INTERNATIONAL CONFERENCE ON HARMONISATION OF TECHNICALREQUIREMENTS FOR REGISTRATION OF PHARMACEUTICALS FOR HUMAN
USE

ICH HARMONISED TRIPARTITE GUIDELINE

IMPURITIES IN NEW DRUG PRODUCTS
Q3B(R2)Current Step 4 version
dated 2 June 2006

This Guideline has been developed by the appropriate ICH Expert Working Groupand has been subject to consultation by the regulatory parties, in accordance with the
ICH Process. At Step 4 of the Process the final draft is recommended for adoption to
the regulatory bodies of the European Union, Japan and USA.

Q3B(R2)
Document History
First
Codification

History

Date

New
Codification
November
2005

Q3B

Approval by the Steering Committee under Step 2 andrelease for public consultation.

29
November
1995

Q3B

Q3B

Approval by the Steering Committee under Step 4 andrecommendation for adoption to the three ICH regulatory
bodies.

6
November
1996

Q3B

Q3B(R)

Approval by the Steering Committee of the first Revision
under Step 2 and release for public consultation.

7
October1999

Q3B(R1)Q3B(R)

Approval by the Steering Committee of the first Revision
under Step 4 and recommendation for adoption to the three
ICH regulatory bodies.

5
February
2003

Q3B(R1)2 June2006

Q3B(R2)Current Step 4 version
Q3B(R2)

Approval by the Steering Committee of the revision of the
Attachment 2 directly under Step 4 without further public
consultation.

IMPURITIES IN NEW DRUG PRODUCTS
ICH Harmonised Tripartite Guideline
Having reached Step 4 of the ICH Process at the ICH Steering Committee meetingon 5 February 2003, this guideline is recommended for
adoption to the three regulatory parties to ICH
Attachment 2 has been revised on 6 June 2006.

TABLE OF CONTENTS
1.

INTRODUCTION ........................................................................................ 1

1.1

Objective of the guideline ........................................................................................ 1

1.2

Background .............................................................................................................. 1

1.3

Scope of the guideline .............................................................................................. 1

2.

RATIONALE FOR THE REPORTING AND CONTROL OF
DEGRADATION PRODUCTS ................................................................... 1

3.

ANALYTICAL PROCEDURES.................................................................. 2

4.

REPORTING DEGRADATION PRODUCTS CONTENT OF
BATCHES ..................................................................................................... 2

5.

LISTING OF DEGRADATION PRODUCTS IN SPECIFICATIONS .. 3

6.

QUALIFICATION OF DEGRADATION PRODUCTS ........................... 4

7.

GLOSSARY ................................................................................................... 6

Attachment 1: Thresholds for Degradation Products in New Drug Products .................... 7
Attachment 2: Illustration of Reporting Degradation Product Results for Identification
and Qualification in an Application ..................................................................................... 9
Attachment 3: Decision Tree for Identification and Qualification of a Degradation
Product ................................................................................................................................ 11i

IMPURITIES IN NEW DRUG PRODUCTS
1.

INTRODUCTION

1.1
Objective of the guideline
This document provides guidance for registration applications on the content andqualification of impurities in new drug products produced from chemicallysynthesised new drug substances not previously registered in a region or member
state.
1.2
Background
This guideline is complementary to the ICH Q3A(R) guideline “Impurities in New
Drug Substances”, which should be consulted for basic principles. The ICH Q3C
guideline “Residual Solvents” should also be consulted, if appropriate.
1.3
Scope of the guideline
This guideline addresses only those impurities in new drug products classified asdegradation products of the drug substance or reaction products of the drug substancewith an excipient and/or immediate container closure system (collectively referred toas “degradation products” in this guideline). Generally, impurities present in the new
drug substance need not be monitored or specified in the new drug product unlessthey are also degradation products (see ICH Q6A guideline on specifications).
Impurities arising from excipients present in the new drug product or extracted orleached from the container closure system are not covered by this guideline. This
guideline also does not apply to new drug products used during the clinical research
stages of development. The following types of products are not covered in thisguideline:
biological/biotechnologicalproducts,
peptides,oligonucleotides,
radiopharmaceuticals, fermentation products and semi-synthetic products derived
therefrom, herbal products, and crude products of animal or plant origin. Also
excluded from this document are: (1) extraneous contaminants that should not occur
in new drug products and are more appropriately addressed as good manufacturing
practice (GMP) issues, (2) polymorphic forms, and (3) enantiomeric impurities.
2.

RATIONALE FOR THE
REPORTING AND CONTROL OF
DEGRADATION PRODUCTS
The applicant should summarise the degradation products observed during
manufacture and/or stability studies of the new drug product. This summary should
be based on sound scientific appraisal of potential degradation pathways in the new
drug product and impurities arising from the interaction with excipients and/or theimmediate container closure system. In addition, the applicant should summarise anylaboratory studies conducted to detect degradation products in the new drug product.
This summary should also include test results of batches manufactured during thedevelopment process and batches representative of the proposed commercial process.
A rationale should be provided for exclusion of those impurities that are notdegradation products (e.g., process impurities from the drug substance and impurities
arising from excipients). The impurity profiles of the batches representative of the
proposed commercial process should be compared with the profiles of batches used indevelopment and any differences discussed.
Any degradation product observed in stability studies conducted at the recommended
storage condition should be identified when present at a level greater than (>) the1

Impurities in New Drug Products

identification thresholds given in Attachment 1. When identification of a degradation
product is not feasible, a summary of the laboratory studies demonstrating theunsuccessful efforts to identify it should be included in the registration application.
Degradation products present at a level of not more than () the identificationthreshold generally would not need to be identified. However, analytical proceduresshould be developed for those degradation products that are suspected to be unusuallypotent, producing toxic or significant pharmacological effects at levels not more than() the identification threshold. In unusual circumstances, technical factors (e.g.,
manufacturing capability, a low drug substance to excipient ratio, or the use of
excipients that are crude products of animal or plant origin) can be considered as partof the justification for selection of alternative thresholds based upon manufacturingexperience with the proposed commercial process.
3.
ANALYTICAL PROCEDURES
The registration application should include documented evidence that the analyticalprocedures have been validated and are suitable for the detection and quantitation of
degradation products (see ICH Q2A and Q2B guidelines on analytical validation). In
particular, analytical procedures should be validated to demonstrate specificity for the
specified and unspecified degradation products. As appropriate, this validation should
include samples stored under relevant stress conditions: light, heat, humidity,
acid/base hydrolysis, and oxidation. When an analytical procedure reveals thepresence of other peaks in addition to those of the degradation products (e.g., the drug
substance, impurities arising from the synthesis of the drug substance, excipients andimpurities arising from the excipients), these peaks should be labeled in thechromatograms and their origin(s) discussed in the validation documentation.
The quantitation limit for the analytical procedure should be not more than () thereporting threshold.
Degradation product levels can be measured by a variety of techniques, including
those that compare an analytical response for a degradation product to that of an
appropriate reference standard or to the response of the new drug substance itself.
Reference standards used in the analytical procedures for control of degradation
products should be evaluated and characterised according to their intended uses. The
drug substance can be used to estimate the levels of degradation products. In cases
where the response factors are not close, this practice can still be used if a correction
factor is applied or the degradation products are, in fact, being overestimated.
Acceptance criteria and analytical procedures, used to estimate identified orunidentified degradation products, are often based on analytical assumptions (e.g.,
equivalent detector response). These assumptions should be discussed in theregistration application.
Differences between the analytical procedures used during development and those
proposed for the commercial product should also be discussed.
4.
REPORTING DEGRADATION PRODUCTS CONTENT OF BATCHES
Analytical results should be provided in the registration application for all relevantbatches of the new drug product used for clinical, safety, and stability testing, as wellas batches that are representative of the proposed commercial process. Quantitative
results should be presented numerically, and not in general terms such as “complies”,“meets limit” etc. Any degradation product at a level greater than (>) the reporting2

Impurities in New Drug Products

threshold (see Attachment 1), and total degradation products observed in the relevantbatches of the new drug product, should be reported with the analytical procedures
indicated. Below 1.0%, the results should be reported to the number of decimal places(e.g., 0.06%) in the applicable reporting threshold; at and above 1.0%, the results
should be reported to one decimal place (e.g., 1.3%). Results should be rounded using
conventional rules (see Attachment 2). A tabulation (e.g., spreadsheet) of the data is
recommended. Degradation products should be designated by code number or by anappropriate descriptor, e.g., retention time. If a higher reporting threshold is
proposed, it should be fully justified. All degradation products at a level greater than(>) the reporting threshold should be summed and reported as total degradation
products.
Chromatograms with peaks labelled (or equivalent data if other analytical procedures
are used) from representative batches, including chromatograms from analyticalprocedure validation studies and from long-term and accelerated stability studies,should be provided. The applicant should ensure that complete degradation productprofiles (e.g., chromatograms) of individual batches are available, if requested.
For each batch of the new drug product described in the registration application, thedocumentation should include:Batch identity, strength, and sizeDate of manufacture

Site of manufacture

Manufacturing process

Immediate container closureDegradation product content, individual and totalUse of batch (e.g., clinical studies, stability studies)

Reference to analytical procedure usedBatch number of the drug substance used in the new drug productStorage conditions for stability studies

5.
LISTING OF DEGRADATION PRODUCTS IN SPECIFICATIONSThe specification for a new drug product should include a list of degradation products
expected to occur during manufacture of the commercial product and underrecommended storage conditions. Stability studies, knowledge of degradation
pathways, product development studies, and laboratory studies should be used tocharacterise the degradation profile. The selection of degradation products in the new
drug product specification should be based on the degradation products found inbatches manufactured by the proposed commercial process. Those individualdegradation products with specific acceptance criteria included in the specification for
the new drug product are referred to as "specified degradation products" in thisguideline. Specified degradation products can be identified or unidentified. A
rationale for the inclusion or exclusion of degradation products in the specification
should be presented. This rationale should include a discussion of the degradation
profiles observed in the safety and clinical development batches and in stability
studies, together with a consideration of the degradation profile of batches
manufactured by the proposed commercial process. Specified identified degradation

3

Impurities in New Drug Products

products should be included along with specified unidentified degradation products
estimated to be present at a level greater than (>) the identification threshold given in
Attachment 1. For degradation products known to be unusually potent or to produce
toxic or unexpected pharmacological effects, the quantitation/detection limit of theanalytical procedures should be commensurate with the level at which thedegradation products should be controlled. For unidentified degradation products, theprocedure used and assumptions made in establishing the level of the degradation
product should be clearly stated. Specified unidentified degradation products should
be referred to by an appropriate qualitative analytical descriptive label (e.g.,“unidentified A", “unidentified with relative retention of 0.9”). A general acceptancecriterion of not more than () the identification threshold (Attachment 1) for any
unspecified degradation product and an acceptance criterion for total degradation
products should also be included.
For a given degradation product, its acceptance criterion should be established bytaking into account its acceptance criterion in the drug substance (if applicable), itsqualified level, its increase during stability studies, and the proposed shelf life andrecommended storage conditions for the new drug product.
Furthermore, eachacceptance criterion should be set no higher than the qualified level of the given
degradation product.
Where there is no safety concern, degradation product acceptance criteria should bebased on data generated from batches of the new drug product manufactured by the
proposed commercial process, allowing sufficient latitude to deal with normal
manufacturing and analytical variation and the stability characteristics of the new
drug product. Although normal manufacturing variations are expected, significant
variation in batch-to-batch degradation product levels can indicate that the
manufacturing process of the new drug product is not adequately controlled andvalidated (see ICH Q6A guideline on specifications, decision tree #2, for establishingan acceptance criterion for a specified degradation product in a new drug product).
In this guideline, the use of two decimal places for thresholds (See Attachment 1) does
not necessarily indicate the precision of the acceptance criteria for specified
degradation products and total degradation products.
In summary, the new drug product specification should include, where applicable, thefollowing list of degradation products:Each specified identified degradation productEach specified unidentified degradation productAny unspecified degradation product with an acceptance criterion of not morethan () the identification threshold

Total degradation products.

6.
QUALIFICATION OF DEGRADATION PRODUCTS
Qualification is the process of acquiring and evaluating data that establishes the
biological safety of an individual degradation product or a given degradation profile atthe level(s) specified. The applicant should provide a rationale for establishingdegradation product acceptance criteria that includes safety considerations. The levelof any degradation product present in a new drug product that has been adequately
tested in safety and/or clinical studies would be considered qualified. Therefore, it isuseful to include any available information on the actual content of degradation

4

Impurities in New Drug Products

products in the relevant batches at the time of use in safety and/or clinical studies.
Degradation products that are also significant metabolites present in animal and/or
human studies are generally considered qualified. Degradation products could beconsidered qualified at levels higher than those administered in safety studies basedon a comparison between actual doses given in the safety studies and the intended
dose of the new drug product. Justification of such higher levels should include
consideration of factors such as: (1) the amount of degradation product administeredin previous safety and/or clinical studies and found to be safe; (2) the increase in theamount of the degradation product; and (3) other safety factors, as appropriate.
If the qualification thresholds given in Attachment 1 are exceeded and data areunavailable to qualify the proposed acceptance criterion of a degradation product,
additional studies to obtain such data can be appropriate (see Attachment 3).
Higher or lower thresholds for qualification of degradation products can beappropriate for some individual new drug products based on scientific rationale andlevel of concern, including drug class effects and clinical experience. For example,
qualification can be especially important when there is evidence that suchdegradation products in certain new drug products or therapeutic classes havepreviously been associated with adverse reactions in patients. In these instances, alower qualification threshold can be appropriate. Conversely, a higher qualificationthreshold can be appropriate for individual new drug products when the level ofconcern for safety is less than usual based on similar considerations (e.g., patient
population, drug class effects, and clinical considerations). Proposals for alternative
thresholds would be considered on a case-by-case basis.
The "Decision Tree for Identification and Qualification of a Degradation Product"(Attachment 3) describes considerations for the qualification of degradation products
when thresholds are exceeded. In some cases, reducing the level of degradation
product (e.g., use of a more protective container closure or modified storage
conditions) to not more than () the threshold can be simpler than providing safety
data. Alternatively, adequate data could be available in the scientific literature toqualify a degradation product. If neither is the case, additional safety testing should
be considered. The studies considered appropriate to qualify a degradation productwill depend on a number of factors, including the patient population, daily dose, androute and duration of new drug product administration. Such studies can be
conducted on the new drug product or substance containing the degradation products
to be controlled, although studies using isolated degradation products can sometimes
be appropriate.
Although this guideline is not intended to apply during the clinical research stage ofdevelopment, in the later stages of development the thresholds in this guideline canbe useful in evaluating new degradation products observed in new drug productbatches prepared by the proposed commercial process. Any new degradation productobserved in later stages of development should be identified (see the “Decision Treefor Identification and Qualification of a Degradation Product” in Attachment 3) if its
level is greater than (>) the identification threshold given in Attachment 1. Similarly,
qualification of the degradation product should be considered if its level is greaterthan (>) the qualification threshold given in Attachment 1.
Safety studies should provide a comparison of results of safety testing of the new drug
product or drug substance containing a representative level of the degradation

5

Impurities in New Drug Products

product with previously qualified material, although studies using the isolateddegradation products can also be considered.
7.
GLOSSARY
Degradation Product: An impurity resulting from a chemical change in the drug
substance brought about during manufacture and/or storage of the new drug productby the effect of, for example, light, temperature, pH, water, or by reaction with an
excipient and/or the immediate container closure system.
Degradation Profile: A description of the degradation products observed in the drug
substance or drug product.
Development Studies: Studies conducted to scale-up, optimise, and validate the
manufacturing process for a drug product.
Identification Threshold: A limit above (>) which a degradation product should be
identified.
Identified Degradation Product: A degradation product for which a structuralcharacterisation has been achieved.
Impurity: Any component of the new drug product that is not the drug substance oran excipient in the drug product.
Impurity Profile: A description of the identified and unidentified impurities present
in a drug product.
New Drug Substance: The designated therapeutic moiety that has not beenpreviously registered in a region or member state (also referred to as a new molecular
entity or new chemical entity). It can be a complex, simple ester, or salt of apreviously approved substance.
Qualification: The process of acquiring and evaluating data that establishes the
biological safety of an individual degradation product or a given degradation profile atthe level(s) specified.
Qualification Threshold: A limit above (>) which a degradation product should be
qualified.
Reporting Threshold: A limit above (>) which a degradation product should bereported.
Specified Degradation Product: A degradation product that is individually listed
and limited with a specific acceptance criterion in the new drug product specification.
A specified degradation product can be either identified or unidentified.
Unidentified Degradation Product: A degradation product for which a structuralcharacterisation has not been achieved and that is defined solely by qualitative
analytical properties (e.g., chromatographic retention time).
Unspecified Degradation Product: A degradation product that is limited by ageneral acceptance criterion, but not individually listed with its own specificacceptance criterion, in the new drug product specification.

6

Impurities in New Drug Products

Attachment 1: Thresholds for Degradation Products in New Drug Products
Reporting Thresholds

Maximum Daily Dose1

Threshold2,3

1 g
>1g

0.1%
0.05%
Identification Thresholds

Maximum Daily Dose1

Threshold2, 3< 1 mg
1 mg - 10 mg>10 mg - 2 g> 2g

1.0% or 5 µg TDI, whichever is lower
0.5% or 20 µg TDI, whichever is lower
0.2% or 2 mg TDI, whichever is lower
0.10%
Qualification Thresholds

Maximum Daily Dose1

Threshold2,3< 10 mg
10 mg - 100 mg>100 mg - 2 g>2g

1.0% or 50 µg TDI, whichever is lower
0.5% or 200 µg TDI, whichever is lower
0.2% or 3 mg TDI, whichever is lower
0.15%

Notes on Attachment 1
1

The amount of drug substance administered per day

2

Thresholds for degradation products are expressed either as a percentage of the drug
substance or as total daily intake (TDI) of the degradation product. Lower thresholds
can be appropriate if the degradation product is unusually toxic.

3

Higher thresholds should be scientifically justified.

7

Impurities in New Drug Products

Illustration of Thresholds for Reporting, Identification, and Qualification of
Degradation Products in New Drug Products as a Function of1
Maximum Daily Dose

Reporting

1.00

Qualification

0.80

0.60

0.40

0.20

0.00
0

500

1000

1500

2000

2500

Maximum Daily Dose Expressed in mg of Drug SubstanceExpanded Scale:
1.00

Reporting

Percentage of Drug Substance

Percentage of Drug Substance

Identification

Identification

0.80

Qualification
0.60

0.40

0.20

0.00
0

5

10

15

Maximum Daily Dose Expressed in mg of Drug Substance
1 Note : Actual threshold values should be taken from the preceding table in this attachment.

820Impurities in New Drug Products

Attachment 2: Illustration of Reporting Degradation Product Resultsfor Identification and Qualification in an Application
The attachment is only illustrative and is not intended to serve as a template how
results on degradation products should be presented in an application file. Normally
raw data are not provided.
Example 1: 50 mg Maximum Daily Dose
Reporting threshold: 0.1%
Identification threshold: 0.2%
Qualification threshold: 200 μg'Raw' Result

Reported
Result(%)

Total Daily
ActionIntake (TDI)
Identification Qualificationof theThresholdThreshold(%)
Degradation
Product
0.2%
200 μg TDI(Reporting
Threshold =(roundedexceeded?
exceeded?
0.1%)
result in μg)

0.04

Not reported

20

None

None

0.2143

0.2

100

None

None

0.349

0.31

150

Yes

None1

0.550

0.61

300

Yes

Yes1

Example 2: 1.9 gram Maximum Daily Dose
Reporting threshold: 0.05%
Identification threshold: 2 mg
Qualification threshold: 3 mg
'Raw' Result(%)

Reported
Result(%)(Reporting
Threshold =0.05%)

Total Daily
Intake (TDI)of theDegradation
Product

ActionIdentification Qualification
ThresholdThreshold
2 mg TDI

3 mg TDI(rounded
result in mg)

exceeded?

exceeded?

0.049

Not
reported

1

None

None

0.079

0.08

2

None

None

0.183

0.181

3

Yes

None1, 2

0.192

0.191

4

Yes

Yes1

9

Impurities in New Drug Products

Notes on attachment 2
1

After identification, if the response factor is determined to differ significantly
from the original assumptions, it can be appropriate to re-measure the actual
amount of the degradation product present and re-evaluate against thequalification threshold (see Attachment 1).

2

To verify if a threshold is exceeded, a reported result has to be evaluatedagainst the thresholds as follows: when the threshold is described in %, thereported result rounded to the same decimal place as the threshold should becompared directly to the threshold. When the threshold is described in TDI,
the reported result should be converted to TDI, rounded to the same decimal
place as the threshold and compared to the threshold e.g. an amount of 0.18%
degradation level corresponds to a TDI of 3.4 mg impurity (absolute amount)which is then rounded down to 3 mg; so the qualification threshold expressedin TDI (3 mg) is not exceeded.

10Impurities in New Drug Products

Attachment 3: Decision Tree for Identification and Qualification of a
Degradation ProductIs degradation
product greater thanidentificationthresholdc?

Yes

Structure
identified?

No

No actionAnyknown humanrelevant risksd?

Yes

Yes

Reduce tosafe level

No
No

Reduceto not more than() identificationthresholdc?

Yes

No further
actionYes
No
Reduceto not more than() qualificationthresholdc?

Yes

Greaterthan qualificationthresholdc?

No

Consider patient population and duration of use
and consider conducting:Genotoxicity studies (point mutation,
chromosomal aberration)a
General toxicity studies (one species, usually
14 to 90 days)b
Other specific toxicity endpoints, as
appropriate

Reduce tosafe level

Yes

Any
clinically
relevant adverse
effects?

11

No

QualifiedNo
No action

Impurities in New Drug Products

Notes on Attachment 3a)

If considered desirable, a minimum screen (e.g., genotoxic potential), should be
conducted.
A study to detect point mutations and one to detect chromosomal aberrations,both in vitro, are considered an appropriate minimum screen.

b)

If general toxicity studies are desirable, one or more studies should bedesigned to allow comparison of unqualified to qualified material. The study
duration should be based on available relevant information and performed in
the species most likely to maximise the potential to detect the toxicity of adegradation product. On a case-by-case basis, single-dose studies can beappropriate, especially for single-dose drugs. In general, a minimum durationof 14 days and a maximum duration of 90 days would be consideredappropriate.

c)

Lower thresholds can be appropriate if the degradation product is unusually
toxic.

d)For example, do known safety data for this degradation product or its
structural class preclude human exposure at the concentration present?

12