#216 
 
Guidance for Industry 
 
Chemistry, Manufacturing, and Controls (CMC) 
Information  Fermentation-Derived 
Intermediates, Drug Substances, and Related 
Drug Products for Veterinary Medicinal Use 
 
 
 
Comments and suggestions regarding this guidance should be sent to the Division of Dockets 
Management (HFA-305), Food and Drug Administration, 5630 Fishers Lane, Room 1061, 
Rockville, MD 20852. Comments can be submitted electronically on the Internet at 
http://www.regulations.gov. All written comments should be identified with the Docket No. 
FDA-2011-D-0112. 
  
For questions regarding this document, contact Michael J. Popek, Center for Veterinary 
Medicine, (HFV-144), Food and Drug Administration, 7500 Standish Place, Rockville, MD 
20855, (240) 276-8269, e-mail: michael.popek@fda.hhs.gov.  
 
Additional copies of this guidance document can be requested from the Communications Staff 
(HFV-12), Center for Veterinary Medicine, Food and Drug Administration, 7519 Standish Place, 
Rockville, MD 20855, and may be viewed on the Internet at 
http://www.fda.gov/AnimalVeterinary/GuidanceComplianceEnforcement/GuidanceforIndustry/d
efault.htm. 
  
U.S. Department of Health and Human Services  
Food and Drug Administration  
Center for Veterinary Medicine  
March 8, 2012 
  Contains Nonbinding Recommendations 
 
TABLE OF CONTENTS 
 
 
 
I.  INTRODUCTION.............................................................................................................4 
II.  BACKGROUND...............................................................................................................4 
III.  SCOPE...............................................................................................................................5 
IV.  INTERMEDIATES, DRUG SUBSTANCES, DRUG PRODUCTS.............................5 
A.  Identification of Manufacturing Facilities...................................................................................6 
B.  Description of Manufacturing Process and Controls.................................................................6 
1. Pharmaceutical Development Reports.............................................................................................6 
2. Cell Growth (Propagation) and Harvest.........................................................................................6 
3. Purification and Downstream Processing.......................................................................................7 
4. Modification Reactions (If Applicable)............................................................................................8 
a.  Chemical Modifications............................................................................................................8 
b.  Enzymatic Modifications..........................................................................................................8 
5.  Reprocessing, Reworking, Recycling, Regeneration, and Salvaging..............................................8 
C.  Control of Materials......................................................................................................................8 
1.  Microorganism................................................................................................................................8 
2. Cell Bank System.............................................................................................................................9 
a.  Master Cell Bank......................................................................................................................9 
b.  Working Cell Bank...................................................................................................................9 
3. Media Components..........................................................................................................................9 
4. Solvents, Reagents, Auxiliary Materials..........................................................................................9 
D.  Control of Critical Steps and Intermediates..............................................................................10 
E.  Non-Critical In-Process Controls...............................................................................................10 
F.  Process Validation and/or Evaluation........................................................................................10 
G.  Characterization..........................................................................................................................10 
1. Elucidation of Structure and other Characteristics.......................................................................10 
a.  Structural Elucidation.............................................................................................................11 
b.  Physicochemical Characterization..........................................................................................11 
c.  Biological Activity..................................................................................................................11 
2. Impurities.......................................................................................................................................11 
3. Degradation Products....................................................................................................................13 
H.  Control of Intermediates, Drug Substances, and Drug Products............................................13 
1. Specifications.................................................................................................................................13 
2. Analytical Procedures....................................................................................................................13 
3. Validation of Analytical Procedures..............................................................................................14 
4. Reference Standards or Materials.................................................................................................14 
5. Batch Analyses...............................................................................................................................14 
I.  Container Closure System...........................................................................................................14 
J.  Labeling........................................................................................................................................14 
K.  Stability Summary and Conclusions..........................................................................................15  Contains Nonbinding Recommendations 
 
1. Batch Selection for Stability Studies..............................................................................................15 
2. Expiration Date versus Retest Date...............................................................................................15 
3. Postapproval Stability Protocol and Commitment........................................................................16 
4. Stability Data.................................................................................................................................16  Contains Nonbinding Recommendations 
 
Guidance for Industry  
 
Chemistry, Manufacturing, and Controls (CMC) Information 
 Fermentation-Derived Intermediates, Drug Substances, and 
Related Drug Products for Veterinary Medicinal Use  
 
This will represent the Centers current thinking on the topic. It does not create or confer any 
rights for or on any person and does not operate to bind FDA or the public. You can use an 
alternative approach if the approach satisfies the requirements of the applicable statutes and 
regulations. If you want to discuss an alternative approach, contact the FDA staff responsible 
for implementing this guidance. If you cannot identify the appropriate FDA staff, call the 
appropriate number listed on the title page of this guidance. 
  
 
 
I.  INTRODUCTION 
  
This guidance provides recommendations on what documentation to submit to support the 
chemistry, manufacturing, and controls (CMC) information for fermentation-derived 
intermediates, drug substances, and related drug products for veterinary medicinal use.  This 
information is filed to the Center for Veterinary Medicine (CVM) in a new animal drug 
application (NADA), conditional new animal drug application (CNADA), investigational new 
animal drug file (INAD), abbreviated new animal drug application (ANADA), generic 
investigational new animal drug file (JINAD), drug master file (DMF), or veterinary master file 
(VMF). 
 
FDAs guidance documents, including this guidance, do not establish legally enforceable 
responsibilities.  Instead, guidances describe the Agencys current thinking on a topic and 
should be viewed only as recommendations, unless specific regulatory or statutory 
requirements are cited.  The use of the word should in Agency guidances means that 
something is suggested or recommended, but not required. 
 
 
 
II.  BACKGROUND  
 
Fermentation processes are frequently used to manufacture intermediates, drug substances, and 
related drug products for veterinary medicinal use.  Traditionally, most manufactured 
fermentation products were extracted from the media or cell mass and either further purified or 
molecularly modified to create another entity.  Today, a variety of products are manufactured 
from fermentation processes, including:  
 
  Biomass products (i.e., drug and cell mass constitute the product) 
  Competitive exclusion products (i.e., the product consists of one or more microorganisms 
intended to exclude harmful bacteria, such as Salmonella, from colonizing) 
  Biotech products 
 
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  Bacteriophage products 
 
Microbial systems can introduce manufacturing variability that can affect the purity and quality, 
and ultimately, the safety and effectiveness of a product, if not controlled.  Even though 
fermentation is a common manufacturing practice, CVM currently provides no CMC guidance to 
pharmaceutical sponsors about fermentation-derived intermediates, drug substances, or related 
drug products. 
 
 
III.  SCOPE  
 
Filing information for the CMC of a new animal drug application is described in 21 CFR 514.  
The first specific mention of CMC requirements for fermentation products occurs in 21 CFR 
514.1(b)(4)(iii)(a-e) in the Component and Composition section.   Most other required CMC 
information is described in 21 CFR 514.1(b)(5).  This guidance provides recommendations for 
CMC information to support fermentation-derived intermediates, drug substances, and related 
drug products intended for veterinary use. 
 
The information in this guidance loosely follows the International Conference on Harmonisation 
(ICH) Common Technical Document (CTD).  Due to the redundancy of information between 
fermentation-derived intermediates, drug substances, and drug products, sections were combined 
and are not specifically labeled in the CTD format (e.g. Description of Manufacturing Process 
and Process Controls (S.2.2)).  In addition, some CTD sections may have been omitted as they are 
common to all intermediates, drug substances, and drug products (e.g. General Information), 
whether or not they relate to fermentation.  CVM will accept quality related documents in CTD 
format.  
 
This guidance does not address postapproval changes associated with fermentation-derived 
products.  Although the guidance addresses fermentation issues associated with semi-synthetic 
drug substances, it only provides limited information for some semi-synthetic steps post-
fermentation.  More detailed post-fermentation recommendations can be found in the CVM 
guidance for industry 169: Drug Substance Chemistry, Manufacturing, and Controls Information.  
Additionally, this guidance does not address special characterization and control requirements for 
biomass, competitive exclusion, phage, and other fermentation-related products produced by 
microorganisms genetically engineered using recombinant DNA (rDNA) technology.  Even 
though these products are not specifically covered, the underlying fermentation principles 
described in this document would be applicable to these products as well.  
 
 
IV.  INTERMEDIATES, DRUG SUBSTANCES, DRUG PRODUCTS 
 
CMC information for fermentation-derived intermediates, drug substances, and related drug 
products can be provided directly in a NADA, CNADA, INAD, ANADA, or JINAD.  Typically, 
the information for intermediates and drug substances are provided by reference to a DMF or a 
VMF. 
 
Master files provide an avenue for manufacturers to submit proprietary information to the Agency 
without submitting that information to the applicant.  Master files can also be used by a drug 
sponsor as an organizational tool for different processes (e.g., to separate the process for drug 
substance manufacturing from the finished dosage form process).  For the Agency to review a 
 
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DMF or VMF, a letter of authorization (LOA) from the DMF or VMF holder should be submitted 
as part of the referencing submission provided by the applicant.     
 
The following describes information that should be provided in either a master file(s) or an 
application, depending on which is used. 
 
A.  Identification of Manufacturing Facilities 
 
Facilities involved in the manufacture and/or testing (including contract manufacturers and 
testing laboratories) of fermentation-derived intermediates, drug substances, and related drug 
products should be identified.  The name, address, and manufacturing responsibility 
operations/processes performed should be provided for each firm. 
 
B.  Description of Manufacturing Process and Controls 
 
A detailed description of the manufacturing process and process controls should be provided for 
intermediates, drug substances, and related drug products: 
  Describe the entire process (including original inoculum, propagation, harvest, 
isolation/purification, and any modification reactions) 
  Identify all process controls   
For drug products, a master batch record covering the entire process including original inoculum, 
propagation, harvest, isolation/purification, and any modification reactions should be provided.    
 
Recommendations for executed (completed) batch records are provided in CVM guidance for 
industry 42:  Animal Drug Manufacturing Guidelines-Series of Four Guidelines (1994).   CVM 
encourages the submission of executed batch records for lots of drug substance and drug product 
used in support of the application as they provide valuable detail and insight into the 
manufacturing process and proposed controls. 
 
1.  Pharmaceutical Development Reports 
 
Sponsors are encouraged to provide pharmaceutical development reports (PDRs) that describe the 
scientific rationale for the chosen manufacturing process(es) and controls for fermentation-
derived intermediates, drug substances, and related drug products.  A sponsors ability to 
demonstrate process understanding can be factored into CVMs risk-based decision making (e.g., 
Pre-Approval Inspection Decision Support System (PAIDSS)).  Suggestions for PDRs can be 
found in ICH Q8: Pharmaceutical Development. 
 
2.  Cell Growth (Propagation) and Harvest 
   
A description should be provided that includes a flow diagram illustrating each step in 
propagation from the original inoculum (e.g., cells from one or more vials of the working cell 
bank) through the last harvesting operation. 
  All steps should be included along with the relevant information, such as the growth 
conditions and in-process tests performed (e.g., cell concentrations, volumes, pH, 
cultivation times, temperatures). 
  Critical steps and intermediates for which specifications are established should be 
identified, along with sampling plans and testing time points. 
 
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  Contains Nonbinding Recommendations 
 
  The flow diagram can be supplemented with information presented in tabular form, if 
appropriate. 
 
A narrative describing each manufacturing step in the process should accompany the flow 
diagram: 
  Identify all process controls and the associated numeric ranges, limits, or acceptance 
criteria 
  Highlight any process controls that are considered critical 
  Identify the intended scale of the process.   The amounts indicated should be 
representative of a maximum-sized production batch. 
 
We recommend the following be included in the narrative: 
  A description of the major equipment involved in each step 
  A description of inoculation and each step in propagation with growth conditions 
specified 
  The composition of the media used at each step, including water quality and additives 
used 
  The sterilization procedures for media (e.g. a batch sterilization process or continuous 
system) 
  The equipment (e.g. fermentation vessel), feeds, and other materials added during 
the fermentation process 
  Process parameters monitored and controls for critical steps and intermediates 
  Procedures used to transfer material between steps 
  Procedures used to minimize contamination by adventitious agents 
  Process controls to confirm the effectiveness of the specific manufacturing steps used 
to inactivate and or remove adventitious agents 
  Criteria for harvesting 
  Criteria for rejecting/accepting a fermentation batch if contamination occurs 
  The determination of yields 
  Criteria for pooling more than one harvest, if applicable 
  Storage conditions and time limits if the harvested crude fermentation product is held 
prior to further processing 
 
3.  Purification and Downstream Processing 
 
The description should include a flow diagram that illustrates and a narrative that describes all the 
steps involved in isolating and purifying the crude fermentation product to its final form, along 
with any relevant information (e.g., volumes, pH, temperatures, holding times).  Critical steps and 
intermediates for which specifications are established should be identified, along with testing 
time points. 
 
The narrative describing each manufacturing step should accompany the flow diagram and should 
identify all process controls and the associated numeric ranges, limits, or acceptance criteria and 
include the following: 
 
  Methods used in purification or separation of the crude fermentation product (e.g. 
precipitation, centrifugation, filtration) including major equipment (e.g. columns, 
membranes 
 
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  Contains Nonbinding Recommendations 
 
  Process parameters monitored 
  The in-process controls and analytical tests used to show identity, purity, and 
concentration and to evaluate levels of process- and product-related impurities  
  The determination of yields 
  Precautions taken to prevent or control microbial contamination during purification 
  Conditions for reuse and/or procedures for regeneration of columns, membranes, and 
adsorbents 
  Storage conditions and time limits, if the purified fermentation product is held prior to 
further processing 
 
4.  Modification Reactions (If Applicable) 
 
a.  Chemical Modifications 
 
When a product of fermentation is to be subjected to further molecular change through chemical 
means, a description of the synthetic steps should be included in the procedural narrative.  
Additionally, a flow diagram of the synthetic process should be provided.  For more details, see 
CVM guidance for industry 169: Drug Substance: Chemistry, Manufacturing, and Controls 
Information. 
 
b.  Enzymatic Modifications 
   
When the fermentation product is further modified using enzyme catalysts, the steps should be 
included in the flow diagram and detailed in the procedural narrative.  Enzymatic reactions are 
considered chemical reactions since the conversion of substrate product involves breaking and 
forming chemical bonds.  Thus, much of the information submitted in the manufacturing 
description should be the same as that submitted for chemical processes (drug substance). 
However, because enzymatic functionality requires carefully controlled conditions (e.g., pH, 
temperature, osmolarity), the description should contain detailed information on reaction controls 
and the optimum range of operation.  Furthermore, the biological source of the enzyme should be 
provided along with a description of the enzymes preparation and information about its purity. 
 
5.   Reprocessing, Reworking, Recycling, Regeneration, and Salvaging 
 
When appropriate, reprocessing, reworking, recycling, regeneration, and salvaging operations 
should be described.  For more detail, see CVM guidance for industry 169: Drug Substance: 
Chemistry, Manufacturing, and Controls Information. 
 
 
C.  Control of Materials 
 
A list of materials used in the manufacture of fermentation-derived intermediates, drug 
substances, and drug products should be provided (i.e., the microorganism, cell bank system, 
media components, solvents, reagents, auxiliary materials).  Information pertaining to the quality 
and control of these materials should also be provided. 
 
1.   Microorganism 
 
 
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  Contains Nonbinding Recommendations 
 
Information about the microorganism used for production (i.e., genus, species, and type strain) 
and known genotypic and phenotypic characteristics should be provided.  Additionally, the origin 
of the source material (or isolate) should be identified or described. 
 
2.  Cell Bank System 
 
a.  Master Cell Bank 
 
A brief description of the procedures used to generate the master cell bank (MCB) and the criteria 
used for qualification should be provided.  The information should include: 
 
  Method, reagents, and media used in preparation 
  Date of preparation 
  Process controls 
  Storage conditions 
  Procedures used in testing for relevant phenotypic and genotypic markers and 
determining culture purity 
  Procedures used to ensure the absence of contamination from adventitious agents (e.g., 
microbial contamination and crosscontamination by other cell types) with tests and 
acceptance criteria specified 
 
b.  Working Cell Bank 
 
Preservation of the microbial purity of the MCB is an important factor in maintaining the 
production strain.  Often a working cell bank (WCB) is created so that the MCB will be less 
likely to be compromised.  Creation of a WCB occurs via the propagation of the MCB through 
defined culture conditions, and then aliquots of the resultant homogenous culture suspension are 
partitioned into individual storage containers of appropriate size for routine production purposes. 
 
A brief description of the procedures used to derive a WCB from the MCB and the criteria used 
for qualification should be provided.  Information similar to that submitted for the MCB should 
also be submitted for the WCB. 
 
3.  Media Components 
 
A list of the media components used at each stage of the fermentation process should be included 
in the submission.  Specifications should be provided for each component for verification that the 
material is of suitable quality for its intended purpose. 
 
  If ruminant-based media components are used in the fermentation process, they should 
comply with the proposed BSE Medical Products Rule, issued on January 12, 2007 (72 
FR 1582). 
  All animal-derived components should be identified and appropriate mitigation steps 
taken to prevent the transmission of adventitious agents. 
 
4.  Solvents, Reagents, Auxiliary Materials 
 
A list of solvents, reagents, and other auxiliary materials used in the fermentation process should 
be provided.  Specifications for each material should be included for verification that the material 
 
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is of suitable quality for its intended purpose.  When water is used in the process, it should be of 
an appropriate quality for its intended use. 
 
D.  Control of Critical Steps and Intermediates 
 
All critical process controls and their associated numeric ranges, limits, or acceptance criteria 
should be identified and justified and a brief description of the test provided.  Furthermore, any 
experimental data to support the justification should be included. 
 
  Good controls are essential during fermentation to ensure product consistency. 
  End product testing alone is not adequate for demonstrating a fermentation process is 
under control. 
  Manufacturing processes, including fermentation, should be controlled to ensure 
that the product meets previously identified quality attributes. 
 
All controls used in determining an isolated intermediates acceptability for downstream 
processing should be identified.  When the intermediate represents the end of the fermentation 
process and the beginning of a synthetic scheme, the controls warranted are generally more 
extensive than those used for other types of intermediates.  For more detail, see CVM guidance 
for industry 169: Drug Substance: Chemistry, Manufacturing, and Controls Information. 
 
E.  Non-Critical In-Process Controls 
 
CVM encourages sponsors to identify and describe non-critical in-process controls conducted on 
a routine basis (e.g., carbohydrate burn rate, may affect yield, but wont necessarily affect product 
quality).  Although these controls may not directly demonstrate that a process produces a quality 
product, a description of the tests being conducted and why they are not critical, aid in 
demonstrating process understanding. 
 
F.  Process Validation and/or Evaluation 
 
When a fermentation-derived intermediate, drug substance, or drug product is sterilized, the 
process validation information and data in support of the sterilization process(es) should be 
provided.  Refer to CVM guidance for industry 48:  For the Submission of Documentation for 
Sterilization Process Validation In Applications For Human And Veterinary Drug Products. 
 
Non-sterile process validation is conducted prior to commercial marketing.  CVM may request 
that process validation protocols and data be submitted in support of manufacturing processes.  
Scale-up issues encountered during process validation and any modifications to the process to 
accommodate these issues must be reported through the appropriate postapproval submission 
process (see 21 CFR 514.8(b)).   
 
G.  Characterization 
 
1.  Elucidation of Structure and other Characteristics 
 
Confirmation of the structure and characterization data for a fermentation-derived intermediate, 
drug substance, or drug product should be provided.  When the fermentation product is a mixture 
of active components, isolation and purification of individual components for structural analysis 
and characterization may be appropriate. 
 
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  Contains Nonbinding Recommendations 
 
 
a.  Structural Elucidation 
 
Structural confirmation using physical and chemical techniques (e.g., elemental analysis, mass 
spectrometry, infrared spectroscopy) should be provided for the intermediate or drug substance.  
Additionally, the data and details of its interpretation should be included.  The amount of data 
warranted to support the elucidation of structure can vary depending on the complexity of the 
molecule.  For USP labeled drug substances, structural confirmation can be accomplished by 
demonstrating conformance to a USP reference standard. 
 
b.  Physicochemical Characterization 
 
The kind and extent of the physicochemical characterization information that should be 
provided depends on (1) the type of drug substance (e.g., semi-synthetic molecule, protein), 
(2) the type of dosage form in which the drug substance will be used, (3) the ability or 
tendency of the drug substance to occur in one or more solid state forms, and (4) the 
importance of the differences in physical characteristics of the different forms to the stability, 
dissolution, or bioavailability of the drug product.  For more details on the type of information 
that should be submitted, see CVM guidance for industry 169: Drug Substance: Chemistry, 
Manufacturing, and Controls Information, Draft Guidance. 
 
c.  Biological Activity 
 
When a biological assay (e.g., antimicrobial activity for antibiotics) is used to assess 
potency/strength of the intermediate or drug substance, biological activity data should be 
provided to complete the characterization profile.  Data should be provided on the reference 
standard lot or other relevant lots to demonstrate the potency/strength of the intermediate, drug 
substance, or drug product. 
 
In some cases, the product of fermentation is a complex mixture of major and minor components 
that together make up a products biological activity.  In evaluating the impurity profile for these 
fermentation products, efforts should be made to identify and characterize the active components 
(major and minor) that contribute to the products overall potency and distinguish them from 
impurities.  This may not be practical or feasible in all cases.  We recommend an applicant with 
related questions consult the appropriate review team for additional guidance. 
 
2.  Impurities 
 
Information concerning impurities in the fermentation-derived intermediate, drug substance, or 
drug product should be provided (e.g., organic impurities, inorganic impurities, and residual 
solvents). 
 
  Impurities may derive from the manufacturing process (e.g., residual media components, 
residual protein and nucleic acid derived from microbial cells, processing reagents, 
inorganic salts, filter aids, solvents), or they may be structurally related to the desired 
fermentation product, but not share the same properties with respect to biological activity, 
efficacy, and safety (e.g., other microbial metabolites, precursors, by-products). 
  Process related impurities derived from the fermentation and downstream processing 
should be minimized as much as possible through the use of a well-controlled and 
reproducible manufacturing process. 
 
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  Structurally related impurities should be identified, tracked, and controlled throughout the 
fermentation, isolation, and purification processes. 
 
A summary should be provided of the impurities most likely to arise during the fermentation, 
isolation, purification, and storage (e.g., holding time) of the intermediate, drug substance, or 
drug product.  The summary should include impurity profiles (i.e., chromatograms), test results 
from representative batches, and results from forced degradation studies used to identify the 
potential impurities that may arise during storage. The impurities reported can be of known 
structure, partially characterized, or unidentified.  Studies done in characterizing the structure of 
impurities should be summarized. Documentation should also be provided demonstrating that the 
analytical procedures used in quantifying impurities are properly validated or qualified. 
 
The specifications for fermentation-derived intermediate, drug substance, or drug products should 
include limits for impurities (i.e., organic impurities, inorganic impurities, and residual solvents).  
Additionally, a rationale for the inclusion or exclusion of impurities in the specifications should 
be presented.  As appropriate, this rationale should include a discussion of the impurity profiles 
observed in batches used for clinical, safety, and stability testing, as well as batches 
representative of the proposed commercial process. 
 
Although relevant guidances (92: Impurities in New Veterinary Drug Substances, VICH GL10 
(R) and 93: Impurities in New Veterinary Medical Products, VICH GL11(R)) on impurities did 
not address fermentation products, the principles described in these guidances are still applicable.  
Furthermore, levels for reporting, identifying, and qualifying organic impurities as described in 
these guidances are applicable to non-complex, well-characterized fermentation products. 
 
For complex fermentation products that are not well-characterized in terms of structure, 
physicochemical properties, biological activity, and purity, it is recommended that the levels for 
organic impurities be determined on a case-by-case basis. 
 
The acceptable levels for organic impurities will also depend on how the fermentation product is 
to be used.  The levels will likely be less stringent for a drug substance or an intermediate that 
will be subjected to further modification and/or purification compared to that of a drug product 
that does not undergo further processing. 
  
For inorganic impurities and residual solvents, limits should generally be based on pharmacopeial 
standards (e.g., USP General Chapter <467> Residual Solvents) or known safety data.  
Additionally, the ICH guidance Q3C Impurities: Residual Solvents or the CVM guidance 100:  
Impurities:  Residual Solvents in New Veterinary Medical Products, Active Substances, and 
Excipients, VICH GL18(R) should be consulted, as appropriate.   
 
For most fermentation products (e.g., antibiotics), it is expected that purification and downstream 
processing effectively remove process-related impurities, such as residual media components, 
residual protein and nucleic acid-derived from microbial cells, and other processing reagents. 
Thus, in most cases, limits need not be included in the specification for these impurities.  
However, when studies suggest that process-related impurities are not effectively removed from 
the purification process, these impurities should be controlled with limits in the specifications, as 
appropriate. 
 
Microbial impurities tests (e.g., for endotoxins) for drug products may be required based on the 
intended route of administration of the drug product in accordance with 21 CFR 514.1(5)(xi).  In 
some instances when there is a safety concern, drug substances (e.g., gentamicin sulfate) may 
 
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contain an endotoxin requirement.  Consult the appropriate USP monograph or consult the 
appropriate review team as needed. 
 
3.  Degradation Products 
 
Degradation products observed during stability studies of the drug substance or drug product 
should be summarized, including: 
  Product-related impurities arising from degradation of the drug substance and reaction 
products of the drug substance with an excipient and/or a component of the 
container/closure system 
  Test results from representative batches and results from forced degradation studies on 
the drug substance or product 
 
Studies done in characterizing the structure of the degradation products should be provided. 
Documentation that analytical procedures used in quantifying degradation products are properly 
validated or qualified should also be provided. 
 
Specifications for the drug substance or drug product should include limits for degradation 
products expected to occur under recommended storage conditions.  A rationale for the exclusion 
of a degradation product in the specification should be provided. 
 
H.  Control of Intermediates, Drug Substances, and Drug Products 
 
1.  Specifications 
 
The proposed specifications for the fermentation-derived intermediate, drug substance, or drug 
products should be provided and include the tests that will be performed on each batch, a 
reference to the analytical procedure used in performing the test, and the acceptance criteria for 
each test.  The specifications should focus on those characteristics found to be useful in ensuring 
the safety and efficacy of the intermediate or drug substance. With regard to intermediates, the 
above recommendations are more specific to those intermediates marketed for resale.  
Justification for the proposed specifications for the intermediate, drug substance, and drug 
product should be provided. 
 
For some fermentation-derived drug substances, a nonspecific bioassay (e.g., microbiological 
type assays for antibiotics) is proposed for use in determining the content of the drug substance.  
In these cases, the development of a specific, stability-indicating assay (e.g., High Performance 
Liquid Chromatography (HPLC)) is encouraged as it offers considerable advantages in terms of 
separation of components, accuracy, and precision.  Nevertheless, a nonspecific assay may be 
used when justified (e.g., the USP monograph prescribes a nonspecific assay method).  However, 
when an adequately justified nonspecific assay is employed it should be accompanied by other 
supporting analytical procedures to achieve overall accuracy and specificity.  For example, where 
antimicrobial activity or an iodometric titration is used to assay the drug substance, it should be 
combined with a suitable test for impurities. 
 
2.  Analytical Procedures 
 
Copies of the analytical procedures used in testing the fermentation-derived intermediate, drug 
substance, or drug product should be provided.  However, specific citations may be used when 
 
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the analytical procedure is from an official compendium or other FDA-recognized standard 
reference and the analytical procedure is not modified in any way. 
 
3.  Validation of Analytical Procedures 
 
Validation data for the analytical procedures used in testing the fermentation-derived 
intermediate, drug substance, or drug product should be provided.  For analytical procedures 
defined in the USP, qualification data demonstrating the users capability to successfully perform 
the analytical method is suitable.   
 
4.  Reference Standards or Materials 
 
Information pertaining to reference standards or reference materials used for testing should be 
provided.  Relevant information includes, for example, characterization, storage conditions, 
working solutions, and stability of the reference standard. 
 
5.  Batch Analyses 
 
Batch analysis data using the proposed analytical procedures and specifications for all relevant 
batches of the intermediate, drug substance, or drug product from safety batches (pharmacology 
and/or toxicology), clinical batches for safety and efficacy, bioavailability/bioequivalence 
batches, stability batches, and batches representative of the proposed commercial process should 
be provided. 
 
I.  Container Closure System 
 
A description of the container closure system for fermentation-derived intermediates, drug 
substances, and drug products should be provided.  In addition, a description of the storage 
containers for the MCB and WCB should be provided. 
 
The supplier of each component (excludes MCB and WCB containers) should be identified and 
letters of authorization to master files for raw material component manufacturing should be 
provided. 
 
  Schematics and raw material specification sheets for the components should also be 
included. 
  If components are irradiated, pre-sterilized by other means, or pre-washed, information 
should be submitted in support of these processes.  This information is often provided 
through a reference to a VMF or DMF. 
  Container closure systems for drug substances and finished dosage forms should also 
meet USP monograph specifications and should be tested as appropriate to USP General 
Chapter <661> Containers and if applicable, USP General Chapter <671> Containers-
Permeation. 
 
J.  Labeling 
 
Copies of primary and secondary packaging labels for fermentation-derived intermediates (for 
resale), drug substances, and drug products should be provided.  For intermediates and drug 
substances, the following should be included on the label: 
 
 
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  Name of the chemical entity 
  Number of units or micrograms of activity per milligram when activity is expressed 
in biological terms 
  Number of grams or kilograms in the immediate container 
  Batch or lot number 
  Statement Sterile or Non-sterile 
  Expiration or retest date, as supported by appropriate stability studies 
  Storage conditions 1 
 
For fermentation-derived drug products, the usual labeling procedures for non-fermentation-
derived drug products should be followed. 
 
K.  Stability Summary and Conclusions 
 
Information relating to the stability of the fermentation-derived intermediate, drug substance, or 
drug product should be provided. 
 
For general stability guidance, please refer to the following guidances:  CVM 5: Stability 
Guidelines and 73: Stability Testing Of New Veterinary Drug Substances And Medicinal 
Products, VICH GL3(R). 
 
With regard to intermediates, the recommendations for stability are more applicable to 
intermediates intended for re-sale but not generally otherwise.  A summary of the types 
of studies conducted, protocols used, and the results from the studies should be provided 
for fermentation-derived intermediates, drug substances, and drug products.  For 
intermediates and drug substances, conclusions regarding appropriate storage conditions 
and an appropriate retest or expiration date should be provided. For drug products, 
conclusions regarding the storage conditions and an appropriate expiration date should 
also be provided.   
 
1.  Batch Selection for Stability Studies 
 
For fermentation-derived intermediates, drug substances, and drug products, studies should be 
conducted on three separate batches, at least two of which are generated from different WCB 
vials.  These batches can be pilot scale.  However, the manufacturing process for the pilot-scale 
batches should fully represent and simulate the proposed full-scale production process. 
   
2.  Expiration Date versus Retest Date 
 
For fermentation-derived intermediates and drug substances, a retest period/date may be 
appropriate in cases where the fermentation-derived intermediate or drug substance shows little 
change in terms of potency loss and or/degradant increase throughout the proposed shelf life. 
                                                 
1 Storage conditions should be defined in accordance with the standard definitions for Freezer, Cold, or 
Controlled Room Temperature, provided in the USP.  When critical for maintaining the quality of the 
intermediate or drug substance, more specific numerical storage conditions should be used, rather than 
general terms (see USP General Chapter <1079>, Statements/Labeling of the Immediate Containers or 
Package Insert). 
 
 
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  Contains Nonbinding Recommendations 
 
 
In situations where there is a marked change or trend in the potency and/or degradation profile, 
such that there is a concern that an out-of-specification test result could occur during stability 
studies, an expiration date should be used.  When an expiration date is assigned to a fermentation-  
derived intermediate or drug substance, it means the material must not be used beyond that date 
and is to be discarded.  On the other hand, a retest date allows for use of a material beyond the 
retest date. 
 
A retest date is that date prior to which the material meets all applicable specifications.  Beyond 
that date, the material may be retested and, if acceptable, used within a reasonable amount of time 
(i.e., within 30 days).  The retest date should include those test attributes critical to the 
fermentation-derived intermediate or drug substance (e.g., potency, moisture content).  Expiration 
dates and retest dates should both be established based on supportive stability data. 
 
For fermentation-derived drug products, an expiration date should be established based on 
supportive stability data.  Retest dates are not appropriate for fermentation-derived drug products.  
 
3.  Postapproval Stability Protocol and Commitment 
 
For fermentation-derived intermediates, drug substances, and drug products, a postapproval 
stability protocol (on-going) and commitment should be provided. The sponsor should commit to 
place the first three full-scale production batches into the long-term stability program 
postapproval. In addition, a commitment to place a percentage of the total number of 
manufactured batches per year, with a minimum commitment to place at least one lot annually, 
should be provided. 
 
4.  Stability Data 
 
Appropriate stability data for the support of a retest or expiration date at the proposed storage 
conditions should be provided.  For the minimal filing requirements, consult CVM 73: Stability 
Testing Of New Veterinary Drug Substances And Medicinal Products, VICH GL3(R).   
 
 
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