Submission

1996 Submission

1996 Submission

1996 Submission

1996 Submission

1996 Submission

Barratt et al. (1998);
Fentem et al. (1998)

1996 Submission

Barratt et al. (1998);
Fentem et al. (1998)

1996 Submission

References

Abbreviations: C=corrosive; NC=noncorrosive; NP=not provided; SAR=structure activity relationship-disodium cocoamphodiacetate-

clyceryl stearate glyceryl--

chloroform

disodium sulfosuccinate-

catearyl alcohol++

carvacrol

dicocoalkylbenzyl-ammoniumchloride+

caprylic acid+-n -butyl propionate

cocoalkyl benzyl ammonium chloride-

In Vivobutylbenzene

Chemical Name

Borderline C/NC chemical, as judged
subjectively from the proximity of thechemical to the classification boundary(SAR analysis).

Comment

Appendix F: NICEATM List of Nonqualifying Chemicals

-

foralkyl AC8N

F-4
-

-

-

methacrylate d'allyeo-m-e thoxyphenol Guaiacol

p -methylthiobenzaldehyde

4,4-methylenebis(2,6-di-tert- butylphenol)

methyl laurate

methyl palmitate

4-(methylthio)benzaldehyde

6.8

NP

3.9

NP

NP

3.9

NP

NP

3.6

3.6

NP

NP

NP

6.74

NP

NP

3.9

pH

Barratt et al. (1998);
Fentem et al. (1998)
Barratt et al. (1998);
Fentem et al. (1998)
Barratt et al. (1998);
Fentem et al. (1998)
Barratt et al. (1998);
Fentem et al. (1998)

1996 Submission

Barratt et al. (1998);
Fentem et al. (1998)

1996 Submission

Barratt et al. (1998);
Fentem et al. (1998)
Barratt et al. (1998);
Fentem et al. (1998)
1996 Submission;
Botham et al. (1995)

1996 Submission

Botham et al. (1995)

1996 Submission;
Botham et al. (1995)

1996 Submission

1996 Submission

1996 Submission

Barratt et al. (1998);
Fentem et al. (1998)

References

Abbreviations: C=corrosive; NC=noncorrosive; NP=not provided; SAR=structure activity relationship--isopropanollauric acid-hydrogen peroxide--

Hostaphat KLD

isostearic acid-n -hexanol

NP-

EXP 3830 D

glycine-

In Vivo2-ethoxyethyl methacrylate

Chemical Name

Borderline C/NC chemical as judged
subjectively from the proximity of thechemical to the classification boundary(SAR analysis).

Comment

Appendix F: NICEATM List of Nonqualifying Chemicals

F-5

NP
NP
NP
NP
NP
NP
NP
NP
+

petrochemical 26A

petrochemical 40A

petrochemical 48A

petrochemical 49A

petrochemical 5

petrochemical 58A

petrochemical 59A

petrochemical 69A

phenethyl bromide

2-phenylethanol

Proxel BD

NP

3.6

3.6

8.59

7.4

7.2

7.86

9.05

8.54

7.54

7.54

6.2

8.57

3.69

NP

8.97

0.43

NP

3.9

pH

Botham et al. (1995)

Barratt et al. (1998);
Fentem et al. (1998)
Barratt et al. (1998);
Fentem et al. (1998)

1996 Submission

1996 Submission

1996 Submission

1996 Submission

1996 Submission

1996 Submission

1996 Submission

1996 Submission

1996 Submission

1996 Submission

1996 Submission

1996 Submission

1996 Submission;
Botham et al. (1995)

1996 Submission

1996 Submission

Barratt et al. (1998);
Fentem et al. (1998)

References

Abbreviations: C=corrosive; NC=noncorrosive; NP=not provided; SAR=structure activity relationshipNPpetrochemical 22-

Noramium M2SH3

NP-

n -nonanol

petrochemical 1A-

myristyl myristateNP-

mixed C8 amphocarboxylic acidpetrochemical 12-

In Vivomenthyl trimethylacetate; methyl pivalate

Chemical Name

Comment

Appendix F: NICEATM List of Nonqualifying Chemicals

F-6
+

-

2-tert- butylphenol

thioglycolate d'isooctylen -undecanol

1-undecanol

6.8

6.8

NP

3.9

5.69

NP

NP

7.89

NP

NP

3.9

NP

NP

NP

7.14

5.12

8.99

NP

pH

1996 Submission

1996 Submission;
Botham et al. (1995)

1996 Submission

Barratt et al. (1998);
Fentem et al. (1998)

1996 Submission

1996 Submission

1996 Submission

1996 Submission

1996 Submission

1996 Submission

Barratt et al. (1998);
Fentem et al. (1998)

1996 Submission

1996 Submission

1996 Submission

1996 Submission

1996 Submission

1996 Submission

1996 Submission

References

Abbreviations: C=corrosive; NC=noncorrosive; NP=not provided; SAR=structure activity relationship-sulfoccinate-

sodium methyl cocoyl taurate--

sodium lauryl sulfate (20% aq.); SDS; SLS; sodium
dodecyl sulfate; Irium

stearyl stearate-

sodium lauroamphoacetate/trideceth sulfate--

sodium cocoamphoproprionate

stearyl alcohol, cetrimonium bromide-

sodium cocoamphohydroxypropylsulfonate--

sodium caproamphoacetate

sodium trideth sulfate-

sodium butoxyethoxy acetate--

sodium benzyl sulfonate

sodium stearoamphoacetate-

In Vivosodium laureth carboxylate-13

Chemical Name

Borderline C/NC chemical as judged
subjectively from the proximity of thechemical to the classification boundary(SAR analysis).

Comment

Appendix F: NICEATM List of Nonqualifying Chemicals

Appendix G

NICEATM1 Evaluation of Nonqualifying Chemicals
Data Set Including the 1996 InVitro International, Inc. (IVI) Submission
The list of nonqualifying chemicals provided in Appendix F was expanded to include data from the1996 IVI submission. A breakdown of the data sources for nonqualifying chemicals is provided in
the table below. Of the 75 chemicals for which in vivo data was provided, 64 chemicals (85%) wereclassified as noncorrosive in the in vivo test. The remaining 11 chemicals (15%) were classified as
corrosive according to the in vivo test.
pH data were provided for 50 chemicals, and the overall distribution is shown in the attached
Figure 1. All but one of the nonqualifying chemicals were in the pH range of 3 to 10; for thisanalysis, all pH values were rounded to the nearest whole number.
Both in vivo and pH data were provided for 33 chemicals, and the pH distribution for these materi­als is shown in Figure 2. Of these 33 chemicals, one would be classified as corrosive using the pH
test, although in vivo data indicates that this chemical is noncorrosive; 3 chemicals in the pH range
between 3 and 3.9 would be classified as corrosive according to in vivo results.
Data Set Excluding the 1996 IVI Submission
Data on 30 nonqualifying chemicals were provided in the Fentem et al. (1998) and Botham et al.
(1995) papers. Of these 30 materials, 24 (80%) were classified as noncorrosive in the in vivo test.
The remaining 6 (20%) were classified as corrosive according to the in vivo test. Both pH and invivo data were available for 18 chemicals in this data set; the pH distribution for these chemicals
was nearly identical to that found for the 33 chemicals in the total data set.
Source of Data on Nonqualifying Test Materials
SourceNQ (Total)

With pHdata

Without
pH dataWith invivo data

Without
in vivodata

With pHand in vivo
data

Fentem et al. (1998)
Botham et al. (1995)
Gordon et al. (1994)
1998 IVI submission
1996 IVI submissionb

18
12
0
0a
62

15
3
-­
-­
32

3
9
-­
-­
30

18
12
-­
-­
45

-­
-­
-­
-­
17

15
3
-­
-­
15

Total

92

50

42

75

17

33

a

IVI was advised by the Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM) not
to submit data for nonqualifying chemicals.
bNote that data sheets were not submitted for these results; therefore, no quality assurance audit was conducted forthese data.
1

NICEATM = National Toxicology Program (NTP) Interagency Center for the Evaluation of Alternative Toxicologi­
cal Methods

G-1Number of Chemicals

Number of Chemcials

G-2

0

2

4

6

8

10

12

14

16

0

1

1

2

3

15

4

1

5

5

6

10

pH

7

11

8

4

9

3

10

Figure 1. pH Distribution for Nonqualifying Chemicals (Total) (N=50)

11

12

13

14

Appendix G: NICEATM Evaluation of Nonqualifying Chemicals

Number of Chemcials

G-3

0

2

4

6

8

10

12

14

16

0

1

1

2

3

11

3

4

5

4

6

7

7

4

8

1
9

2

10

11

12

13

14

Figure 2. pH Distribution for Nonqualifying Chemicals for which In Vivo Data was
Available (N=33)
Figure 2. pH Distribution for Nonqualifying Chemicals for which In Vivo Data was Available (N=33)

Corrosive
12345
12345
12345
12345
12345
12345

Noncorrosive

Appendix G: NICEATM Evaluation of Nonqualifying Chemicals

G-4

H-1

1

24.17

20.25

3000

4000

140-31-8

112-38-9

1-(2-aminoethyl)piperazine

10-Undecenoic acid

38.83

38.73

21.67

20.50

24.08

16.37

28.50

20.53

24.48

15.65

28.33

28.63

20.03

24.80

16.17

28.17

28.57

20.37

23.90

15.37

28.00

28.47

20.33

23.58

15.25

27.83

28.37

38.78

21.67

20.34

24.17

15.86

28.25

28.61

Mean

0.07

0.00

0.18

0.43

0.50

0.31

0.19

Standard
Deviation

NICEATM = National Toxicology Program (NTP) Interagency Center for the Evaluation of Alternative Toxicological Methods

78-90-0

1,2-diaminopropane

21.67

16.33

880

91440

28.67

485

28.75

Time 1 Time 2 Time 3 Time 4 Time 5 Time 6

28.88

CASRN

315

Chemical Name

Source: ECVAM Validation Study(Fentem et al., 1998). No
original data submitted.

Not found in provided data sheets.

Comments

NICEATM Table of Breakthrough Times for Chemicals Provided by InVitro International, Inc.

Appendix H

H-2

27.23

27.92

24.93

26.73

28.42

27.92

12.73

27.11

28.43

26.13

12.44

0.27

0.28

1.46

0.21

Source: ECVAM Validation Study(Fentem et al., 1998). No
original data submitted.

Source: ECVAM Validation Study(Fentem et al., 1998). No
original data submitted.

Source: ECVAM Validation Study(Fentem et al., 1998). No
original data submitted.

1119-62-6

Source: ECVAM Validation Study(Fentem et al., 1998). No
original data submitted.

26.93

28.33

25.13

12.53

Comments

3,3'-Dithiodipropionic acid

27.17

28.58

28.12

12.28

Standard
Deviation

Source: ECVAM Validation Study(Fentem et al., 1998). No
original data submitted.

600-07-7

27.53

28.63

25.20

12.22

Mean

20/80-coconut/palm soap

2-methylbutyric acid

2-mercapoethanol, sodium
salt (45% aq.)37482-11-4

27.08

1709B

95-68-1

28.67

1703CR

2,4-xylidine

25.70

1702BR

12.25

Time 1 Time 2 Time 3 Time 4 Time 5 Time 6

12.60

CASRN

122B

Chemical Name

Appendix H: NICEATM Table of Breakthrough Times

H-3
>4h

171.67

Cellosolve + TX100

chromium(III) fluoride

35.68

31.83

copper(II) chloride

COR 11cinnamaldehyde

62.52

>4h

Cascade14371-10-9

107-92-6

butyric acidcalcium carbonate

25.58

109-73-9
64-17-5
107-21-1butylamine (in ethanol[EtOH]/ethylene glycol [EG]
1:1)
40.58

13.98

BSS 9487

31.67

35.85

171.52

61.37

40.55

27.07

13.98

3.40

35.60

3.43

Time 1 Time 2 Time 3 Time 4 Time 5 Time 6

3.57

CASRN

boron trifluoride-acetic acidcomplex

Chemical Name

31.75

35.71

171.60

60.95

40.57

26.33

13.98

3.47

Mean

0.11

0.13

0.11

0.81

0.02

1.05

0.00

0.09

Standard
Deviation

Source: ECVAM Validation Study(Fentem et al., 1998). No
original data submitted.

Comments

Appendix H: NICEATM Table of Breakthrough Times

H-4
>4h

171.67

Cellosolve + TX100

chromium(III) fluoride

35.68

31.83

copper(II) chloride

COR 11cinnamaldehyde

62.52

>4h

40.58

25.58

Cascade14371-10-9

107-92-6

butyric acidcalcium carbonate

109-73-9
64-17-5
107-21-1butylamine (in EtOH/EG 1:1)

13.98

BSS 9487

31.67

35.85

171.52

61.37

40.55

27.07

13.98

3.40

35.60

3.43

Time 1 Time 2 Time 3 Time 4 Time 5 Time 6

3.57

CASRN

boron trifluoride-acetic acidcomplex

Chemical Name

31.75

35.71

171.60

60.95

40.57

26.33

13.98

3.47

Mean

0.11

0.13

0.11

0.81

0.02

1.05

0.00

0.09

Standard
Deviation

Source: ECVAM Validation Study(Fentem et al., 1998). No
original data submitted.

Comments

Appendix H: NICEATM Table of Breakthrough Times

H-5

30.17

15.17

39.08

17.92

35.42

88.17

42.82

108-91-8

101-83-7

COR 20

COR 3

COR 4

COR 6

COR 9

Coverage Plus

cyclohexylamine

dicyclohexylamine

182.4823.83

COR 19196.30

42.75

88.00

35.33

17.90

38.92

15.17

30.17

24.00

31.98

187.88196.82Time 1 Time 2 Time 3 Time 4 Time 5 Time 6

29.58

CASRN

COR 18Chemical Name

190.87

42.79

88.90

35.30

17.91

39.00

15.17

30.17

23.92

30.78

Mean

6.93

0.05

0.12

0.06

0.01

0.11

0.00

0.00

0.12

1.70

Standard
Deviation
Comments

Appendix H: NICEATM Table of Breakthrough Times

H-6
>4h

40.50

11.20

Formula # 100-057B

Formula # 100-088

GIN

2.43

41.83

16872-11-0

fluoboric acid; hydrogentetrafluoroborate

27.33

22.03

Formula # 100-016

7705-08-0

ferric chloride; iron (III)chlorideethanolamine 80%

23.92

11.18

40.37

41.67

2.55

27.25

22.15

23.83

40.3

41.50

40.25

40.13

40.17

11.19

40.29

41.67

2.49

27.29

22.09

23.88

0.01

0.14

0.17

0.08

0.06

0.08

0.06

141-43-5

ethanolamine

Comments

Source: ECVAM Validation Study(Fentem et al., 1998). No
original data submitted.

Standard
Deviation

996-35-0

Mean

dimethylisopropylamine

Time 1 Time 2 Time 3 Time 4 Time 5 Time 6

Source: ECVAM Validation Study(Fentem et al., 1998). No
original data submitted.

CASRN

dimethyldipropylenetriamine 10563-29-8

Chemical Name

Appendix H: NICEATM Table of Breakthrough Times142-62-1

7647-01-1

hexanoic acidhydrochloric acid (14.4% wt)

H-7
>4h

21.97

9.58

LMCRK

maleic acid61788-45-2hydrogenated tallow amine

2.53

9.07

133.43

9.53

22.23

2.03

9.10

133.37

Time 1 Time 2 Time 3 Time 4 Time 5 Time 6

Larc Super

10035-10-6hydrogen bromide, aqueous
sol.; hydrobromic acidhydrochloric acid + sulfuric
acid + citric acid3785-34-0

CASRN

glycol bromoacetate (85%)

Chemical Name

9.56

22.10

2.28

9.09

133.40

Mean

0.04

0.18

0.35

0.02

0.04

Standard
Deviation

Source: ECVAM Validation Study(Fentem et al., 1998). No
original data submitted.

Source: ECVAM Validation Study(Fentem et al., 1998). No
original data submitted.

Source: ECVAM Validation Study(Fentem et al., 1998). No
original data submitted.

Comments

Appendix H: NICEATM Table of Breakthrough Times

10026-13-8

7789-60-8

7646-93-7

1310-58-3

1310-58-3

phosphorus pentachloride

H-8

phosphorus tribromide

potassium bisulfate;
potassium hydrogen sulfate

potassium hydroxide (5% aq.)potassium hydroxide 3%

21.08

21.78

1.00

0.08

10.95

124-07-02

octanoic acid; caprylic acid7664-38-2

111-68-2

n- Heptylamine

phosphoric acid86.17

103-83-3

N,N -dimethylbenzylamine

21.20

28.13

1.03

0.08

10.97

86.17

81.42

81.7

Time 1 Time 2 Time 3 Time 4 Time 5 Time 6

81.47

CASRN

Master Chemical 019A

Chemical Name

21.14

24.96

1.02

0.08

10.96

86.17

81.53

Mean

0.08

4.49

0.02

0.00

0.01

0.00

0.15

Standard
Deviation

Source: ECVAM Validation Study(Fentem et al., 1998). No
original data submitted.

Mean is listed as 25.11 in the
Submission.

Source: ECVAM Validation Study(Fentem et al., 1998). No
original data submitted.

Source: ECVAM Validation Study(Fentem et al., 1998). No
original data submitted.

Comments

Appendix H: NICEATM Table of Breakthrough Times

H-9
>4h

>4h

>4h

>4h

>4h

RP-40

RP-46

RP-49

RP-52

>4h

RP-33

RP-39

>4h

RP-29

>4h

>4h

RP-26

RP-34

38.35

propionic acid

36.22

19.20

38.98

37.57

Time 1 Time 2 Time 3 Time 4 Time 5 Time 6

19.17

CASRN

propionic acid

Chemical Name

37.78

19.19

Mean

1.19

0.02

Standard
Deviation
Comments

Appendix H: NICEATM Table of Breakthrough TimesH-10

sodium hydrogen fluoride

497-19-8

sodium carbonate (50% aq.)

71.57

>4h

RP-81B

7631-90-5>4hRP-80Bsodium bisulfite; sodium
sulfite carbonate

>4h

RP-62

144-55-8

>4h

RP-61

sodium bicarbonate; sodiumhydrogen carbonate

>4h

RP-57

71.17

Time 1 Time 2 Time 3 Time 4 Time 5 Time 6

>4h

CASRN

RP-53

Chemical Name

71.37

Mean

0.28

Standard
Deviation

Source: ECVAM Validation Study(Fentem et al., 1998). No
original data submitted.

Source: ECVAM Validation Study(Fentem et al., 1998). No
original data submitted.

Source: ECVAM Validation Study(Fentem et al., 1998). No
original data submitted.

Comments

Appendix H: NICEATM Table of Breakthrough Times

H-11

17.65

15.80

15.13

>4h

sodium hydroxide/SMS (1:10)

sodium hydroxide/SMS (5:3)

sodium hydroxide/tx 100

sodium hypochlorite w/ 5%
chlorine

69.65

138.80Solcenic 2BW

Solcenic 3A

3398-33-2

24.87

sodium hydroxide/SMS(0.5:1)

sodium undecylenate

32.13

sodium hydroxide/sodium
dodecyl sulfate (SDS) (1:10)

138.75

69.60

15.32

15.38

17.67

24.80

32.07

34.30

69.53

69.67

69.56

69.68

Time 1 Time 2 Time 3 Time 4 Time 5 Time 6

34.35

CASRN

sodium hydroxide/N,N'­bis(acrylyl)cystamine (BAC)(1:10)

Chemical Name

138.78

69.62

15.23

15.59

17.66

24.84

32.10

34.32

Mean

0.04

0.06

0.13

0.30

0.01

0.05

0.04

0.04

Standard
Deviation

Source: ECVAM Validation Study(Fentem et al., 1998). No
original data submitted.

Comments

Appendix H: NICEATM Table of Breakthrough Times

7664-93-9

sulfuric acid (10% wt.)

H-12
77.58

61790-33-8

tallow amine

Tide

16.93

9002-93-1

sulfuric acid + Triton x-100

56.27

16.22

sulfuric acid + SDS

TBQ

15.05

15.08

22.63

70.23

62.35

56.22

16.78

16.08

14.92

14.92

22.63

70.18

70.12

70.10

70.08

70.06

Time 1 Time 2 Time 3 Time 4 Time 5 Time 6

sulfuric acid + ferric chloride

sulfuric acid + Cellusolve5329-14-6

CASRN

sulfamic acid; midosulfonicacid

Solcenic 3B

Chemical Name

69.96

56.25

16.86

16.15

14.98

15.00

22.63

70.13

Mean

10.77

0.04

0.11

0.09

0.09

0.12

0.00

0.06

Standard
Deviation

Source: ECVAM Validation Study(Fentem et al., 1998). No
original data submitted.

Source: ECVAM Validation Study(Fentem et al., 1998). No
original data submitted.

Comments

Appendix H: NICEATM Table of Breakthrough Times

>4h

34.45

75.33

31.42

trichloro-toluene

Windex BlueZFAZWS 9352

177.87

H-13
31.53

70.48

35.18

177.7534.70

Time 1 Time 2 Time 3 Time 4 Time 5 Time 6

>4h

CASRN

tributylamine

Toilet Duck Green

Chemical Name

31.48

72.91

34.78

177.81

Mean

0.08

3.43

0.37

0.08

Standard
Deviation
Comments

Appendix H: NICEATM Table of Breakthrough Times

H-14

Appendix I

NICEATM1 Evaluation of the Performance of Corrositex® and the pH Test
The tabulated data as shown in the List of
Chemicals (Appendix A) were used to compare
the performance of Corrositex® and the pH Test;
both of the tests were compared against in vivo
data. Only those chemicals for which pH wasavailable were used in the analysis. Addition­
ally, any chemicals that produced discordantresults between papers/submissions or had dis­cordant results in multiple labs within the same
study were not included in this analysis.

Also included in this section are graphs of the
distribution of chemicals over the entire pH
range. The first graph depicts the distributionof pH for the entire data set (Submission,
Prevalidation Study [Botham et al., 1995],
ECVAM Validation Study [Fentem et al., 1998],
and Gordon et al., 1994). The next two graphs
depict the distribution of pH for the chemicals
provided in the Submission and the ECVAM
Validation Study, respectively.

1

NICEATM = National Toxicology Program (NTP) Interagency Center for the Evaluation of Alternative Toxicologi­
cal Methods

I-1

51

pH Test vs. In Vivo

44

pH Test vs. In Vivo

I-2

22

pH Test vs. In Vivo

85

(23/27)(26/27)(9/16)(14/15)(18/22)(17/17)(21/44)(20/30)(48/51)(48/51)

Accuracy
Number

100

100

0

100

0

100

0

55

100

100

(23/23)(23/23)

(0/7)

(7/7)

(0/4)

(4/4)

(0/23)(11/20)(48/48)(48/48)Sensitivity%
Number

0

75

100

88

100

100

100

90

0

0

(0/4)

(3/4)

(9/9)

(7/8)

(18/18)(13/13)(21/21)(9/10)

(0/3)

(0/3)

Specificity%
Number

85

96

88

100

92

94

94

(23/27)(23/24)

NA

(7/8)

NA

(4/4)

NA

(11/12)(48/51)(48/51)

Positive Predictivity%
Number

100

56

100

82

100

48

50

NA

(3/3)

(9/16)(7/7)(18/22)(13/13)(21/44)(9/18)NA

NA

Negative Predictivity%
Number

For the purposes of this analysis, a chemical/compound was deemed corrosive in the pH Test if that chemical/compound had a pH less than or equal to 2 or greater than or equal to 11.5 (40 CFR 158.690).

27

pH Test vs. In Vivo

96

56

93

82

100

48

67

94

94

%

100

25

0

13

0

0

0

10

100

100

(4/4)

(1/4)

(0/9)

(1/8)

(0/18)(0/13)(0/21)(1/10)

(3/3)

(3/3)

False Positive Rate%
Number

0

0

100

0

100

0

100

45

0

0

(0/23)(0/23)

(7/7)

(0/7)

(4/4)

(0/4)

(23/23)(9/20)(0/48)(0/48)

False Negative Rate%
Number5

One chemical (n -nonanol) was nonqualifying in Corrositex®, and was therefore, not included.

One chemical (potassium hydroxide) was not included in the either of the following comparisons because discordant in vivo results were obtained.
Abbreviations: NA = not applicable

4

3
One chemical (2,4-xylidine) was not included in this analysis because discordant Corrositex® results were obtained. Four chemicals were nonqualifying in Corrositex®, and were therefore, not included (4-amino-1,2,4-triazole; butylbenzene; 4-(methylthio)benzaldehyde; n ­undecanol).

2
One chemical (hexanoic acid) was not included in this analysis because discordant Corrositex® results were obtained. Thirteen chemicals were nonqualifying in Corrositex®, and were therefore, not included (isostearic acid; n -butyl propionate; isopropanol; phenethyl bromide; 2­phenylethanol; o -methoxyphenol guiacol; 2-bromobutane; 2-ethoxyethyl methacrylate; methyl trimethylacetate; methyl laurate; sodium lauryl sulfate; carvacrol; and 2-tert -butylphenol).

1

27

Corrositex ® vs. In Vivo

5

16

pH Test vs. In Vivo

For Chemicals with a pH > 11.5

15

Corrositex ® vs. In Vivo 4

For Chemicals with a pH between 8 and 11.5

17

Corrositex ® vs. In Vivo 3

For Chemicals with a pH between 4 and 830

Corrositex ® vs. In Vivo 2

For Chemicals with a pH between 2 and 4

51

Number ofChemicals

Corrositex ® vs. In Vivo

For Chemicals with a pH <2

Comparison

NICEATM Evaluation of the Performance of the Corrositex® and the pH Test1 in Predicting Corrosivity/Noncorrosivity Compared to In Vivo Findings

Appendix I: NICEATM Evaluation of the Performance ofCorrositex® and the pH Test

Number of Chemicals

Number of Chemicals

I-3

0

5

10

15

20

25

30

35

0

21

1

20

2

15

3

10

4

29

5

8

6

6

pH

7

4

8

11

9

2

10

3

Distribution of pH for the Entire Data Set

11

3

12

12

13

11

14

4

Appendix I: NICEATM Evaluation of the Performance ofCorrositex® and the pH Test

Numberofof Chemicals
Chemicals
Number

I-4

0

1

2

3

4

5

6

7

8

9

10

0

9

1

8

2

5

3

3

4

6

5

2

6

1

pH

7

8

8

9

1

10

1

11

2

Distribution of pH for the Chemicals provided in the Submission

12

5

13

7

14

1

Appendix I: NICEATM Evaluation of the Performance ofCorrositex® and the pH Test

Number of Chemicals

Number of Chemicals

I-5

0

2

4

6

8

10

12

14

0

1

4

2

4

3

4

12

5

2

6

pH

7

8

8

9

10

1

11

12

2

Distribution of pH for the Chemicals provided in the ECVAM Validation
Study

13

2

14

Appendix I: NICEATM Evaluation of the Performance ofCorrositex® and the pH Test

I-6

Appendix J

NICEATM1 Description of the Data Set used to Evaluate the Performance ofCorrositex® and the pH Test at Varying pH Levels
The following information describes the data set that was used to evaluate the performance of theCorrositex® Test and the pH Test for corrosivity versus in vivo results. This is a subset of the data
provided in Appendix A.
pH less than or equal to 2
Total number of chemicals with pH data = 51
Number of chemicals that are discordant between in vivo and Corrositex® results = 3
Number of chemicals that are discordant between in vivo and pH results = 3
Breakdown of discordant results:
Chemicalginmaleic acidsulfamic acid

Chemical/Product Class
Industrial Chemicalorganic acidinorganic acid

In Vivo-

Corrositex
+
+
+

pH
+
+
+

Abbreviations: - = noncorrosive, + = corrosive

pH between 2 and 4
Total number of chemicals with pH data = 44
Number of chemicals that are discordant between in vivo and Corrositex® results = 10
Number of chemicals that are discordant between in vivo and pH results = 22
Breakdown of discordant results:
Chemicalacrylic acidferrous chloride tetrahydrate
butyric acidacetic acidcrotonic acid
dimethylcarbamyl chloride
aluminum chloride
butyric anhydridehydroxylamine sulfate
2-methylbutyric acid

Chemical/Product Class In Vivo
organic acid+acid derivative+
organic acid+organic acid+organic acid+acid derivative+acid derivative+acid derivative
+
amine
+
organic acid+

Corrositex
+
+
+
+
+
+
+
+
+
+

pH
­
­
­
­
­
­
­
­
­
­

benzyl chloroformateacid derivative

-

­

+

1

NICEATM = National Toxicology Program (NTP) Interagency Center for the Evaluation of Alternative Toxicologi­
cal Methods

J-1

Appendix J: Data Set Used in pH Comparative Analyses

Chemicalcaprylic acidcapric/caprylic acidmethacrolein
octanoic acid65/35 octanoic/decanoic acids
55/45 octanoic/decanoic acids
60/40 octanoic/decanoic acids
allyl bromide

Chemical/Product Class In Vivo
organic acid+organic acid+aldehyde+organic acid+organic acid+organic acid+organic acid+industrial chemical+

Corrositex
-

pH
­
­
­
­
­
­
­
­

Copper (II) chloride

acid derivative

-

+

­

isostearic acidn-butyl propionate
isopropanol
phenethyl bromide
2-phenylethanolo-methoxyophenol guaiacol
2-bromobutane
2-ethoxyethyl methacrylate
methyl trimethylacetate
methyl laurate
sodium lauryl sulfate

organic acidneutral organic
neutral organic
alkyl halide
neutral organicorganic acidindustrial chemicalindustrial chemicalindustrial chemical
surfactant
soap/surfactant

-

nq
nq
nq
nq
nq
nq
nq
nq
nq
nq
nq

­
­
­
­
­
­
­
­
­
­
­

carvacrol
2-tert-butylphenolorganic acidorganic acid

+
+

nq
nq

­
­

hexanoic acidorganic acid+discordant­Abbreviations: - = noncorrosive, + = corrosive, nq = nonqualifying

pH between 4 and 8
Total number of chemicals with pH data = 22
Number of chemicals that are discordant between in vivo and Corrositex® results = 0
Number of chemicals that are discordant between in vivo and pH results = 3
Breakdown of discordant results:
Chemicalammonium hydrogen difluoride
sulfur monochloride
1-(2-aminoethyl)piperazine

Chemical/Product Class In Vivoacid derivative+acid derivative
+
amine
+

Corrositex
+
+
+

pH
­
­
­

4-amino-1,2,4-triazole
butylbenzene
4-(methylthio)benzaldehyde
n-undecanolamine
industrial chemical
aldehydeindustrial chemical

-

nq
nq
nq
nq

­
­
­
­

2,4-xylidine

amine

-

discordant­Abbreviations: - = noncorrosive, + = corrosive, nq = nonqualifying

J-2

Appendix J: Data Set Used in pH Comparative Analyses

pH between 8 and 11.5
Total number of chemicals with pH data = 16
Number of chemicals that are discordant between in vivo and Corrositex® results = 1
Number of chemicals that are discordant between in vivo and pH results = 7
Breakdown of discordant results:
Chemical
1,2-diaminopropane
dimethyldipropylenetriamine
dimethylisopropylamine
n-heptylamine
dicyclohexylamine
3-methoxypropylamine
N,N-dimethylbenzylamine

Chemical/Product Class In Vivo
amine
+
amine
+
amine
+
amine
+
amine
+
amine
+
amine
+

Corrositex
+
+
+
+
+
+
+

pH
­
­
­
­
­
­
­

n-nonanol

industrial chemical

-

nq

­

triethanolamine

amine

-

+

­

Abbreviations: - = noncorrosive, + = corrosive, nq = nonqualifying

pH greater than 11.5
Total number of chemicals with pH data = 28
If pH 11.5 is used as the cutoff for corrosivity:
Number of chemicals that are discordant between in vivo and Corrositex® results = 1
Number of chemicals that are discordant between in vivo and pH results = 4
Breakdown of discordant results:
Chemicalsodium hypochlorite w/ chlorine
calcium carbonate
degreaser

Chemical/Product Class In Vivoacid derivativeacid derivative
degreaser-

Corrositex
-

pH
+
+
+

sodium carbonate

inorganic base

-

+

+

potassium hydroxide

inorganic basediscordant

+

+

J-3

Appendix J: Data Set Used in pH Comparative Analyses

If pH 12.5 is used as the cutoff for corrosivity:
Number of chemicals that are discordant between in vivo and Corrositex® results = 1
Number of chemicals that are discordant between in vivo and pH results = 12
Breakdown of discordant results:
Chemicalcalcium carbonate
degreaser

Chemical/Product Class In Vivoacid derivative
degreaser-

Corrositex
-

pH
+
+

sodium carbonate

inorganic base

-

+

­

lithium hydroxide monohydrate
ethanolamine
tetraethylenepentamine
triethylenetetramine
2-ethylhexylamine
2-mercaptoethanol, sodium salt
diethylamine
diethylenetriamine
ethylenediamine
cyclohexylamine

inorganic base
amine
amine
amine
amine
inorganic base
amine
amine
amine
amine

+
+
+
+
+
+
+
+
+
+

+
+
+
+
+
+
+
+
+
+

­
­
­
­
­
­
­
­
­
­

potassium hydroxide

inorganic basediscordant++Abbreviations: - = noncorrosive, + = corrosive, nq = nonqualifying

J-4

Appendix K

NICEATM1 Assessment of the Performance of Corrositex® Compared to the
Performance of the pH Test for Test Materials in the Extreme pH Ranges
In an effort to evaluate the usefulness ofCorrositex® compared to the pH Test for test
materials with pH values in the extreme ranges(i.e., pH ≤ 2.0 and pH ≥ 11.5), the database of
test materials used in the analysis provided inAppendices I and J was expanded to include
information from the following sources:

Corrositex system: A DOT accepted method
to predict corrosivity potential of test mate­rials. Alternative Methods Toxicol. 10:37­
45.

• InVitro International, Inc. Corrositex®
ICCVAM Submission, May, 1998•

• Fentem, J. H., G. E. B. Archer, M. Balls, P.
A. Botham, R. D. Curren, L. K. Earl, D. J.
Esdaile, H.-G. Holzhütter, and M. Liebsch.
1998. The ECVAM international validation
study on in vitro tests for skin corrosivity.
2. Results and evaluation by the manage­
ment team. Toxicol. In Vitro 12:483-524.

October, 1996 Corrositex® ICCVAM Sub­mission, provided by InVitro International,
Inc. [Please note: Supporting data sheets
for Corrositex® and in vivo data were notprovided for the test materials in this sub­mission; quality assurance analysis was notconducted on these results.]• Gordon, V. C., J. D. Harvell, and H. I.
Maibach. 1994. Dermal corrosion, the1

NICEATM = National Toxicology Program (NTP) Interagency Center for the Evaluation of Alternative Toxicologi­
cal Methods

K-1

Appendix K: NICEATM Comparative Assessment for Extreme pH Ranges

Table 1. Summaryof Results
TestforMaterials
withwitha pHa pH≤ 2.≤ 2.
Table 1. Summaryof forResults
Test Materials
In Vivo
+
-

pH
+
+
+
+
+

Corrositex++
discordant 1
nonqualifying

Number of Test Materials
102
13
6a
b
1
c
1

a

The six test materials were as follows, with test concentrations in parentheses: chemical #9, citricacid (5%), citric acid (10%), citric acid (14.6%), ferric chloride (2%), and oxalic acid (10%).
b
The discordant test material was identified as chemical #83151 (a petrochemical).
c
The nonqualifying chemical was methyl myristate.
Table 2. Summary of Results for Test Materials with a pH ≥ 11.5.

In Vivo++
discordant
-

pH
+
+
+
+
+
+

Corrositex+++
discordant

Number of Test Materials
100
2a
2b
29
10c
d
1

a

The two test materials were cellusolve/SMS (20/1%) and Cleaner #13.
The test materials that were discordant based on in vivo tests were potassium hydroxide (5%) andsodium hydroxide (5%).
c
The 11 test materials were as follows, with test concentrations in parentheses: bathroom cleaner,bathroom cleaner #2, calcium carbonate (neat), three different cleaners, degreaser, sodium hydrox­ide (0.1%), sodium hypochlorite (5%), and sodium metasilicate (2%).
d
The test material that was discordant in Corrositex tests was cleaner #14.
b

Table 3. Summary of Results for Test Materials with a pH ≤ 2 or ≥ 11.5.
In Vivo++
discordant

pH
+
+
+
+
+
+
+

Corrositex++
discordantnonqualifying+

Number of Test Materialsa
202
2
42
16
2
1
2

a

Please see the footnotes to Tables 1 and 2 for specific test material information.

1

Different labs within a study and/or source papers reported different results.

K-2

K-3

262
265

121
123

141
142

Comparison

Total Data Set
Corrositex® vs. In Vivo
pH vs. In Vivo

pH ≤ 2
Corrositex® vs. In Vivo
pH vs. In Vivo

pH ≥ 11.5
Corrositex® vs. In Vivo
pH vs. In Vivo
78%
72%

89%
83%

83%
77%

%

(110/141)(102/142)(108/121)(102/1230(218/262)(204/265)

Number

Accuracy 1

98%
100%

100%
100%

99%
100%

%

(100/102)(102/102)(102/102)(102/102)(202/204)(204/204)

NumberSensitivity 2

26%
0%

32%
0%

28%
0%

%

(10/39)(0/40)(6/19)(0/21)(16/58)(0/61)

NumberSpecificity 3

78%
72%

90%
83%

83%
77%

%

4

(100/129)(102/142)(102/113)(102/123)(202/244)(204/265)

NumberPositive Predictivity

83%
NA

100%
NA

89%
NA

%

Positive Predicitivity: The proportion of correct positive responses among materials testing positive.

Negative Predictivity: The proportion of correct negative responses among materials testing negative.

False Positive Rate: The proportion of all negative (noncorrosive) test materials that are falsely identified as positive.

False Negative Rate: The proportion of all positive (corrosive) test materials that are falsely identified as negative.

5

6

7

Specificity: The proportion of all negative test materials that are correctly classified as negative in a test.

3

4

Sensitivity: The proportion of all positive test materials that are correctly classified as positive in a test.

2(10/12)
(0/0)

(6/6)
(0/0)

(16/18)(0/0)

Number

Negative Predictivity5

Accuracy: (a) The closeness of agreement between a test result and an accepted reference value. (b) The proportion of the correct outcomes of the method. Often used interchangeably with concordance.

1

Numberof TestMaterials

74%
100%

68%
100%

72%
100%

%

(29/39)(40/40)(13/19)(21/21)(42/58)(61/61)

NumberFalse Positive Rate6

Table 4. Performance of Corrositex and the pH Test as compared to In Vivo Findings for Test Materials in the Extreme pH Ranges (i.e., pH ≤ 2 and pH ≥ 11.5)

2%
0%

0%
0%

1%
0%

%

(2/102)(0/102)(0/102)(0/102)(2/204)(0/204)

NumberFalse Negative Rate7

Table 4. Performance of Corrositex® and the pH Test as Compared to In Vivo Findings for Test Materials in the Extreme pH Ranges(i.e., pH ≤ 2 and pH ≥ 11.5)

Appendix K: NICEATM Comparative Assessment for Extreme pH RangesL-1
I
I
II
I

Acid
derivative
Acid
derivative

Amine/organic
base

Amine/organicbase

Organic ac id

Hexanoic acid3
I II

II

II

II

II

R34/II & III

R3 5/I

R 34/II

R35/I

R35/I

R 34/IINC

R34/II

R35/I

In Vivo

NC

R34

R34

R35

R35

R35

R34

R34

R35

L ab 4 –
Run 1

NC

R34

R34

R35

R35

R35

R34

R34

R35

NC

R34

R34

R35

R35

R34

R34

R34

R35

NC

R34

R34

R35

R35

R34

R34

R34

R35

ECVAM Validation Study
L ab 4 – Lab 5 –Lab 5 –Run II
Run 1
Run II

R34

R34

R34

R35

R35

R34

R34

R34

R35

L ab 6 –
Run 1

R34

R34

R34

R35

R35

R34

R34

R34

R35

L ab 6 –Run I I2

NICEATM = The National T oxicology Program (NTP) Interagency Cent er for the Evaluation of Alterna tive Toxicological Methods
ECVAM = T he European Centre for the Validation of Alternative Methods
3
Hexanoic acid was also tested by two labs as part of the E CVAM Prevalidation Study. (Botham et a l., 1995) Both labs found th echemical to be corrosive, but no packing group was assigned.
Abbrev iations: NC = Noncorrosive; I = US Department of Transportation (DOT) Packing Group I; II = US DOT Packing Group II; III= US DOT Packing Group III; R34 = United Nations (UN) Packing Groups II & III; R35 = UN Packing Group I.

1

I

II

Acid
derivative

C

I

NC

Inorga nic acid

II

II

Inorga nic acid

I

Corrositex

I

In Vivo

Submission

Inorga nic acidChe mical
Class

Boron
trifluoride
dihydrate
Phosphoric acidSulfamic acid;midosulfonicacid
Ferric chloride;iron (III)chloride
Phosphorus
pentachloride
Phosphorus
tribromide
1- (2­
aminoe thyl )piperazine
1,2 –diaminopropane

Chemica l
Name

NICEATM1 Summary of Results for Chemicals that Were Tested in Both the Submission and the
ECVAM2 Validation Study (Fentem et al., 1998)

Appendix L

L-2

Appendix M

NICEATM Evaluation of the Performance of Corrositex® in
Predicting Corrosivity/Noncorrosivity Compared to In Vivo Findings
The following provides an overview of the per­formance of Corrositex® using the following
sources: 1998 IVI Submission, Fentem et al.
(1998), and Gordon et al. (1994). Chemicals
mentioned only in the Botham et al. (1995) were
specifically excluded at the request of the Peer
Review Panel (PRP). This data set is an addi­
tion to Table 5 (page 21 of the Peer Review
Panel [PRP] report).

As compared to the performance characteris­tics for the entire data set Table 5 (page 21 of
the PRP report) the accuracy of the data set ex­cluding the Botham et al. (1995) paper was
slightly higher (87% as compared to 84%).
Similarly sensitivity and specificity were alsoslightly higher for this data set (sensitivity =92% as compared to 89%; specificity = 78% ascompared to 75%).

1

NICEATM = National Toxicology Program (NTP) Interagency Center for the Evaluation of Alternative Toxicologi­
cal Methods

M-1

8%

(10/120)M-2

8Chemicals from the following sources were included in this analysis: 1998 Submission, Fentem et al. (1998), and Gordon et al. (1994). See Appendix A of this report for complete citations of theseA S of this report for complete citations of these
Chemicalssources. from the following sources were included in this analysis: 1998 Submission, Fentem et al. (1998), and Gordon et al. (1994). See Appendix
sources.

8

False Negative Rate: The proportion of all positive (corrosive) test materials that are falsely identified as negative.

(16/73)7

22%

False Positive Rate: The proportion of all negative (noncorrosive) test materials that are falsely identified as positive.

(57/67)

6

85%

Negative Predictivity: The proportion of correct negative responses among materials testing negative.

(110/126)

587%

Positive Predicitivity: The proportion of correct positive responses among materials testing positive.

(57/73)

4

78%

Specificity: The proportion of all negative test materials that are correctly classified as negative in a test.

(110/120)

3

92%

False Negative Rate 7%
NumberSensitivity: The proportion of all positive test materials that are correctly classified as positive in a test.

(167/193)

Specificity 3
Positive Predictivity 4 Negative Predictivity 5 False Positive Rate 6%
Number%Number%Number%Number2

87%

Sensitivity 2%
NumberFindings

Accuracy: (a) The closeness of agreement between a test result and an accepted reference value. (b) The proportion of the correct outcomes of the method. Often used interchangeably with concordance.

193

RevisedData Set8

Accuracy 1%
Number

In Vivo1

Number ofChemicals

Data
SourceTable 1a. Evaluation of the Performance of the Corrositex Test in Predicting Corrosivity/Noncorrosivity Compared to

Evaluation of the Performance of Corrositex® in Predicting Corrosivity/Noncorrosivity Compared to In Vivo Findings (Overall)Appendix M: Corrositex® Performance Evaluation

Appendix N

Quality Assurance Audit Summaries
NICEATM1 Verification of Data in Appendix IV of the May 1998 Submission Based on
Confidential Laboratory Notebooks Provided by the Sponsor and the ECVAM2 Validation Study(Fentem et al., 1998)
In Vivo Data (Appendix V)

For compound 80, named “485,” the notebook
gives a mean breakthrough time of 55.22 min­utes. The value in Appendix IV of the Submis­
sion (28.25 minutes) was given for “485B” inthe laboratory notebook.

Handwritten data in the original laboratory note­books substantiated the in vivo packing grouplabel except for compounds numbered 1, 8, and9 in Appendix IV of the Submission. The note­books did contain typewritten summaries withthe appropriate data (tissue destruction/irrevers­
ible changes within 3 minutes).

For compound 94, Appendix IV of the Submis­
sion gives a mean breakthrough time of 40.29
minutes whereas the laboratory notebook pagecited gives a value of 35.62 minutes.

The laboratory notebook sample numbers des­ignated for the compounds in Appendix IV of
the Submission are sometimes incorrect. For
compound 40 in Appendix IV, the laboratory
notebook sample number is 60; for compound
51, #21; for compound 60, #49; for compound
66, #32; for compound 71, #64; for compound
73, #45; for compound 78, #19; for compound
80, #12; for compound 82, #10; for compound
83, #11. For compounds 88, 89, 90, 91, and 95,
the notebook sample numbers are 62, 61, 63,
46, and 44, respectively.

None of the differences noted above wouldchange the packing group designations.
All of the packing group designations are ap­
propriately assigned for the Corrositex® results(mean breakthrough times).
All other mean breakthrough times were accu­
rately reproduced from the laboratory notebookdata.
All designations in the Category column under
Corrositex® Results (except NF and NA) were
accurately reproduced from the laboratory note­books.

ECVAM Validation Study Results
The European Union (EU) risk phrase listed for
the Corrositex® results in Appendix IV of theSubmission for compound 45 is R34. However,in the table of data on page 46 of the ECVAM
report by Fentem et al. (1998), 2 of the 3 labo­
ratories listed R35.

Data audit conducted by Bonnie Carson, ILS,
Inc./NICEATM on July 28, 1998.

Corrositex® Laboratory Notebook Data (Ap­pendix VI) of the Submission
For compound 13, the mean breakthrough time
given in Appendix IV is 71.57 minutes.
The notebook gives 71.37 minutes.
1

NICEATM = National Toxicology Program (NTP) Interagency Center for the Evaluation of Alternative
Toxicological Methods
2
ECVAM = European Centre for the Validation of Alternative Methods

N-3

Appendix N: Quality Assurance Audit Summaries

NICEATM Summary Comments on NIEHS3 Auditof the May, 1998 Corrositex® ICCVAM Submission
ing studies (as provided in the test reports [TR]and Appendix IV) and in vitro studies (as re­ported in Appendix IV). Information pertain­
ing to test dates, animal strain and supplier,sample numbers and/or chemical name, concen­
tration, times of exposure, and dermal reactions
were verified in the in vivo test reports. The
information in the in vivo test reports was thencompared with the tabulated in vivo summary
results in Appendix IV. Information pertaining
to reaction time in the Corrositex® system,
Corrositex® category, and packing group des­ignation for in vitro study results in Appendix
IV were verified from corresponding notebooks
in Appendix VI. For in vitro studies, the pack­ing group classifications were verified from thepacking group designation table on page 6 ofAppendix X. A total of 118 chemical samples
were tabulated in Appendix IV, of which origi­
nal data were present for 95 chemical samples.

At the request of NICEATM, the NIEHS Qual­
ity Assurance Unit (QAU) conducted an auditof Sponsor-submitted information to determine
the accuracy, consistency, and completeness ofthe transcribed summary tables as compared tothe original study records. Confidential in vivo
and in vitro data associated with the validation
studies of the Corrositex® test system were com­pared against the summary tables in the May,
1998 Corrositex® Submission. The audit was
conducted from September 4, 1998 throughOctober 2, 1998. The following comments pro­vide a summary of the information determined
during the course of that audit.
A. Audit procedures and scope
Several points must be considered regarding theaudit. As stated in both the Submission and theaudit, neither the in vivo or in vitro segments of
the report were conducted under full Good
Laboratory Practice (GLP) compliance.
Records concerning a number of areas were notavailable and not considered during the audit.
These include animal receipt, quarantine, ran­domization, and serology; animal husbandry
and environmental controls; test chemical re­ceipt, inventory and usage; test chemical iden­tity and purity; dose preparation analysis; stan­
dard operating procedures; instrument calibra­
tions; and chemical-specific protocols, amend­
ments, and deviations. Since the objective of
the audit was to assess the extent to which sum­
marized in vitro and in vivo test information was
supported by hand-written source data and otherrecords, the following audit procedures on the
Submission were performed.

B. Assessment
In assessing the audit report, NICEATM staff
focused on audit findings that would impact the
integrity of the data and the ability of the Peer
Review Panel (PRP) to properly evaluate thedata in the Submission. The majority of audit
findings related to transcriptional errors or thelack of full documentation on test records.
Whereas these errors demonstrate lack of com­pleteness and/or GLP compliance within the
Submission package, they do not effect the in­tegrity of the data or an ability to assess perfor­
mance of the data presented. Of more impor­tance are cases where audit findings would
modify actual Corrositex® results, packing
group designation, or category designations. In
general, the audit findings showed that (a) mean
breakthrough times are accurately produced

Audited data included all pertinent data and fac­
tual information applicable to the in vivo screen­
3

NIEHS = National Institute of Environmental Health Sciences
N-4

Appendix N: Quality Assurance Audit Summaries

ber of cases of transcriptional errors were iden­tified and the lack of documentation complete­ness in the Submission was noted. NICEATM’s
assessment of the audit report found that mostof the findings are inconsequential to the over­
all Submission. There were a few cases where
designation of Corrositex® data could be af­
fected. However, correction of data entries inthese few cases does not affect the overall as­
sessment of the Submission because thesechanges would either slightly alter or have noeffect on the evaluation of concordance, speci­
ficity, sensitivity, positive or negative
predictivity, or false positive or false negative
rates. Whereas the auditors’ findings may re­sult in a lowering of confidence in the data pre­sented in the Submission, they do not appear tohave significant impact on the assessment andevaluation of the test submission.

from laboratory notebook data, (b) packing
group designations are appropriately assigned
for mean breakthrough times, and (c) designa­
tions in the category column under Corrositex®
results are accurately reproduced from the labo­
ratory notebooks. Most of the recording errors
noted in the audit would not alter packing group
designations or Corrositex® results.
There were only a few instances where audit
findings did affect packing group designations
or Corrositex® results. In vivo Packing Group
designation for sodium hydroxide (NaOH)/SMS
was listed as corrosive (C) in the study report
whereas the original study records list “incon­
clusive” as the result. The in vitro packing groupfor butylamine was entered in the report as “III,”but original study records reported it as “II”. In
vitro Corrositex® time (minutes) for sample
name 485 (sample number 50) was shown to
be 55.22 minutes in the original study records
but was listed as 28.25 minutes in the report
entry. This would modify the packing group
designation in the report for compound 485 from
Packing Group designation II to category III.

*Note that on October 27, 1998, NICEATM sent
the auditors report to the Sponsors for them toclarify and respond to the audit findings. The
Sponsors acknowledged the errors, but addedthat these would have minimal effect on theoverall data assessment.

In summary, the audit noted that the studies were
not conducted under GLP compliance. A num­

N-5

N-6

Appendix O

Evaluation Guidance to the Peer Review Panel
A. Instructions for Peer Review Panel (PRP) Members
The PRP was charged with developing a consensus on the usefulness of Corrositex® as an alterna­
tive method to the in vivo methods that are commonly used for assessing dermal corrosivity. In
reaching this determination, the PRP was asked to evaluate all of the available information in the
Submission in accordance with the published criteria for validation and acceptance of toxicologicaltest methods (NIEHS, 1997). The PRP was charged with preparing a written report that summa­
rized the extent to which each of these criteria have been addressed.
An outline of the major items that were addressed in the PRP report is provided below in “B. Points
for Evaluation.” Specific questions or considerations that were addressed by the reviewers in theirassessment were added by the Corrosivity Working Group (CWG) to ensure that the assessment
provided adequate information to facilitate agency decisions on the regulatory acceptability of themethod.
One primary and at least two secondary reviewers were designated for each section by the National
Toxicology Program (NTP) Interagency Center for the Evaluation of Alternative Toxicological
Methods (NICEATM) in consultation with the PRP Chair. These individuals were requested toprepare written responses for their assigned sections. However, all reviewers were encouraged tofamiliarize themselves with the entire set of questions and to comment on any (or all) section(s).
All reviewers were asked to complete the summary conclusions section (Section C of this Appen­dix).
In conducting this review, the primary focus of the PRP was to evaluate the proposed Corrositex®
protocol and supporting submission materials. Based on the supporting information provided in
the Submission, the PRP was asked the extent to which Corrositex® is an acceptable alternative tostandard in vivo dermal corrosivity assays for identifying human corrosives. The review focusedon the following:
Has Corrositex® been evaluated sufficiently and is its performance satisfactory to support
its proposed use for assessing the dermal corrosivity potential of substances?
Does Corrositex® offer advantages with respect to animal welfare considerations (re­finement, reduction, and replacement)?
The focus of the PRP evaluation was on the utility of Corrositex®, as described in the proposed
Instruction Manual (Appendix D) for detecting possible human corrosives. Suggestions for futureevaluations or workshops to review proposed test method revisions or other test methods were
submitted to NICEATM for consideration by Interagency Coordinating Committee on the Valida­tion of Alternative Methods (ICCVAM) and were described in Section D, Related Issues.

O-1

Appendix O: Evaluation Guidance to the Peer Review Panel

B. Points for Evaluation
1. Test Method Descriptiona.

b.

Are the test method and protocol described in sufficient detail, including the scientificand mechanistic basis of the test, range of applications, endpoints, numbers of
replicates, need for dose-response curves, and acceptable variations in the protocol?
1)

Is the protocol used to generate the supporting submission data in agreementwith the proposed protocol? If not, discuss the adequacy of the rationale
provided for changes incorporated in the proposed protocol.

2)

Evaluate the appropriateness of the dose and breakthrough time selection
procedure. Discuss the need for determination of categorization or
acute toxicity data prior to conducting the actual test.

Comment on the adequacy and completeness of the test method protocol, including:1)

Description of the material and equipment needed to conduct the test. Is thenumber of tests per test agent appropriate?

2)

Description of what is measured and how it is used.

3)

Description of data analysis, evaluation, and decision criteria used to
identify substances as:- qualified or not qualified- category 1 or category 2- corrosive or noncorrosivec.

Are there appropriate provisions for the use of positive, negative, and [otherendpoints] control chemicals?

d.

What are the strengths and/or limitations of Corrositex® and are they described ad­
equately, including the usefulness for testing various chemical classes and/or mix­tures.

e.

Are there editorial/technical corrections necessary for the proposed protocol?

2. Test Method Data Quality
Is there evidence of sufficient quality assurance/quality control (i.e., were experiments con­ducted and data collected and maintained in accordance with Good Laboratory PracticeO-2

Appendix O: Evaluation Guidance to the Peer Review Panel[GLP] standards and procedures or in the “spirit” of GLPs [e.g., GLP standards without
audits])? If not, is there clear indication from the technical data that there was adequate
record-keeping or data collection.
a.

Is there an assurance provided that indicates there was adherence to the protocol
during the validation studies? Are deviations from the standard protocol clearly
described and justified?

b.

Was a data audit conducted by a Quality Assurance Unit? If so, is the data quality
satisfactory based on the audit results (e.g., adequate adherence to protocols, recordkeeping following GLPs)?

3. Test Method Performancea.

Are the data provided in sufficient detail for you to evaluate the results and conclusions
obtained with Corrositex®? Are sufficient data provided to adequately evaluate theperformance of the method for its proposed use?

b.

Does the method adequately predict the endpoint of interest (corrosivity) by demon­
strating a linkage between the test and the current test method (rabbit skin test)?

c.

Comment on the adequacy of the methods used to evaluate the suitability and per­formance of the test method. Are results of Corrositex® and the reference test(s)compared and evaluated appropriately?

d.

Comment on the adequacy of the statistical/analytical methods used to evaluate theperformance of the test method.

e.

Comment on the adequacy of the chemicals/products (numbers/types) selected toevaluate the performance of the method for each chemical/product class. Is it ap­
propriate to generalize the performance of the method for all chemicals/products ineach class based on the performance of the selected test chemicals/products?

f.

Comment on the sensitivity, specificity, concordance, false positive rate, and false
negative rates for the chemical/product classes that the method is proposed to be
used for.
1)

To what extent does the method classify corrosives correctly for thosethat qualify in the Chemical Detection System (CDS): for all chemi­
cals/products or some classes?

2)

To what extent does the method classify non-corrosives correctly for
those that qualify in the CDS: for all chemicals/products or someclasses?

O-3

Appendix O: Evaluation Guidance to the Peer Review Panel4.

g.

Are the sensitivity, specificity, concordance, and false positive and negative rates
acceptable for the chemical/product classes tested?

h.

Are the conclusions on the usefulness of this method scientifically sound?
1)

Are results of Corrositex® clinically relevant and is the test predictive forhuman corrosivity?

2)

Is the utility of the method clearly established for regulatory use in hazard
assessment of chemicals as potential corrosives?

Determination of Test Method Reliability (Repeatability/Reproducibility)
Are intra- and inter-laboratory reproducibility adequately evaluated?
a.

Comment on the adequacy of the evaluation of intralaboratory repeatability andreproducibility of the test method, and the data used to define and describe the levelof intralaboratory variability.

b.

Comment on the adequacy of the evaluation of interlaboratory reproducibility of thetest method, and the data used to define and describe the level of interlaboratory
variation.
1)

Consider the range of vehicle control data within and across laboratories inthe validation studies. Do these differences affect data quality (reproducibility,
sensitivity, etc)?

c.

Was the reproducibility of the test method evaluated on a series of appropriate
reference chemicals or products, and do these adequately represent the types ofsubstances for which the test method is proposed to be used?

d.

Are the results obtained with Corrositex® sufficiently repeatable and reproducible?

e.

Comment on the adequacy of the reproducibility and reliability of Corrositex®. How
does this compare to currently used methods for determining corrosivity.

5. Other Scientific Reviews
Comment on and compare the conclusions published in independent peer-reviewed reports
or other independent scientific reviews of the test method, compared to the conclusions
reached in this submission, and comment on any other ongoing evaluations of this method.

O-4

Appendix O: Evaluation Guidance to the Peer Review Panel

6. Other Considerationsa.

C.

Can the test method be readily transferred among properly equipped and staffedlaboratories; that is:1)

Is it relatively insensitive to minor changes in protocol (e.g., the acceptable
pH/temperature range for reagents and for the location where the test will be
conducted)?

2)

Are the level of training and expertise required to conduct the test reasonable?

3)

Are the necessary equipment and supplies relatively easy to obtain?

b.

Is the method cost-effective, relative to the cost of conducting an in vivo test or pH
extreme?

c.

Is the time needed to conduct the test reasonable?

d.

Is there any other information that should be added to the report, published or un­
published?

e.

Has there been adequate consideration and appropriate incorporation of animaluse refinement, reduction, and replacement alternatives? Will Corrositex® reduce
the number of animals required or refine the procedure to reduce or eliminate pain
or distress compared with the reference tests?

f.

How does the performance of this method compare to the current regulatory use of
pH extremes (pH<2.0 or >11.5) to classify and label a chemical or product as corro­
sive?

g.

Does the test method appear to be effective for assessing corrosivity/noncorrosivity
for CDS-qualified chemicals of any pH, those in the listed effective range of <5.0 or>8.5, or only for certain other pH ranges?

h.

Should pH determination be required prior to use of this test method?

Summary Conclusions
Based on the information provided:a.

Does this method adequately identify the dermal corrosivity potential forsome or all chemicals? Specify those for which it would be considered ad­
equate, and those for which it is not adequate.

O-5

Appendix O: Evaluation Guidance to the Peer Review Panelb.

Is this method adequate for identifying the absence of dermal corrosivity
potential for some or all chemicals? Specify those for which it would beconsidered adequate, and those for which it would not be considered ad­
equate.

c.

Could this method be used to provide equivalent or better prediction of
corrosivity or noncorrosivity for some or all chemicals than current meth­ods? If applicable, discuss how it should be used in conjunction with cur­rent methods.

d.

Discuss conditions/limitations/restrictions that may affect the intended useof Corrositex®, and that are justified based upon the presence or lack ofscientific evidence.

e.

Discuss advantages of the proposed Corrositex®, as compared to the stan­
dard corrosivity test methods.

f.

Has there been adequate consideration and appropriate incorporation of ani­
mal use refinement, reduction, and replacement alternatives? Will Corrositex®
reduce the number of animals required or refine the procedure to eliminate
pain or distress compared with the commonly used corrosivity tests.

D. Related Issues
1.

This evaluation is for a specific assay proposed as an alternative for currently ac­
cepted in vivo dermal corrosivity tests. Are there other test methods for this end­
point, or other endpoints that you would you like to see evaluated by ICCVAM in
the future?

2.

Are there suggestions/recommendations for workshops or validation efforts that you
think that ICCVAM or others should support in this area of corrosivity?

Reference:
NIEHS (National Institute of Environmental Health Sciences). 1997. Validation and regulatory
acceptance of toxicological test methods: A report of the ad hoc Interagency Coordinating Com­mittee on the Validation of Alternative Methods. NIH Publication No. 97-3981. NIEHS, Research
Triangle Park, NC.

O-6

Appendix P

ICCVAM1 Validation and Regulatory Acceptance Criteria
Validation Criteria2

description of the classes of materials thatthe test can and cannot accurately assess.

For a new or revised test method to be consid­
ered validated for regulatory risk assessment
purposes, it should generally meet the follow­
ing criteria (the extent to which these criteria
are met will vary with the method and its pro­
posed use). However, there needs to be flex­
ibility in assessing a method given its purpose
and the supporting database. Because tests canbe designed and used for different purposes bydifferent organizations and for different catego­ries of substances, the determination of whether
a specific test method is considered by anagency to be useful for a specific purpose must
be made on a case-by-case basis. Validation ofa test method is a prerequisite for it to be con­sidered for regulatory acceptance.
•

The scientific and regulatory rationale forthe test method, including a clear statementof its proposed use, should be available.

•

The relationship of the test method’s
endpoint(s) to the biologic effect of interest
must be described. Although the relation­
ship may be mechanistic or correlative, tests
with biologic relevance to the toxic process
being evaluated are preferred.

• The extent of within-test variability, and the
reproducibility of the test within and amonglaboratories must have been demonstrated.
Data must be provided describing the levelof intra- and interlaboratory reproducibility
and how it varies over time. The degree towhich biological variability affects this test
reproducibility should be addressed.
• The test method’s performance must havebeen demonstrated using reference chemi­cals or test agents representative of the typesof substances to which the test method will
be applied, and should include both known
positive and known negative agents. Un­less it is hazardous to do so, chemicals or
test agents should be tested under code to
exclude bias.
• Sufficient data should be provided to permit
a comparison of the performance of a pro­
posed substitute test with that of the test it
is designed to replace. Performance shouldbe evaluated in relation to existing relevant
toxicity testing data, and relevant toxicity
information from the species of concern.
Reference data from the comparable tradi­tional test method should be available andof acceptable quality.

• A detailed protocol for the test method must
be available and should include a descrip­tion of the materials needed, a descriptionof what is measured and how it is measured,
acceptable test performance criteria (e.g.,positive and negative control responses), a
description of how data will be analyzed, alist of the species for which the test results
are applicable, and a description of the
known limitations of the test including a• The limitations of the method must be de­scribed; for example, in vitro or other nonanimal test methods may not replicate all of
the metabolic processes relevant to chemi­
cal toxicity that occur in vivo.

1

ICCVAM = Interagency Coordinating Committee on the Validation of Alternative Methods
NIEHS (National Institute of Environmental Health Sciences). 1997. Validation and regulatory acceptance of
toxicological test methods: A report of the ad hoc Interagency Coordinating Committee on the Validation of
Alternative Methods. NIH Publication No. 97-3981. NIEHS, Research Triangle Park, NC.
2

P-1

Appendix P: ICCVAM Validation and Regulatory Acceptance Criteria• Ideally, all data supporting the validity of atest method should be obtained and reported
in accordance with Good Laboratory Prac­tices (GLPs). Aspects of data collection not
performed according to GLPs must be fully
described, along with their potential impact.
•

All data supporting the assessment of thevalidity of the test method must be
available for review.

•

Detailed protocols should be readily avail­able and in the public domain.

•

The method(s) and results should be pub­lished or submitted for publication in an in­
dependent, peer-reviewed publication.

••

Validated methods are not automatically ac­
cepted by regulatory agencies; they need to fit
into the regulatory structure. Flexibility is es­
sential in determining the acceptability of meth­ods to ensure that appropriate scientific infor­
mation is considered in regulatory risk assess­ment. A test method proposed for regulatory
acceptance generally should be supported by thefollowing attributes:•••

There should be adequate test data forchemicals and products representative of
those administered by the regulatory pro­gram or agency and for which the test is
proposed.

•

The method should generate data useful forrisk assessment purposes, (i.e., for hazard
identification, dose-response assessment,
and/or exposure assessment). Such meth­ods may be useful alone or as part of a bat­tery or tiered approach.

•

The specific strengths and limitations of thetest must be clearly identified and described.

•

The test method must be robust (relatively
insensitive to minor changes in protocol)and transferable among properly equippedand staffed laboratories.

•

The method should be time and cost effec­
tive.

•

The method should be one that can be har­monized with similar testing requirementsof other agencies and international groups.

•

The method should be suitable for interna­
tional acceptance.

•

The method must provide adequate consid­
eration for the reduction, refinement,
and replacement of animal use.

The methodology and results should havebeen subjected to independent scientific re­view

Regulatory Acceptance Criteria2

The method should have undergone inde­
pendent scientific peer review by disinter­
ested persons who are experts in the field,
knowledgeable in the method, and finan­cially unencumbered by the outcome of theevaluation.
There should be a detailed protocol withstandard operating procedures (SOPs), a list2

of operating characteristics, and criteria for
judging test performance and results.
Data generated by the method should ad­
equately measure or predict the endpoint ofinterest and demonstrate a linkage between
either the new test and an existing test, orthe new test and effects in the target spe­
cies.

NIEHS (National Institute of Environmental Health Sciences). 1997. Validation and regulatory acceptance of
toxicological test methods: A report of the ad hoc Interagency Coordinating Committee on the Validation of
Alternative Methods. NIH Publication No. 97-3981. NIEHS, Research Triangle Park, NC.

P-2

Appendix Q

Guidelines and Regulations for Dermal Corrosivity
AGENCY OR
ORGANIZATION
Consumer Product
Safety Commission(CPSC)

Occupational Safety
and HealthAdministration(OSHA)US Department ofTransportation(USDOT)(US DOT)GUIDELINES AND
REGULATIONS1
16CFR1500§1500.3-Definitions§1500.4-Human experience withhazardous substances§1500.41-Method of testing
primary irritant substances
29CFR1917§1917.28 (2) Definition ofCorrosive

The method involves the applicationof the test substance on the hair-freeintact and abraded skin of at least 6
albino rabbits.
OSHA accepts determination ofdermal corrosivity by Corrositex®
and other in vitro tests.

29CFR1910§1910.1200 Hazard
Communication(includes Appendix A)

States that OSHA does not requirechemical manufacturers or importers
to conduct animal tests for theevaluation of the hazard potential ofchemical products.

Exemption allowing use ofCorrositex® as an alternative test
method.

Original exemption granted 28 April
1993. Current exemption expires 30
November 2000.

49CFR 173§173.136(a)(1) Class 8
Definitions§173.137(a), (b), (c)(1) Class 8
Assignment of Packing Group
49CFR172§172.442 Corrosive Label§172.558 Corrosive Placard

US Environmental
Protection Agency(EPA), Office of Solid
Waste and Emergency
Response

COMMENTS

62FR32452 (13 June, 1997)(final rule) affecting 40 CFR Parts
260, 264, 265, and 266.
Hazardous Waste Management
System; Testing and Monitoring
Activities.
Incorporates by reference update
III of "Test Methods for
Evaluating Solid Waste,
Physical/Chemical Methods," EPA
Publication SW-846, 3rd ed. SW­
846 Method 9040
(40CFR261.22) determines
corrosivity by the pH extremes (≤2 or ≥ 11.5).

Q-1§173.137 requires determination of
the packing group based on datafrom tests conducted in accordancewith 1992 OECD Guideline for
Testing of Chemicals, No. 404, Acute
Dermal Irritation/Corrosion.

State-of-the-art analyticaltechnologies for RCRA-related
testing include Method 1120, Dermal
Corrosion, which describes the use of
the Corrositex® test kit.
http://www.epa.gov:80/epaoswer/
hazwaste/test/1120.pdf
http://www.access.gpo.govlsu_docs/
aces/aces140.html

Appendix Q: Guidelines and Regulations for Dermal Corrosivity

AGENCY OR
ORGANIZATIONGUIDELINES AND
REGULATIONSCOMMENTS

EPA, Office of
Pollution Prevention
and Toxic Substances(OPPTS)

OPPTS 870.2500 Acute Dermal
Irritation

EPA Health Effects Test Guidelines
http://www.epa.gov/docs/OPPTS_
Harmonized/870_Health_Effects_
Test_Guidelines/Drafts/

EPA, Office ofPesticides

40CFR152§152.170 Criteria for restriction touse by certified applicators
40CFR156§156.10 Labeling requirements(skin corrosives are assigned
toxicity category I)
40CFR157§157 Subpart B - Child-Resistant
Packaging (§157.22 statesrequirement for pesticides
corrosive to the eyes or skin)

US Food and Drug
Administration(US FDA)

Organization for
Economic Cooperation
and Development(OECD)

40CFR158§158.690 (acute dermal toxicity
testing requirement forbiochemical pesticides is waived if
corrosive to skin or falls within the
corrosive pH ranges)
21CFR 70
§70 Subpart C - Safety
Evaluation. §70.42(b) Criteria forevaluating the safety of color
additives
Harmonized integrated hazard
classification system for humanhealth and environmental effects
of chemical substances.

1

Corrosivity not mentioned per se.
Sensitization and primary irritation
mentioned.
No other formal regulations foundwith respect to corrosivity.
Provides a tiered testing strategy forthe evaluation of dermal corrosivity.
http://www.oecd.org//ehs/class/hclfinaw.doc

Unless otherwise specified in the comments column, guidelines may be accessed via the US
Government Printing Office (GPO) Code of Federal Regulations database
http://www.access.gpo.gov/nara/cfr/cfr-table-search.html.

Q-2

Appendix Q: Guidelines and Regulations for Dermal Corrosivity

Q-3

Appendix Q: Guidelines and Regulations for Dermal Corrosivity

Q-4

Appendix Q: Guidelines and Regulations for Dermal Corrosivity

Q-5

Q-6

Appendix R

R-1

Appendix R: Federal Register Notices

R-2

Appendix S

Corrositex® Peer Review Meeting Agenda
Interagency Coordinating Committee on the
Validation of Alternative Methods (ICCVAM)
and theNational Toxicology Program (NTP) Interagency Center for the
Evaluation of Alternative Toxicological Methods (NICEATM)
January 21, 1999, 8:30 a.m. to 5:30 p.m.
Rooms E1 & E2
William H. Natcher Conference Center
45 Center Drive
Bethesda, MD

8:30 a.m.

Introductions

Dr. Robert Scala

8:40 a.m.

Welcome from the NTP

Dr. George Lucier

8:45 a.m.

Introduction to NICEATM and ICCVAM
Overview of the Corrositex® Peer Review Process

Dr. William Stokes

9:00 a.m.

Summary of Current Agency Requirements

Dr. Richard Hill

9:15 a.m.

Overview of the Proposed Corrositex® Assay

Dr. Rosalind Wei

9:35 a.m.

Questions Regarding the Test Method Protocol

Dr. Rosalind Wei

9:55 a.m.

Peer Review Panel Discussion
Test Method Description

Dr. John Harbell, CoordinatorDrs. Karen Kohrman and John Stegeman

10:30 a.m.

Break

10:50 a.m.

Peer Review Panel Discussion (continued)
Test Method Data Quality
Dr. Sidney Green, CoordinatorDrs. Michael Derelanko, John Harbell
and Hajime Kojima
Test Method Performance

12:45 p.m.

Dr. A. Wallace Hayes, CoordinatorDrs. Karen Kohrman and James Chen

Public Comment

S-1

Appendix S: Corrositex® Peer Review Meeting Agenda

1:05 p.m.

Lunch Break

2:05 p.m.

Peer Review Panel Discussion (continued)
Test Method Reliability
Dr. Julia Fentem, CoordinatorDrs. James Chen and Daniel Sauder
Other Literature and Scientific
Reviews

Dr. Michael Derelanko, Coordinator
Dr. Hajime Kojima

3:00 p.m.

Break

3:20 p.m.

Peer Review Panel Discussion (continued)
Presentation of Corrositex® Performance
Compared to the pH test
Other Considerations andRelated Issues

4:10 p.m.

Final Public Comments

4:30 p.m.

Peer Review Panel Conclusions

5:30 p.m.

Adjourn

Dr. Thomas Goldsworthy

Dr. John Stegeman, Coordinator
Dr. Daniel SauderDrs. Robert Scala and Julia Fentem

S-2

Appendix T

Corrositex® Peer Review Meeting Summary Minutes
January 21, 1999
Bethesda, Maryland•

Introduction••

A public meeting of an independent peer review
panel (PRP) was convened on January 21, 1999,
in Bethesda, Maryland to review Corrositex®,
which was proposed as an alternative toxico­
logical test method for assessing the corrosivity
potential of chemicals and products. The meet­ing was coordinated by the Interagency Coor­
dinating Committee for the Validation of Alter­
native Methods (ICCVAM) and the National
Toxicology Program (NTP) Interagency Cen­
ter for the Evaluation of Alternative Toxicologi­
cal Methods (NICEATM) and was sponsoredby the National Institute of Environmental
Health Sciences (NIEHS) and the NTP.

List of Attendees
•
•
•
•
•
•
•

The following expert scientists served on the
PRP:
•
•
•
•
•
•
•
•

Gamble Company, Cincinnati, Ohio
Hajime Kojima, Ph.D., Nippon Menard
Cosmetic Company, Ltd., Nagoya, Japan
Daniel Sauder, M.D., University of Toronto,
Toronto, Ontario
John Stegeman, Ph.D., Woods Hole
Oceanographic Institution, Woods Hole,
Massachusets••

Robert Scala, Ph.D., retired from Exxon
Biomedical Sciences, Rehoboth Beach,
Delaware (Chair)
Julia Fentem, Ph.D., Unilever Research
Colworth, Bedfordshire, United Kingdom(Executive Secretary)
James Chen, Ph.D., National Center for
Toxicological Research (NCTR), Little
Rock, Arkansas
Michael J. Derelanko, Ph.D., Allied-Signal,
Inc., Morristown, NJ
Sidney Green, Ph.D., Howard University
College of Medicine, Washington, D.C.
John Harbell, Ph.D., Institute for In Vitro
Sciences, Inc. (IIVS, Inc.), Gaithersburg,
MarylandA. Wallace Hayes, Ph.D., the Gillette Com­pany, Boston, Massachusetts
Karen Kohrman, Ph.D., the Procter &

•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
T-1

Susan Aitken, Consumer Product Safety
Commission (CPSC)
Surender Ahir, Occupational Safety and
Health Administration (OSHA)
June Bradlaw, Food and Drug Administra­tion (FDA)
Loretta Brammell, NIEHS/NICEATM
Robert Bronaugh, FDA
Rodger Curren, IIVS, Inc.
George Cushmac, US Department of Trans­
portation (US DOT)
Alan Goldberg, Johns Hopkins University
Thomas Goldsworthy, Integrated Labora­
tory Systems, Inc. (ILS, Inc.)/NICEATM
Ben Gregg, US Environmental Protection
Agency (US EPA)
George Lucier, NIEHS
Karen Haneke, ILS, Inc./NICEATM
Ann Hanger, US EPADavid Hattan, FDA
Patrick Herron, ILS, Inc./NICEATM
Barbara Hill, FDA
Erin Hill, IIVS, Inc.
Richard Hill, US EPA
Vera Hudson, National Library of Medicine(NLM)
Leonard Keifer, US EPAFrancis Kraszewski, Gillette Company
Marianne Lewis, US EPA
Jeanie McAndru, US EPA
Barry Margolin, ILS, Inc./NICEATM
Kathy Miner, ILS, Inc./NICEATM

Appendix T: Corrositex® Peer Review Meeting Summary Minutes

•
•
•
•
•
•
•
•
•
•
•
•
•
•

Hari Mukhoty, US EPA
Thomas Re, Cosmair
John Redden, US EPA
Katherine Stitzel, Procter & Gamble
William Stokes, NIEHS/NICEATM
Raymond Tice, ILS, Inc./NICEATMMark Torreson, National Institute for Oc­
cupational Safety and Health (NIOSH)
Heather Vahdat, ILS, Inc./NICEATM
Kay Valeda, National Heart, Lung andBlood Institute (NHLBI)
Sherry Ward, the Gillette Company
Rosalind Wei, InVitro International, Inc.
(IVI)
Neil Wilcox, FDA
Yung Yang, US EPA
Errol Zeiger, NIEHS

Dr. Stokes explained the ICCVAM review pro­cess, and the steps that had been undertaken in
the review of Corrositex®. He discussed the roleof the ICCVAM committee, its expert subgroup(Corrosivity Working Group [CWG]), the PRP,
and the process by which regulations are re­viewed and forwarded to agencies for action.
Public Law 103-43 directed the NIEHS to de­velop and validate alternative methods that can
reduce or eliminate the use of animals in acuteor chronic toxicity testing, establish criteria forthe validation and regulatory acceptance of al­
ternative testing methods, and recommend a
process through which scientifically validated
alternative methods can be accepted for regula­tory use. Criteria and processes for validation
and regulatory acceptance were developed inconjunction with 13 other Federal agencies andprograms with broad input from the public.
These are described in the document “Valida­tion and Regulatory Acceptance of Toxicologi­
cal Test Methods: A Report of the Ad Hoc In­
teragency Coordinating Committee on the Vali­
dation of Alternative Methods,” NIH Publica­tion 97-3981, March, 1997. This document isavailable in the internet at http://ntpserver.niehs.nih.gov/htdocs/ICCVAM/ICCVAM.htm. ICCVAM was subsequently
established in a collaborative effort by NIEHS
and 13 other Federal regulatory and research
agencies and programs. The Committee’s func­
tions include the coordination of interagency
reviews of toxicological test methods and com­munication with stakeholders throughout theprocess of test method development and vali­
dation. The following Federal regulatory andresearch agencies and organizations are partici­
pating in this effort:

Meeting—Background Information
Introductions
Dr. Scala, Chair, called the meeting to order at
8:30 a.m. and asked each person in attendance
to state their name and affiliation.
Welcome from the NTP
Dr. George Lucier, Director of the NTP, thanked
the ICCVAM participating agencies and stake­holders, the Corrositex® Sponsor, and the PRP
for their efforts. Dr. Lucier also presented an
overview of the NTP and the ICCVAM process.
Introduction to NICEATM and ICCVAM/ Over­view of the Corrositex® Peer Review Process
Dr. William Stokes, ICCVAM Co-Chair andDirector of NICEATM, read the conflict ofinterest statement that had been signed byeach member before agreeing to serve on the
PRP. Dr. Stokes asked if any PRP members
had a change in their conflict of interest
status; none were raised.

•
•
•
•

T-2

Consumer Product Safety Commission
Department of Defense
Department of Energy
Department of Health and Human Services

Appendix T: Corrositex® Peer Review Meeting Summary Minutes

•

•
•
•
•
•

skin. Dr. Hill further stated that testing is usu­
ally done using the in vivo rabbit skin corrosivity
test. The test results serve as a basis for deter­mining appropriate materials labeling and haz­ard identification. An international harmoniza­tion effort has been in progress in order to de­velop internationally consistent labeling. Mea­
surement of pH is used to define potential cor­rosives, where chemicals which have a pH in
the extreme ranges are considered to be poten­
tial corrosives for labeling purposes. Currently,
the US DOT has accepted Corrositex® as amethod to determine the corrosive potential ofseven chemical classes. Dr. Hill also mentionedthat a tiered testing scheme has been proposed
by OECD for determining dermal corrosivity
potential of chemicals/products.

Agency for Toxic Substances and Dis­ease Registry• Food and Drug Administration• National Institutes of Health• National Cancer Institute• National Institute of Environmental
Health Sciences• National Library of Medicine
National Institute for Occupational Safety
and Health/CDC
Department of the Interior
Department of Labor• Occupational Safety and Health Admin­
istration
Department of Transportation• Research and Special Programs Admin­
istration
Environmental Protection Agency

Overview of the Corrositex®
®

Corrositex was proposed to ICCVAM for con­sideration as an in vitro method for use in de­termining the dermal corrosivity potential ofchemicals. The test method submission was
prepared by IVI. Independent peer review isan essential prerequisite for consideration of amethod for regulatory acceptance (NIEHS,
1997). The PRP was charged with developinga scientific consensus on the usefulness of themethod to generate information for humanhealth risk assessment purposes. The proposed
test method and results of the peer review will
be forwarded by ICCVAM to Federal agencies
for consideration. Federal agencies will deter­mine the regulatory acceptability of the method
according to their mandates.

Dr. Rosalind Wei, Director of Research andDevelopment at IVI, described the procedureused to test chemicals or compounds using
Corrositex®. The presentation was followed byassay-related questions from the PRP.
Meeting—Review of the Corrositex®
Submission
Test Method Description
Dr. Harbell, the section coordinator, presented
the analysis and conclusions reached by the test
method description section reviewers, which
included Drs. Kohrman and Stegeman.

Summary of Current Agency Requirements

The PRP concluded that the basis for the test
was adequately described, and the protocol wascomplete and consistent. They further con­cluded that the decision rules were adequately
defined, and that the range of applications is
known to some degree.

Dr. Richard Hill, ICCVAM and CWG Co-Chair,presented an overview of current agency regu­
lations with regard to dermal corrosion testing.
He stated that corrosion is not universally de­fined, but generally focuses on destruction of
the skin or the irreversability of effects on the

T-3

Appendix T: Corrositex® Peer Review Meeting Summary Minutes

Test Method Data Quality

Test Method Reliability

Dr. Green, the section coordinator, presented theanalysis and conclusions reached by the test
method data quality section reviewers, which
included Drs. Derelanko, Harbell, and Kojima.

Dr. Fentem, the section coordinator, presented
the analysis and conclusions reached by the test
method reliability section reviewers, which in­cluded Drs. Chen and Sauder.

With regard to data quality, the PRP concluded
that the studies presented in the Submission
were not conducted under Good Laboratory
Practice (GLP) standards, but that the data werecredible, based on results from two data audits.
Studies conducted as part of the European Cen­tre for the Validation of Alternative Methods(ECVAM) prevalidation and validation studies
were conducted under the “spirit” of GLP.

The PRP concluded that the reproducibility ofthe test was adequate, although one peer re­viewer felt that additional interlaboratory inves­tigations would be helpful. The PRP suggested
the inclusion of positive and negative controls
and analysis of variance in future intra- andinter-laboratory evaluations.

Test Method Performance

Dr. Derelanko, the section coordinator, pre­sented the analysis and conclusions reached by
the other literature and scientific reviews sec­tion reviewers, which included Dr. Kojima.

Other Literature and Scientific Reviews

Dr. Hayes, the section coordinator, presented theanalysis and conclusions reached by the test
method performance section reviewers, which
included Drs. Kohrman and Chen.

Key papers evaluated are listed below:• Barratt, M. D., P. G. Brantom, J. H. Fentem,

The PRP concluded that certain limitations were
present in the data set (i.e., complex mixtures
were not defined and thus could not be evalu­
ated; category definitions were vague, so some
could not be considered in the evaluation; andthe number of chemicals in some chemicalclasses was limited such that performance analy­
sis for these classes may not be representative).
However, the PRP concluded that the accuracy(82%), sensitivity (85%), specificity (70%), andpositive and negative predictivity (78% and80%, respectively) were adequate for the data
set including the Submission, Prevalidation
Study (Botham et al., 1995), and ECVAM Vali­
dation Study (Fentem et al., 1998). The PRP
felt that the assay was useful as a stand-alone
method for predicting the corrosive potential ofacids and bases. The test can also be used aspart of a tier assessment approach for determin­
ing the dermal corrosion potential of substancesin other chemical classes.

•

•

T-4

I. Gerner, A. P. Walker, and A. P. Worth.
1998. The ECVAM international validation
study for in vitro tests for skin corrosivity.
1. Selection and distribution of the test
chemicals. Toxicol. In Vitro 12:471-482.
Botham, P. A., M. Chamberlain, M. D.
Barratt, R. D. Curren, D. J. Esdaile, J. R.
Gardner, V. C. Gordon, B. Hildebrand, R.
W. Lewis, M. Liebsch, P. Logemann, R.
Osborne, M. Ponec, J.-F. Régnier, W.
Steiling, A. P. Walker, and M. Balls. 1995.
A prevalidation study on in vitro skincorrosivity testing: The report and recom­
mendations of ECVAM Workshop 6. ATLA
23:219-255.
Fentem, J. H., G. E. B. Archer, M. Balls, P.
A. Botham, R. D. Curren, L. K. Earl, D. J.
Esdaile, H.-G. Holzhütter, and M. Liebsch.
1998. The ECVAM international validation
study on in vitro tests for skin corrosivity.

Appendix T: Corrositex® Peer Review Meeting Summary Minutes•

tween pH and Corrositex ® in identifying
corrosivity.

2. Results and evaluation by the manage­
ment team. Toxicol. In Vitro 12:483-524.
Gordon, V. C., J. D. Harvell, and H. I.
Maibach. 1994. Dermal corrosion, theCorrositex system: A DOT accepted method
to predict corrosivity potential of test mate­rials. Alternative Methods Toxicol. 10:37­
45.

Summary of Nonqualifying Chemicals
Ms. Karen Haneke, NICEATM, presented an
overview of available data on nonqualifying
chemicals, focusing on nonqualifying test ma­
terials for which there was also pH and in vivo
data. Of the 75 nonqualifying test materials
identified in published sources and a 1996
Corrositex® submission, 85% of these materi­als were considered noncorrosive according toin vivo test results. pH data were found for 50
nonqualifying materials, of which all but one
were in the pH range of 3 to 10. pH distribu­
tion was similar when the database of
nonqualifiers was limited to only test materials
for which both pH and in vivo data was avail­able (N = 33); when this limited data set wasevaluated, 91% of the chemicals were noncor­
rosive according to in vivo tests.

The PRP concluded that generally, the results
reported in these papers were similar to thosepresented in the Submission. It was noted that
the Gordon et al. (1994) publication was not peer
reviewed.
Presentation of Corrositex® Performance Com­
pared to the pH Test
Dr. Thomas Goldsworthy, NICEATM, pre­sented the findings of an evaluation of the per­formance of pH compared to that of Corrositex®;
both tests were compared against in vivo rabbit
skin corrosivity data as the standard. The analy­
sis found that both the pH test and Corrositex®
are adequate for identifying the corrosive po­tential of chemicals with a pH value in the ex­treme ranges (i.e., pH less than or equal to 2 orgreater than or equal to 11.5). However,Corrositex® was slightly but consistently morepredictive than pH for chemicals with a pH
value in the extreme ranges. Further,
Corrositex® correctly identified several non­corrosive chemicals with pH values in the ex­treme ranges; these chemicals would be false
positive calls if analyzed only by pH. Addi­
tionally, a number of chemicals with pH values
in the non-extreme range (i.e., pH greater than
2 and less than 11.5) were identified as corro­
sive using the in vivo test; Corrositex® correctly
identified the majority of these compounds.
Given the ease and cost effectiveness of con­ducting a pH test, the PRP recommended that
pH testing be conducted prior to the use ofCorrositex®. Such information could be usedin the future to re-evaluate the agreement be­

Other Considerations and Related Issues
Dr. Stegeman, the section coordinator, presented
the analysis and conclusions reached by theother considerations and related issues section
reviewers, which included Dr. Sauder.
The PRP noted several advantages of theCorrositex® test compared to the in vivo rabbit
skin corrosivity test. Corrositex® is a non-ani­
mal test that is also relatively quick and easy to
perform. The PRP stated that the large propor­
tion of test materials that do not qualify for test­
ing by the Corrositex® method is one limitationof the assay.
The PRP also agreed that the assay, whether usedalone or as a component of a tiered assessment
approach, provides for the reduction and re­placement of animal use for certain definedchemical classes. Additionally, chemicals thattest negative or do not qualify for Corrositex®
T-5Appendix T: Corrositex® Peer Review Meeting Summary Minutes

have a low likelihood of causing corrosive le­sions if tested in animals. Any follow-up tests
using in vivo methods could employ small num­bers of animals and test agent dilution schemes
to minimize numbers of animals and possible
distress in any individual animal.

Kohrman stated that the variability probably
deals with small sample size. Dr. Goldsworthy
added that evaluations were done on a wide
variety of sources and combinations thereof, andgenerally, the data sets were found to be similar
to each other.

Public Comments

Dr. Katherine Stitzel, Procter & Gamble, feltthat the PRP should give additional thought tothe statement that 20 chemicals per class would
be an adequate number for evaluation. She
stated that this may be setting a precedent that
may be difficult to meet, strictly based on theprevalence of some chemical classes. She fur­ther added that making such a statement may
be setting a standard for the in vitro test thatwas not set for the in vivo test.

Dr. Rodger Curren, IIVS, Inc., stated that since
this is only the second ICCVAM review, thereview is a precedent-setting activity. The PRP
must determine whether the use of Corrositex®
would provide an equivalent level of protection
compared to the currently accepted in vivo rab­
bit skin corrosivity test. Dr. Curren added thatwith regard to reproducibility, he felt that datafrom only a few labs was adequate because there
are performance standards (i.e., positive andnegative controls). To address a PRP discus­
sion on the adequacy of evaluatinginterlaboratory data from only three labs, with
one being naïve, Dr. Curren stated that none of
the labs were naïve; they all had experience in
conducting the test. In response to the PRP’scomment that the number of chemicals for someclasses was inadequate for performance assess­ment purposes, he mentioned the difficulty inobtaining adequate in vivo data for comparison.

Dr. Errol Zeiger, NIEHS, made additional com­ment on the issue of prevalence and how many
chemicals are needed for an adequate evaluated.
He pointed out that when speaking of preva­
lence, the discussion is not the prevalence ofchemicals classes in the universe, but rather theprevalence of chemical classes in specific in­dustries. Dr. Zeiger noted that the prevalenceof certain chemical classes thus changes basedon the industry evaluated and the endpoint ofinterest. Dr. Zeiger also provided comment on
the issue of the interlaboratory reliability study
and how dependent and nonindependent labs
play a role in these types of assessments. He
stated that one method of assessment is to in­clude only labs with experience in conducting
the assay, while a second is to include only labs
with limited experience with the assay. Dr.
Zeiger felt that the equivalence of training
among the three labs is an asset to the evalua­tion, and urged caution in evaluating how labs
are determined to be dependent versus indepen­dent.

Dr. Alan Goldberg, Johns Hopkins University,
asked two questions to members of the PRP.
First, he asked for clarification on the statementthat auditors concluded that the discrepancies
did not affect the conclusions reached from thedata. Dr. Green responded that the data defi­
ciencies and missing data were very few, andwere thus determined to have minimal effect.
Second, Dr. Goldberg noted that one of the data
sources evaluated (submissions and publishedsources) was slightly different in performancecompared to the others, and asked how thatwould affect the totality of the data. Dr.

T-6

Appendix T: Corrositex® Peer Review Meeting Summary Minutes

Dr. Francis Kraszewski, the Gillette Company,
asked if the PRP was satisfied with the mecha­
nistic basis of the assay. Dr. Hayes clarified
that the test is not mechanistically based, butinstead is significantly correlated.

Dr. Robert Bronaugh, FDA, asked for clarifica­tion from the PRP about the database, andwhether it is considered adequate versus inad­
equate. Dr. Scala answered that the database isconsidered to be adequate, but that data for cer­tain chemical classes may be inadequate due tothe few numbers of chemicals in those classes.

Dr. David Hattan, FDA, asked, from a regula­tory standpoint, whether the PRP felt that theresults on neat materials could be translated toreflect the response of final formulations. Dr.
Kohrman replied that the answer was depen­
dent on what is known about the matrix. She
stated that with proper information, it is pos­sible to make an assessment of the entire mix­
ture based on results found using neat materi­als. Dr. Sauder added that the question is very
valid, and that information/studies pertinent to
the topic would be helpful.

PRP Conclusions
Based on their review, the PRP concluded that
the Corrositex® method is equivalent to the invivo rabbit skin corrosivity test for predicting
corrosivity and noncorrosivity for specified
chemical classes (i.e., primarily acids andbases). Therefore the test may be used either asa stand-alone assay for determining the dermal
corrosion potential of acids or bases or as partof a tier assessment approach for determining
the dermal corrosion potential of substances inother chemical classes.

Dr. Ben Gregg, US EPA, stated that most mate­rials reviewed by his agency are mixtures, andthat US EPA may be interested in using
Corrositex® as a replacement for in vivo testingof mixtures. He stated that more work should
be directed toward how the test performs for
mixtures.

The meeting was adjourned.

T-7

Appendix U

Summary of Public Comments on Corrositex®
Two Federal Register Notices were publishedon July 28, 1998 (Vol. 63, No. 144) and Octo­
ber 27, 1998 (Vol. 63, No. 207) respectively,
requesting public comments on the Corrositex®
test method. Information was also included re­garding the availability of a public test method
document located at the Consumer Product
Safety Commission (CPSC) Reading Room.
Responses were received from three individu­
als as listed below:
Karen E. Purves (September 11, 1998) Animal
Protection Institute
Ms. Purves’ comments focused on validation
and regulatory acceptance criteria as listed in
the Interagency Coordinating Committee on the
Validation of Alternative Methods (ICCVAM)
document “Validation and Regulatory Accep­
tance of Toxicological Methods” (NIH Pub No.
97-3981). The following points summarize Ms.
Purves’ comments:•

Corrositex® can be used to properly deter­mine corrosivity for US Department ofTransportation (US DOT) shipping classi­
fications quickly and at a reduced cost•

Detailed protocol for test method is readily
available from InVitro International (IVI).

•

Reproducibility and reliability have been
demonstrated both in tests performed by IVI
and in pre-validation studies conductedunder European Centre for the Validationof Alternative Methods (ECVAM).

•

Adequate data is available from in vivo andpH studies to allow for comparisions withCorrositex®.

•

Procedural information for the performanceand determination of results is provided forCorrositex®.

•

There is a 93% correlation between
Corrositex® and in vivo responses.

•

Corrositex® provides data that allows forclassification, labeling, and packaging of
hazardous materials making it useful for risk
assessment.

•

Corrositex® is less expensive as well as timeeffective when compared to animal testing
and more accurate when compared to pH
testing.

•

Corrositex® provides a replacement alterna­
tive to animal use in corrosivity testing.

Linda Sternberg (October 30, 1998)
BetzDearborn, Inc.
Ms. Sternberg stated that while she recognizes
that Corrositex® may be expedient and cost-ef­
fective in some circumstances, the assay did notappear to perform satisfactorily for the
BetzDearborn product lines. BetzDearborn pro­vides “engineered chemical treatments for in­fluent water, boiler, cooling systems, wastewa­
ter and process systems” and most of the prod­
ucts tested using Corroistex® were mixtures.
Experiments were performed on 74 of thecompany’s products using Corrositex® (11 ofwhich did not qualify for use). A 65% (41/63)
error rate was observed among the qualifying
products with a lack of agreement between datafrom Corrositex® and animal data and/or sup­plier information. Ms. Sternberg concedes thattheoretically, a ‘correlation factor’ could be gen­U-1

Appendix U: Summary of Public Comments on Corrositex®

erated to compensate for these differences but
points out that the money and time required to
do so would contradict BetzDearborn’s purposein using Corrositex®.

evaluating interlaboratory data from only threelabs, with one being naïve, Dr. Curren statedthat none of the labs were naïve; they all had
experience in conducting the test. In responseto the PRP’s comment that the number of chemi­cals for some classes was inadequate for per­formance assessment purposes, he mentioned
the difficulty in obtaining adequate in vivo datafor comparison.

Tom Hearty (January 18, 1999) Mallinckrodt,
Inc.
Mallinckrodt tested two of their products using
both Corrositex® and the in vivo corrosivity test
outlined in OECD Guideline 404. One product(pH 12.7) was identified by both in vivo andCorrositex® test results as a noncorrosive sub­stance. Corrositex® test results identified thisproduct as a Category II material with a mean
breakthrough time of greater than 70 minutes.
The second product (pH 13.2) was found to benoncorrosive using the in vivo test, but was iden­tified as corrosive by Corrositex®. The productwas assigned to Packing Group III byCorrositex® since the product was a Category
II material and had a mean breakthrough timeof 47 minutes. The in vivo test results indicatedthat this compound was a moderate to severe
irritant. Based on this result, Mr. Hearty feltthat Corrositex® is too sensitive in its responses.

Dr. Alan Goldberg, Johns Hopkins University,
asked two questions to members of the PRP.
First, he asked for clarification on the statementthat auditors concluded that the discrepancies
did not affect the conclusions reached from thedata. Dr. Green responded that the data defi­
ciencies and missing data were very few, andwere thus determined to have minimal effect.
Second, Dr. Goldberg noted that one of the data
sources evaluated (submissions and publishedsources) was slightly different in performancecompared to the others, and asked how thatwould affect the totality of the data. Dr.
Kohrman stated that the variability probably
deals with small sample size. Dr. Goldsworthy
added that evaluations were done on a wide
variety of sources and combinations thereof, andgenerally, the data sets were found to be similar
to each other.

Additional Public Comment
The following public comments were presented
during the public comment period at the Janu­ary 21, 1999 peer review panel (PRP) meeting:

Dr. Katherine Stitzel, Procter & Gamble, feltthat the PRP should give additional thought tothe statement that 20 chemicals per class would
be an adequate number for evaluation. She
stated that this may be setting a precedent that
may be difficult to meet, strictly based on theprevalence of some chemical classes. She fur­ther added that making such a statement may
be setting a standard for the in vitro test thatwas not set for the in vivo test.

Dr. Rodger Curren, Institute for In Vitro Sci­
ences, stated that since this is only the second
ICCVAM review, the review is a precedent-set­ting activity. The PRP must determine whether
the use of Corrositex® would provide an equiva­
lent level of protection compared to the currently
accepted in vivo rabbit skin corrosivity test. Dr.
Curren added that with regard to reproducibil­
ity, he felt that data from only a few labs wasadequate because there are performance stan­dards (i.e., positive and negative controls). To
address a PRP discussion on the adequacy of

Dr. Errol Zeiger, National Institute of Environ­mental Health Sciences (NIEHS), made addi­
tional comment on the issue of prevalence andhow many chemicals are needed for an adequate
U-2

Appendix U: Summary of Public Comments on Corrositex®

whether the PRP felt that the results on neatmaterials could be translated to reflect the re­sponse of final formulations. Dr. Kohrman re­plied that the answer was dependent on what is
known about the matrix. She stated that withproper information, it is possible to make anassessment of the entire mixture based on re­sults found using neat materials. Dr. Sauderadded that the question is very valid, and that
information/studies pertinent to the topic would
be helpful.

evaluation. He pointed out that when speakingof prevalence, the discussion is not the preva­
lence of chemicals classes in the universe, butrather the prevalence of chemical classes in spe­cific industries. Dr. Zeiger noted that the preva­
lence of certain chemical classes thus changes
based on the industry evaluated and the end­
point of interest. Dr. Zeiger also provided com­ment on the issue of the interlaboratory reliabil­
ity study and how dependent andnonindependent labs play a role in these typesof assessments. He stated that one method ofassessment is to include only labs with experi­ence in conducting the assay, while a second is
to include only labs with limited experience withthe assay. Dr. Zeiger felt that the equivalenceof training among the three labs is an asset tothe evaluation, and urged caution in evaluating
how labs are determined to be dependent ver­sus independent.

Dr. Ben Gregg, US Environmental Protection
Agency (US EPA), stated that most materials
reviewed by his agency are mixtures, and that
US EPA may be interested in using Corrositex®
as a replacement for in vivo testing of mixtures.
He stated that more work should be directed to­ward how the test performs for mixtures.
Dr. Robert Bronaugh, FDA, asked for clarifica­tion from the PRP about the database, andwhether it is considered adequate versus inad­
equate. Dr. Scala answered that the database isconsidered to be adequate, but that data for cer­tain chemical classes may be inadequate due tothe few numbers of chemicals in those classes.

Dr. Francis Kraszewski, the Gillette Company,
asked if the PRP was satisfied with the mecha­
nistic basis of the assay. Dr. Hayes clarified
that the test is not mechanistically based, butinstead is significantly correlated.
Dr. David Hattan, Food and Drug Administra­tion (FDA), asked, from a regulatory standpoint,

U-3

Appendix V

D EPART MENT OF HEA LTH AND HUMAN SERVICES

N ational Institut es of HealthN ational Institut e of
Env ironmental Health Sciences
P. O. Box 12233
R esearc h Triangle Park , NC 27709

Date:

June 4, 1999

From:

Co-Chairs, Interagency Coordinating Committee on the Validation of
Alternative Methods (ICCVAM)

Subject:

Peer review report on Corrositex®; Request to forward to agencies forregulatory and non-regulatory acceptance considerationTo:

Director, National Toxicology Program (NTP)

Thru:

Director, Environmental Toxicology Program,
National Institute of Environmental Health Sciences __________We are pleased to provide you with the peer review report, Corrositex®: A Test Method for Assess­ing the Dermal Corrosivity Potential of Chemicals (Attachment 1) which was reviewed and ap­
proved by ICCVAM at its May 22, 1999 meeting. The review of Corrositex® was coordinated by
ICCVAM and the NTP Interagency Center for the Evaluation of Alternative Toxicological Meth­ods (NICEATM). Corrositex® is the first in vitro method and the second test method to undergo
evaluation by the ICCVAM on behalf of its 14 participating Federal agencies and programs.
ICCVAM concurred with the conclusions and recommendations of the Peer Review Panel (PRP)
and the ICCVAM Corrosivity Working Group (CWG) (Attachment 2) regarding the potential use­
fulness of Corrositex®. The PRP concluded that Corrositex® may be used as part of a tiered testing
strategy for assessing the dermal corrosion potential of chemicals, such as the one endorsed by theOrganization for Economic Cooperation and Development (OECD). The OECD tiered testing
strategy for dermal irritation/corrosivity provides for the use of validated and accepted in vitro
methods. In this approach, positive responses do not generally require further testing, while nega­tive responses would usually be followed by in vivo dermal irritation/corrosion testing. The PRP
recommended that with either positive or negative Corrositex® results, there should be the oppor­
tunity for confirmatory testing if false positive or negative results are suspected based on a weight­of-evidence evaluation of supplemental information, such as pH, structure-activity relationships(SAR), and other chemical and testing information. ICCVAM concurs with the PRP that Corrositex®,in specific testing circumstances, may be useful as an assay for evaluating the corrosivity or
noncorrosivity of acids, bases, and acid derivatives (e.g., US Department of Transportation [USDOT]).
The PRP concluded that the use of Corrositex® offers several advantages with respect to animal
welfare. Corrositex®, when used as a stand-alone assay for some testing applications such as

V-4

Appendix V: ICCVAM Request for Regulatory and Non-regulatory
Acceptance Consideration of Corrositex®

transportation purposes, can replace the use of animals for corrosivity testing of qualified chemi­cals in some chemical classes. When used as part of a tiered testing strategy for corrosivity, there
is a reduction in the number of animals required because positive results usually eliminate theneed for animal testing, and when further testing in animals is determined to be necessary, only
one animal is required to confirm a corrosive chemical. Corrositex® also provides for refinementin that most of the chemicals that are identified as negative by Corrositex® or nonqualifying in thedetection system are unlikely to be corrosive when tested in the in vivo test. If any skin lesions areproduced in test animals, they are usually limited to some degree of irritation.
Independent scientific peer review, considered a prerequisite for regulatory acceptance, has now
been completed for Corrositex®. The final stage in the regulatory process involves determinationof the acceptability of Corrositex® by regulatory agencies, and informing the appropriate regulated
community and others of the acceptability of the method for meeting regulatory requirements.
We therefore ask that you forward the attached report to the participating ICCVAM agencies re­questing their consideration of Corrositex® for regulatory acceptance or other non-regulatory appli­
cations where appropriate.
Thank you for your continuing support of ICCVAM and NICEATM’s efforts to achieve validation
acceptance of new methods that will provide for improved protection of human health and theenvironment, and improved animal welfare.

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Appendix V: ICCVAM Request for Regulatory and Non-regulatory
Acceptance Consideration of Corrositex®

D EPART MENT OF HEA LTH AND HUMAN SERVICES

N ational Institut es of HealthN ational Institut e of
Env ironmental Health Sciences
P. O. Box 12233
R esearc h Triangle Park , NC 27709

MEMORANDUM
Date:

May 3, 1999To:ICCVAM

From:

Co-chairs, ICCVAM CWG

Subject:

ICCVAM CWG Recommendations on Corrositex® as a Test Method for Assessing
Dermal Corrosivity Potential of Chemicals

The purpose of this memorandum is to inform ICCVAM that the CWG unanimously endorses
the conclusions and recommendations stated in the PRP Report entitled Corrositex®: An in vitro
test method for assessing the dermal corrosivity potential of chemicals—Results of an indepen­
dent peer review evaluation coordinated by ICCVAM and NICEATM (Attachment 1). The
Report consists of the PRP’s written deliberations and conclusions from the public peer review
meeting convened in Bethesda, Maryland on January 21, 1999. The PRP concurred in a public
meeting via teleconference on April 22, 1999 that the Report accurately reflects the conclusions
and recommendations of the January 21 meeting. Appendices to the Report include data andinformation submitted to substantiate the validation status of the method, and supporting analy­
ses and information prepared by NICEATM. The CWG recommends that ICCVAM forward theCorrositex® Report to applicable Federal and international organizations for regulatory accep­
tance consideration for the uses recommended by the PRP.
The CWG concurs with the PRP’s conclusion that Corrositex® may be used as part of a tiered
testing strategy for assessing dermal corrosion potential of chemicals, such as the one endorsedby the OECD (Attachment 2). The OECD tiered testing strategy for dermal irritation/corrosivity
provides for the use of validated and accepted in vitro methods. In this approach, positive re­sponses do not generally require further testing, while negative responses would usually befollowed by in vivo dermal irritation/corrosion testing. The PRP recommended that with either
positive or negative Corrositex® results, there should be the opportunity for confirmatory testing
if false positive or negative results are suspected based on a weight-of-evidence evaluation of
supplemental information, such as pH, SAR, and other chemical and testing information. The
CWG concurs with the PRP that Corrositex®, in specific testing circumstances, may be useful as
an assay for evaluating the corrosivity or noncorrosivity of acids, bases, and acid derivatives(e.g., US DOT).

V-6

Appendix V: ICCVAM Request for Regulatory and Non-regulatory
Acceptance Consideration of Corrositex®

The PRP concluded that Corrositex® demonstrated excellent intra- and inter-laboratory reproduc­
ibility. The ease of transferability among laboratories and the simplicity of the assay wereconsidered by the PRP to be attractive features of Corrositex®. The manufacturer’s protocol for
Corrositex® was considered to be complete and to provide the necessary details for users to
conduct the assay correctly. Methods for data analysis and decision criteria were considered to
be straightforward, and the PRP noted that concurrent positive and negative controls are included
to determine whether each test trial is performing correctly. The PRP concluded that the test ismore rapid and less expensive than the in vivo rabbit corrosivity test. Since it is an in vitro
alternative test, it also has the advantage that it does not require the use of animals and can be
conducted in laboratories without animal facilities.
Animal Welfare Considerations
The PRP concluded that the use of Corrositex® offers several advantages with respect to animal
welfare. When used as a stand-alone assay for some testing applications such as determining
transportation packing groups, Corrositex® can replace the use of animals for corrosivity testingof qualified chemicals in some chemical classes. When used as part of a tiered testing strategy
for corrosivity, there is a reduction in the number of animals required because positive results
usually eliminate the need for animal testing, and when further testing in animals is determined
to be necessary, only one animal is required to confirm a corrosive chemical. Corrositex® also
provides for refinement in that most of the chemicals that are identified as negative by
Corrositex® or nonqualifying in the detection system are unlikely to be corrosive when tested in
the in vivo test. If any skin lesions are produced in test animals, they are usually limited to somedegree of irritation.
Limitations
A limitation noted by the PRP was that some corrosive chemicals and mixtures do not qualify fortesting with Corrositex®. That is, they do not cause a color change in the Chemical Detection
System (CDS). A color change is needed to enable the detection of the chemical or mixture if it
breaks through the biobarrier membrane, and requires that the chemical change the pH of thesolution to less than 5 or greater than 8.5. Many noncorrosive chemicals do not cause the re­quired change in pH, and thus do not qualify for evaluation by Corrositex®. Of the 75
nonqualifying chemicals and mixtures for which in vivo corrosivity data were available, 85%(64/75) were classified as noncorrosive in the in vivo test. This indicates that nonqualifying
chemicals are often noncorrosive.
Comparative Corrositex® and in vivo rabbit data were provided for complex mixtures that gener­
ally consisted of industrial chemicals, cleaners, detergents, and surfactants. While the perfor­
mance data for Corrositex® are promising for some of these mixtures, the PRP did not consider it
appropriate to reach conclusions for these classes in the assessment of the validation of themethod because the composition of these materials was not provided. Based on the performanceof Corrositex® for mixtures, the CWG thinks that Corrositex® can yield useful information for
those materials that qualify for the test.
The evaluation of Corrositex® for some chemical/product classes was limited by the relatively
small number of chemicals and/or the unbalanced distribution of corrosive and noncorrosive
V-7

Appendix V: ICCVAM Request for Regulatory and Non-regulatory
Acceptance Consideration of Corrositex®

chemicals/mixtures evaluated. As a consequence, conclusions about the performance ofCorrositex® for some chemical classes were not made by the PRP.
CWG recommendations
The CWG concurs with the PRP’s recommendations, and agrees that the following specificchanges to the protocol should be made (Note: The wording for these recommendations has
been slightly revised from those provided in the Report, but it does not change their intent):• Specific information should be added to the protocol:(1)
It should be explicitly stated that the biobarrier should be allowed to harden on a levelsurface and should be refrigerated at 2 to 8 °C overnight before use.
(2)
Even though replicate variability has been shown to be very low, guidance should be pro­vided on how to evaluate an aberrant value.
(3)
The IVI Corrositex® Data Sheets provided with the test kit should include a provision forrecording the performance of the positive and negative controls. This information should
be used to determine the suitability of the test results.
(4)
Description of the test protocol would benefit from the addition of a flow diagram illustrat­
ing the steps in the procedure.
•

In future studies, compliance with Good Laboratory Practice (GLP) Guidelines and inclusionof quality control procedures, would improve data quality and credibility.

•

Positive and negative control values should be reported concurrently with each assay to demon­
strate that the test is working properly.

•

Laboratories unfamiliar with conducting the test should obtain appropriate training and con­duct tests with reference chemicals before undertaking any testing of unknown chemicals andchemical mixtures.

•

pH testing should be conducted prior to use of Corrositex®. Such information could be usedin the future to re-evaluate the agreement between pH and Corrositex® in identifying
corrosivity.

V-8