GUIDELINE FOR SUBMITTING SUPPORTING

DOCUMENTATION IN DRUG APPLICATIONS FOR THE

MANUFACTURE OF DRUG SUBSTANCES

Center for Drug Evaluation and Research

Food and Drug Administration

Department of Health and Human Services

February 1987

For further information regarding the guideline please contact: 

Food and Drug Administration

Center for Drug Evaluation and Research

Office of Drug Evaluation I (HFD-100)

5600 Fishers Lane

Rockville, Maryland 20857

(301-443-4330)
TABLE OF CONTENTS

I. INTRODUCTION ................................................. 1

II. REQUIREMENTS FOR A NEW DRUG APPLICATION .................... 2

A. Physical and Chemical Characteristics ............................ 2

1. Properties ................................................ 2

2. Structure ................................................. 3

B. Stability .................................................... 4

C. Name and Address of the Manufacturer ........................... 4

D. Manufacture of the Drug Substance .............................. 4

1. Material Controls .......................................... 5

a. Starting materials ....................................... 5

(1) Definition of starting material ......................... 5

(2) Control procedures for starting materials ................ 7

b. Reagents, solvents, and auxiliary materials controls ............ 7

2. Synthetic Drug Substance ................................... 8

a. Flow chart of the synthesis ............................... 8

b. Description of the synthesis ............................... 8

c. Purification of the drug substance .......................... 10

d. Changes in the synthesis ................................. 10

3. Reference Standard ........................................ 13

4. In Situ Products (not isolated) ................................ 13

5. Microencapsulation ........................................ 13

6. Antibiotics and Other Drug Substances from Fermentation or Natural

Sources ................................................. 14

a. Fermentation .......................................... 14

(1) Control procedures for starting materials ............... 14

(2) Microbial identification, source, deposition .............. 15

(3) Fermentation process monitoring and control ............ 15

b. Extraction, isolation, analysis, characterization ............... 16

c. Drug substances obtained from plants and animals ............ 18

(1) Plants ........................................... 18

(2) Animals .......................................... 19

d. Semisynthetic antibiotics and other drug substances derived from

fermentation and natural sources .......................... 19
E. Process Controls ............................................. 20

1. Intermediates and In-process Controls ......................... 20

a. Pivotal intermediate(s) .................................. 22

b. Key intermediate(s) ..................................... 22

c. Final intermediate ...................................... 22

2. Reprocessing ............................................. 23

F. Drug Substance Controls ....................................... 25

1. Sampling ................................................ 25

2. Release Controls .......................................... 25

a. Appearance/description .................................. 25

b. Physical properties ..................................... 25

c. Specific identity test(s) .................................. 26

d. Impurity profile and limits ................................. 26

e. Assay ................................................ 28

3. Reference Standard ........................................ 28

G. Solid-State Drug Substance Forms: Relationship to Bioavailability ...... 31

1. Polymorphism ............................................. 32

2. Solvation (including hydration) ................................ 34

3. Particle Size (and surface area) ............................... 34

III. REQUIREMENTS FOR AN INVESTIGATIONAL NEW DRUG (IND) ......... 34

A. New Chemical Entity .......................................... 35

1. Phases 1 and 2 ........................................... 35

a. Physical and chemical characteristics ...................... 35

b. Manufacture of the new drug substance ..................... 36

c. Analytical methods ...................................... 36

2. Phase 3 ................................................. 36

a. Manufacture of the new drug substance ..................... 36

b. Analytical methods ...................................... 37

B. Known Chemical Entity ........................................ 37

1. Sponsor-Investigator Research Study (documentation on file) ....... 37

2. Sponsor-Investigator Research Study or Commercial Sponsor (no

documentation of file) ....................................... 39

IV. CURRENT GOOD MANUFACTURING PRACTICE REQUIREMENTS ........ 40

GLOSSARY ........................................................ 40

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GUIDELINE FOR SUBMITTING SUPPORTING DOCUMENTATION IN DRUG

APPLICATIONS FOR THE MANUFACTURE OF DRUG SUBSTANCES

I. INTRODUCTION

This guideline is intended to provide sponsors/applicants with procedures acceptable

to the agency for complying with regulations pertaining to the submission of adequate

information on the production and control of new drug substances. This guideline

addresses new drug substances manufactured by chemical synthesis, by fermentation,

or by isolation from natural sources (and combinations thereof); it does not cover drug

substances manufactured by recombinant DNA synthesis (biotechnology methods). 

The guideline does not impose mandatory requirements [21 CFR 10.90(b)]. It does,

however, offer guidance on acceptable approaches to meeting regulatory requirements. 

 Different approaches may be followed, but the applicant is encourage to discuss

significant variations in advance with FDA reviewers to preclude spending time and

effort in preparing a submission that FDA may later determine to be unacceptable.

The need to provide adequate information related to drug manufacturing is imposed in

section 505(b) of the Food, Drug, and Cosmetic Act, which requires a full description of

the "methods used in the manufacture of such drug." Such a

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 description includes the method of preparation of the drug substance, and the control

testing used to monitor its identity, strength, quality, and purity.

A description of the methods of preparation and process controls is pertinent not only

to a new drug application (NDA), but also to an abbreviated new drug application

(ANDA), an investigational new drug application (IND), and appropriate portions of a

drug master file (DMF).

For a new drug substance, a description of the "source and preparation" is a

requirement in the IND stage of study under 21 CFR Part 312. Subsequently, when an
Drug Substance Page 2

NDA is submitted, a description of the "methods used in the synthesis" are required

under 21 CFR 314.50(d) (1) (i).

Production of a drug substance, whether by synthesis, fermentation, or isolation,

usually starts with relatively impure or commercial grade (i.e, not of drug quality)

materials. Subsequent steps of the procedure involve preparation and transformation

of intermediates (with appropriate characterization and purification) to afford finally the

new drug substance. The quality and purity of the drug substance cannot be assured

solely by end-of-the-line testing, but depends on proper control of the manufacturing

and synthetic process as well. Proper control

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and attainment of minimal levels of impurities thus require the following: 

(a) appropriate quality and purity of the starting materials, reactants, and

reagents;

(b) establishment and use of in-process controls for intermediates;

(c) consistent adherence to validated process procedures;

(d) adequacy of the final (release) control testing of the new drug substance.

In addition to details of the manufacturing process and the in-process controls,

information is also needed concerning the final stages of purification (or

recrystallization) of the drug substance. Properties of the bulk new drug substance,

such as solubility, solid-state forms, particle size and surface area, may be critical for

the subsequent bioavailability and stability requirements of the final dosage form.

II. REQUIREMENTS FOR A NEW DRUG APPLICATION

II.A. Physical and Chemical Characteristics

II.A.1. Properties

The regulations require a full description of the physical and chemical

characteristics of the drug substance. This requirement may be satisfied by the

submission of information such as the following: name (generic name, chemical
Drug Substance Page 3

name, code number); Chemical Abstracts Service (CAS) number if available;

description (e.g., appearance, color, physical state); molecular formula and

molecular weight; structural formula (including ionic state if applicable);

stereochemistry (identifying chiral centers, cis-trans isomerism, etc.); enantiomer

or solid-state form ratios (e.g., for racemates, and for

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defined admixtures of isomers or enantiomers or solid-state forms); solubility

profile (aqueous and nonaqueous as applicable); partition coefficients; solution

pH; dissociation constant(s); melting or boiling point; refractive index; specific

gravity. For drug substances that are proteins, see the "CRC Handbook of

Biochemistry and Molecular Biology," "Methods in Enzymology," and related

monographs for how protein properties may be described.

The items above are not necessary or appropriate for all submissions. 

Additional information may be required, particularly as the state of the art

progresses.

II.A.2. Structure

The elucidation of structure (e.g., the data and its interpretation) should be based

on appropriate physical and chemical test results. These may include the

following: elemental analysis; mass spectrometry (MS); nuclear magnetic

resonance (NMR), ultraviolet (UV), and infrared (IR) spectroscopy; molecular

weight determination; stereochemistry and configurational or conformational

analysis (e.g., optical and geometric isomers); X-ray analysis; degradative

analysis (e.g., amino acid sequencing and/or analysis); chromatographic

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profile; other tests (e.g., functional group analysis, derivatization, complex

formation).
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Again, not all items are necessary or appropriate in all cases, and the listing

should not be considered limiting (i.e., more analysis may be required as the

state of the art progresses and the nature of the new drug substance demands). 

The actual data and the details of its interpretation should be placed in the

section for Reference Standard (see II.F.2, and 3.).

II.B. Stability

The regulations require a full description of the stability of the drug substance. See

the "Guideline for Submitting Documentation for the Stability of Human Drugs and

Biologics" for assistance in fulfilling this requirement.

II.C. Name and Address of the Manufacturer

The regulations require the application to contain the name and address of the

manufacturer. Each site should be properly identified by street address, city, and

State, and where appropriate the building number. If more than one building is

involved, the submission should state which part of the operation is conducted in

each building.

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III.D. Manufacture of the Drug Substance

There are two principal reasons for requesting a detailed presentation of the

synthetic pathway and/or manufacturing process. First, a particular synthetic

pathway will typically be uniquely associated with a set of impurities (actual and

potential), and also a specific solid-state form. The impurities may have significant

clinical or toxicological effects. It should be noted that (even in racemates)

enantiomers may be considered as impurities. Proper control of the synthetic

process monitors impurity levels during the process and in the final bulk drug

substance. When a change is made or proposed in a synthetic process, a different

ratio or even different set of impurities may arise, and the control testing may need
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modification. The "United States Pharmacopeia" (USP) also states that tests,

besides those provided in drug substance monographs, may be necessary when a

change in the source of material or processing occurs.

Second, knowledge of the synthetic pathway provides additional evidence to

support the proposed chemical structure. How the final drug substance molecule is

assembled from the starting material(s) and reactants, and descriptions of the

transformations performed in the steps of the synthesis, support the analytical

information elucidating the structure. For example, the final stereochemical

configuration may be related to that of the starting

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material, or may have been introduced by a stereospecific reaction or by resolution

of an intermediate in the synthesis. Knowledge of the synthetic pathway would

reveal which possibility is correct.

II.D.1. Material Controls

II.D.1.a. Starting materials

II.D.1.a.(1) Definition of starting material

What constitutes the "starting material" may not always be obvious. For

example, if a manufacturer carries out a simple final procedure, e.g., the

esterification of a carboxylic acid, to yield the drug substance, he may

consider the acid as the starting material. However, the full synthesis of

this acid may well be, and frequently is, quite lengthy and/or difficult; the

acid is thus not the actual starting material. Without reporting the full

synthesis of this acid from the actual starting material(s), the

manufacturer has not adequately described the synthetic process for

evaluation by FDA. The complete synthesis from the actual starting

material(s) should be submitted.
Drug Substance Page 6

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While a definition of starting material applicable to all situations cannot be

given, the following criteria for defining a starting material may be helpful: 

(a) It is incorporated into the new drug substance as an important

structural element.

(b) It is commercially available.

(c) It is a compound whose name, chemical structure, chemical and

physical characteristics and properties, and impurity profile are well

defined in the chemical literature (see Glossary).

(d) It is obtained by commonly known procedures (this applies

principally to starting materials extracted from plants and animals,

and to semisynthetic antibiotics).

Frequently, the starting material will meet several of these criteria. 

If it does not meet any, it is probably not the starting material. 

When an applicant wishes to use a starting material that is not

commercially available, the material should meet criterion (c). In

addition, for material that is not commercially

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available, it may be necessary to carry out more testing for impurities

than would be needed for a commercially available product.

The starting material may be the subject of a DMF (e.g., some

starting materials for semisynthetic antibiotics). When the starting

material is itself a drug substance, the synthesis of this material

should be provided either in full or by authorized reference to an

NDA or DMF. Generally the decision about what is the starting

material has been reached by agreement between the applicant and
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the FDA chemist before submission of the NDA (e.g., during an IND

End-of Phase 2 meeting, or pre-NDA meeting).

II.D.1.a.(2) Control procedures for starting materials

Starting materials should be listed. Acceptance specifications and tests

defining identity, quality, and purity should be provided. The analytical

test methods should be briefly described. The source of the starting

material need not be identified, but may be requested.

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A specific identity test should be performed, as well as an assay, with

limits for impurities. In those cases where impurities (e.g., positional

isomers of aromatic compounds) could be carried through to the drug

substance, a purity profile should be provided (e.g., chromatography with

quantitation/identification of impurities). Assurances or statements of

quality from the supplier are acceptable for the profile, provided that the

manufacturer establishes the reliability of the supplier's analyses through

validation, initially and at appropriate intervals. These statements from

suppliers should include specifications and results and should indicate

the type of method used for analyses.

II.D.1.b. Reagents, solvents, and auxiliary materials controls

These chemicals should also be listed. The specifications and test methods

for each such material should be stated, and/or a statement of quality

provided. The applicant should describe the specific identity test performed

(unless omitting such a test has been otherwise justified, e.g., because of

hazard). The extent of additional testing performed -- whether
Drug Substance Page 8

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by the supplier or by the applicant -- should be based on the role of the

chemical in the synthesis. For example: a base (e.g., sodium hydroxide)

used to neutralize excess acid in a synthetic reaction mixture would not

normally require extensive purity testing; in contrast, an optically active

organic acid used in a resolution step (e.g., one enantiomer of

dibenzoyltartaric acid) would require such additional testing.

II.D.2. Synthetic Drug Substance

An applicant should provide complete information on the synthesis, from starting

material(s) to the bulk new drug substance. The description should contain a

diagrammatic flow chart of the whole synthesis and a written statement for each

step of the synthesis.

II.D.2.a. Flow chart of the synthesis.

The flow chart typically should contain the following: 

(1) Chemical structures of reactants (i.e., starting materials and

intermediates, and also molecules incorporated into the structure) and

products;

(2) Stereochemical configurations, where applicable; 

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(3) Intermediates (either in situ or isolated); 

(4) Solvents, catalysts, and reagents; 

A ratio or mixture of products (e.g., two or more isomers) produced by a

reaction should be shown in the flow chart. Significant side products and

impurities, particularly those that interfere with the analytical procedures

or are toxic, should be illustrated separately (see sections II.D.2.c. and

II.F.3.).
Drug Substance Page 9

II.D.2.b. Description of the synthesis

The written statement for each step of the synthesis, with greater detail

included toward the final steps of the process, should include the following: 

(1) Typical equipment used for the reaction; 

(2) Reactants (starting material or intermediate used in the step, with

chemical names and amounts); 

(3) Solvents, catalysts, and reagents (chemical names and amounts);

(4) Conditions (temperature, pH, time, pressure, etc.); 

(5) Tests for completion of reaction, if employed; 

(6) Workup and isolation procedures;

(7) Purification procedures for drug substance and for intermediates, if

employed;

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(8) Yield ranges (crude and/or purified; weight and percent).

The final step of the synthesis and the isolation of the crude new drug

substance, as well as its purification, should be provided in full detail. (See

section II.D.2.c below regarding purification of the drug substance.) 

Besides providing a written description of the synthesis which includes

verified ranges for the operating parameters (refer to section II-E [Process

Controls] and section IV [CGMP]) and for the expected yield, the applicant

should provide a written example of actual practice, clearly identified as an

example for the reviewer's information. This example should not be merely a

copy of batch records but should contain more detail.

Any alternate method or permissible variation that may be employed (e.g.,

alternate starting materials, reactants, solvents, conditions, catalysts,

isolation, and/or purification procedures) should be reported. Comparative
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analytical data for the material produced by each variant synthetic method

should be provided.

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II.D.2.c. Purification of the drug substance

The description of the purification of the crude new drug substance and its

isolation from the final reaction step mixture should be given in detail, and

should include: 

(1) The yield ranges of the crude product; 

(2) Any tests performed on the crude product to determine its purity (see

item 6, below);

(3) A detailed description of the isolation and purification procedures

(e.g., for recrystallization: the solvent used, the quantity of solvent in

relation to the amount of crude product, whether it is filtered while hot,

whether a decolorizing agent is used, the rate of cooling and the final

temperature, the use or re-use of any mother liquors, and if second crops

are obtained);

(4) Alternative purification procedures (see the last paragraph of section

II.D.2.b.; see also section II.G.);

(5) The yield range (weight and percent) of the purified product;

(6) Evidence demonstrating that the purification procedure improves the

purity, such as before-and-after chromatographic illustrations.

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This testing and information may be necessary only on initial production

batches, once the purification process has been verified or validated.

II.D.2.d. Changes in the synthesis

Proposed changes in the synthesis should be submitted to the application as

a supplement for an approved NDA or as an amendment to an IND, a DMF, or

a pending NDA. An approved supplement is required [21 CFR 314.70(b) (1)
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(iv)] to change the method of synthesis approved in the NDA for the drug

substance, including a change in solvents.

When the route of synthesis is changed (i.e., reactions and/or intermediates

are different from those approved in the NDA), comparative analytical data

(i.e., a complete purity profile) for the drug substance made by each route

should be provided. A special case, where the proposed change is to

redefine the starting material, is discussed below.

When there is a change in the solvent used for the final crystallization of the

new drug substance, the new drug substance should be examined for

changes in crystalline form and/or solvation; refer to

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section II.G. The new drug substance must meet its original specifications for

crystalline form and/or solvation.

Solvent changes for other reaction steps or purifications also require a

supplemental application. The application should contain evidence that the

change affords material (compound or intermediate) of equivalent quality and

purity, but morphology need not be considered.

An approved supplement is required (21 CFR 314.70(b) (1)) if an applicant

wants to shorten the synthesis approved in the NDA or develop a new

synthetic method by redefining the starting material, in order to employ a

compound later in the synthesis that has become commercially available. 

This compound must have been an intermediate in the approved NDA

synthesis, and must meet both the "b" and "c" criteria for starting material. 

The compound should be used at least two full steps before the new drug

substance if possible (i.e., it should be prior to the final intermediate). 
Drug Substance Page 12

Additional information on the characterization and purity profile of the starting

material may be needed, depending on the adequacy of the literature

references cited (copies should be provided). For

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compounds cited in journal articles, an elaboration of the published material

(i.e., additional information about testing for impurities) may suffice. For

compounds described in patents, both complete characterization and a full

purity profile will usually be needed. Analytical test procedures used to

qualify each new source/supplier of the new starting material should be

described. A general testing protocol may be suitable.

The applicant should demonstrate by direct comparison (i.e., both by analyses

and by a use test) that the compound is equivalent to the material used to

make the new drug substance employed in the clinical trials, and that the

acceptance tests and specifications for the compound are adequate. The

use test should be at least on a pilot scale (i.e., larger than bench scale).

A commitment to submit results from thorough examination of the first three

full-scale batches made with the material should be provided. The

examination should be similar in scope and extent to the testing involved in

qualifying a new reference standard. For changes of the type

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 permitted by 21 CFR 314.70(c) (3), an adequate synthesis description on file

would facilitate a conclusion that changes in site of manufacture of the new

drug substance do not require prior FDA approval for implementation.
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II.D.3. Reference Standard

The original application should include a full description of the preparation of any

reference standard substance used, including the description of the purification

steps. See also section II.F.3.

II.D.4. In Situ Products (not isolated)

An in situ product is formed when the synthesis of the drug substance and the

manufacture of the final product are carried out in the same operation, usually in

solution. Examples are: lithium citrate syrup prepared from the in situ reaction of

lithium hydroxide and citric acid, and lidocaine hydrochloride prepared in situ

from a solution of lidocaine base and hydrochloric acid.

The description of the manufacture of an in situ product should be treated as for

any other synthetic step (i.e., full descriptions of how the materials

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employed are prepared should be given). While purification procedures and

yield range information are not needed, successful formation of the desired

product should be demonstrated.

II.D.5. Microencapsulation

Microencapsulation is a process in which small, discrete solid materials, liquid

droplets, or gases are completely enveloped by an intact membrane. The

functions of the capsular membrane are to protect the enclosed material and/or to

control the flow of materials, inside and outside, across the membrane. The

membrane may consist of an inert polymeric material (e.g., ethylcellulose, gelatin,

polyvinyl alcohol, etc.). Depending on the desired characteristics, a wide range

of film thicknesses may be employed. A microcapsule may be free, consisting of

a single particle, or it may be in the form of clusters of particles.
Drug Substance Page 14

The manufacture of a microencapsulated drug substance is considered an

extension of the synthesis or manufacturing process for the drug substance itself. 

 Consequently, the same complete description should be submitted as for any

other step. In addition, any special treatment or precautions involved in

preparation and handling of the microencapsulated drug substance should be

described.

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II.D.6. Antibiotics and Other Drug Substances from Fermentation or Natural

Sources

II.D.6.a. Fermentation

II.D.6.a.(1) Control procedures for starting materials 

Fermentation processes use well-characterized microorganisms to

convert by biosynthetic reactions, various sources of carbon, nitrogen,

oxygen, etc., into antibiotics or other desired chemical substances. 

Biosynthetic control mechanisms, such as catabolite repression and

substrate induction, which can affect yields and products mixes, may

depend on the type of raw material used. An evaluation of a fermentation

process thus begins with consideration of the starting materials. Starting

materials (and any alternatives) should be listed and their specifications

and (where applicable) degree of purity provided, with a brief description

of the test methods. Special attention should be given to specifications

for organic materials used in fermentations (e.g., starch, glucose, lactose,

corn steep liquor, soy bean meal). Inorganic components used in

fermentations should meet the same requirements as for chemical

syntheses. When 

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precursors or inducers are used, their specifications and tests should be

provided.
Drug Substance Page 15

II.D.6.a.(2) Microbial identification, source, deposition 

The most critical factor in any fermentation process is the specific

microorganism cultured. Therefore, proper strain identification should be

performed according to known methods (e.g., "Bergey's Manual of

Determinative Bacteriology"). The description of microbial identification

should include morphological, cultural, and biochemical characteristics

(e.g., cell shapes, size, appearance on the agar medium, utilization of

various carbon and nitrogen sources, temperature for optimal growth,

aerobic or anaerobic conditions).

The source of the original microbial isolate (soil, water, air, etc.) should be

described, and strain improvement procedures (e.g., mutation or genetic

engineering techniques) should be briefly described. If any microbial

isolate of the producing organism has

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been sent to official culture collection organizations, the organization

(e.g., American Type Culture Collection (ATCC); United States

Department of Agriculture, Northern Regional Research Laboratory

(NRRL) and its identification number should be provided in the

application.

II.D.6.a.(3) Fermentation process monitoring and control 

Antibiotic production in large-volume fermenters, and other microbial

transformations, can be divided into three successive stages: 

(a) media preparation and sterilization;

(b) fermenter inoculation; and;

(c) fermentation itself.

Each step should be briefly described or characterized.
Drug Substance Page 16

The description of media preparation should include: detailed media

composition (i.e., the starting materials, precursors, etc. used); the

method of media sterilization (e.g., directly in the fermenter or through a

continous sterilization system); the temperature and duration of

sterilization; and the pH of the medium after sterilization.

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A brief description of the fermenter inoculation should be included.

The description of the fermentation stage should include those

parameters which are routinely monitored for the control of that

fermentation: e.g., duration, temperature, pH, aeration rate (volume of air

per volume of medium), concentration of dissolved oxygen, amount of

reducing sugar, ammonium concentration. The critical in-process

controls should be indicated. If an antifoaming agent is used, its identity

and concentration should be provided.

II.D.6.b. Extraction, isolation, analysis, characterization 

At the end of the fermentation the amount of antibiotic or other drug substance

present in the fermentation broth should be determined; the analytical

procedure used should be described (see below). The description of the

isolation and purification procedure should include both a diagrammatic flow

chart and a written statement. The flow chart 

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should include the solvents (and/or reagents) used for each step and should

give the purity (percent) of the product after each step. Conditions (e.g.,

temperature, pH) may be included.
Drug Substance Page 17

The written statement should include the following information for each step,

where applicable: 

(1) Method of isolation and purification; 

(2) Procedure for precipitation (e.g., isoelectric, salting out, solvent

addition);

(3) Equipment;

(4) Solvents and reagents;

(5) Conditions (temperatures, pH, time); 

(6) Yields.

Analytical technique(s) should be adequate for identification and quantitation

of side products and impurities in the final bulk preparation, as well as for

following the progress of purification. Once it has been shown that the

isolation and purification procedure does (largely, and successively) remove

side products and impurities, less sophisticated (i.e., less discriminating)

methods may be used to routinely monitor the progress of isolation and

purification.

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The purified fermentation product should be completely characterized and (if

possible) its structure determined. The characterization information should

be comparable in extent and detail to that for a totally synthetic drug

substance and should also include examination for solid-state forms (see

sections II.F. and G.). Those specific analytical techniques which

differentiate the product from related antibiotics should be described.

Minor active components of an antibiotic mixture should be identified and

individually quantitated. In the case of an antibiotic preparation with several

major active components, limits for each of these should be proposed based
Drug Substance Page 18

on their pharmacological and toxicological properties. Side products and

impurities should be examined for toxicological properties, using either the

final bulk preparation (containing the side products and impurities at the

proposed limits) or the individually isolated material(s). (See Section

II.F.2.d.) 

II.D.6.c. Drug substances obtained from plants and animals 

II.D.6.c.(1) Plants

The description of the collection and preparation should include the

botanical species and the part of the plant. Other factors which 

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influence the quality or composition of the final product should be

described. These factors may include the following: 

(a) Geographical location where the plant is grown; 

(b) Storage and transportation conditions; 

(c) Drying conditions;

(d) Grinding conditions.

The description of the collection and preparation procedure should

include the test method(s) for identity and assay for the drug substance in

the original and crude material(s). Typical results should be provided. 

The description of the extraction and isolation procedures should include

the same information, where applicable, as for antibiotics or fermentation

products (section II.6.b.), with similar attention devoted to identification of

impurities and minor components, and to the characterization of the

material (including elucidation of structure).
Drug Substance Page 19

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II.D.6.c.(2) Animals

The description of the collection and preparation procedure should, where

applicable, include: 

(a) Species, and organ or tissue used; 

(b) Statement(s) demonstrating compliance with USDA or

equivalent requirements or regulations; 

(c) Conditions for storage and transport of the organ or tissue to the

processing facility; 

(d) Drying conditions;

(e) Grinding procedure.

The description should include the test method(s) for identity and assay

for the drug substance in crude materials(s), and typical results should be

provided. The extraction and isolation procedure descriptions should

include, where applicable, the same information as requested for

antibiotics or fermentation products (section II.6.b.), and similar attention

should be given to identification of impurities and minor components, and

to characterization of the material (including elucidation of structure).

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II.D.6.d. Semisynthetic antibiotics and other drug substances derived from

fermentation and natural sources 

The starting material for a semisynthetic antibiotic, or other drug substance

derived from natural sources, is obtained by fermentation and/or extraction. 

The description of the starting material manufacture should be provided as

indicated previously (section II.D.6.a,b,c) or by reference to a DMF as

indicated in section II.D.1.a. The information for the synthesis of the final

drug substance from this starting material should be provided as described in

section II.D.2.
Drug Substance Page 20

Precautions, including animal safety testing when appropriate, to detect,

identify, and eliminate impurities (present in the naturally derived starting

material or formed in subsequent chemical transformations) from the final

product should be described.

Some of the transformations may be enzymatically catalyzed. In such cases

the following information should be provided:

(1) Biological source of the enzyme;

(2) descriptive technical name of the enzyme;

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(3) descriptive information on the enzyme preparation, akin to that

requested for chemical reagents (see section II.D.2.b.).

II.E. Process Controls

II.E.1. Intermediates and In-process Controls

The regulations require that controls (specifications and tests) be employed at

selected intermediate stages of the synthetic process to assure that the synthetic

and purification procedures are operating properly and that the intermediate

tested is suitable for subsequent processing. The choice of which

intermediate(s) or steps in the process to test, and the kind of testing required,

are the responsibility of the applicant based on his experience during the

development and verification of the total synthetic process. In early development

work, every step would usually have been examined (at least for extent of

reaction) and every intermediate at least partially characterized with some

estimate of purity. As experience is gained with the synthesis, the critical

reaction steps and intermediates to be monitored are selected. At the time of

NDA submission, in-process control points should have been selected and
Drug Substance Page 21

appropriate specifications and tests established to meet the requirements of the

regulations. This whole operation is part of the 

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process validation of the synthesis.

The basis for selecting control points and intermediates should be explained, and

the adequacy of the specifications and tests to control the synthetic process

demonstrated. The ranges for the operating parameters in the written

description of the synthesis should be chosen in light of the controls

(specifications and tests). Generally, broad operating ranges will require stricter

controls. (See also section II.E.b. (recovery and rework) below.) With additional

experience subsequent to NDA approval, the choice and nature of in-process

control procedures may require modification. Changes in in-process control

procedures will require additional validation (see section IV).

Controls may be designed to 

(a) demonstrate that the desired product has been obtained;

(b) determine a key physical property (e.g., melting point, optical rotation,

etc.);

(c) determine purity/impurity of the intermediate;

(d) determine that the yield is within the normal operating range.

In some cases no controls for the intermediate may be feasible (e.g.,

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where they are held in solution, or are directly processed to the next compound). 

When appropriate, testing may consist only of a test designed to monitor the

progress of the synthesis (i.e., reaction completion).
Drug Substance Page 22

Some or all of the above kinds of process controls should be met at each point

selected for in-process control testing. Pivotal, key, and final intermediates (see

Glossary, and below) would ordinarily require at least the in-process controls

listed above. To eliminate the need for heroic final cleanups, it is expected that

the degree of purity of intermediates will increase progressively, from the first

intermediate on to the drug substance itself.

II.E.1.a. Pivotal intermediate(s) (See Glossary.) 

Any pivotal intermediate should be described in adequate detail (i.e., be well

characterized) and be subject to rigorous examination procedures as part of

the specifications and tests, including thorough chromatographic examination

so as to avoid overlooking impurities arising from alternative syntheses. 

Such rigorous examination need not be routine but may be needed in special

circumstances such as when the supplier or synthesis is changed. The

degree of testing and the level of purity required for a

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pivotal intermediate should increase as its position in the synthesis scheme

approaches the final intermediate.

II.E.1.b. Key intermediate(s) (See Glossary.)

The specifications should be adequate to assure that the molecular

architecture necessary for the final product, as well as the requisite degree of

purity, have been attained. Test procedures should thus show that the

desired transformation (such as introduction of chirality, or a stereospecific

reaction) has occured in the manner expected and within the normal yield

range expected, and show by quantitative determination(s) that undesired

materials (e.g., isomers, by-products, starting materials) are within established

limits.
Drug Substance Page 23

II.E.1.c. Final intermediate (see Glossary.)

Specifications and tests for final intermediate should be nearly as extensive

and stringent as those for the new drug substance itself, because this is the

last opportunity to monitor purity and impurities before the final reaction.

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II.E.2. Reprocessing

Intermediates which do not meet in-process specifications may be further purified

using the same purification procedure described in the NDA. When an alternate

purification procedure is used, the recovered material should be subjected to the

same final processing operation and the same testing as for the first time.

FDA recognizes that operating conditions (such as time and temperature)

occasionally deviate from the NDA description. A protocol should be provided

for the procedure which will be used to qualify the batch of intermediate or drug

substance as meeting specifications when reaction conditions or operating

parameters fall outside the typical/normal range (i.e., "excursions," or minor

deviations). The protocol should describe the additional analytical testing which

will be used in qualification of the batch. The testing should be more extensive

than required by routine specifications and tests and may include, as appropriate,

the use of nonregulatory analytical methods. For example, batches of new drug

substance in this category (i.e, when reaction conditions are outside the norm)

should be examined by discerning analytical procedures such as those used for

Reference Standard qualification.

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In-process control procedures should be established and described for the

handling of mother liquors and recovery of second crops when this is done; see

section II.D.3.d. While the re-use of mother liquors and recovery of second

crops may be common/normal practice and is acceptable from a CGMP

viewpoint, it is not necessarily acceptable (i.e., when impurity levels build up),
Drug Substance Page 24

and extensive recycling of mother liquors or repeated recoveries of additional

crops is discouraged (refer to section IV (CGMP) and the "Guideline for

Inspection of Bulk Pharmaceutical Chemical Manufacture" in this regard.) The

recovery procedures should be included in batch production records.

Provision should be made in the NDA for the typical and usual reprocess

procedure for drug substance which fails to meet specifications, usually by one or

more additional recrystallizations from the final solvent. Extraordinary analytical

examination is not required in this case.

A single batch of drug substance which fails to meet specifications may be

purified by an appropriate procedure and then processed by the same final

purification procedure described in the NDA, provided that the purity of the

reprocessed material being so treated in the final purification step is as good as

the normal drug substance at this stage of processing.

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Some types of bulk drug substance for salvage (e.g., accumulated unused

analytical samples, unused portions of lots, bulk returned from customers) may

be processed in this fashion.

Such reworked drug substance batches should be subjected to additional

analytical examination, as indicated above (i.e., for drug substance resulting from

minor deviations of process conditions). The rework operation, and the reason

for it, should be documented. The blending of batches or lots for the purpose of

salvaging unsatisfactory batches, without subsequent additional purification by

an appropriate procedure and processing by the final purification step described

in the NDA, is not permitted under current guidelines.
Drug Substance Page 25

If not part of the original NDA, a supplement should be submitted to the NDA

when a standard (validated) reprocessing procedure for unsatisfactory bulk drug

substance is to be routinely employed; refer to the "Guide to Inspection of Bulk

Pharmaceutical Chemical Manufacturing."

When drug substance is to be recovered from dosage forms, reference

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should also be made to the "Guideline for Submitting Documentation for the

Manufacture of and Controls for Drug Products." This type of operation will

require a supplement.

II.F. Drug Substance Controls

The regulations require specifications and analytical methods (i.e., release controls

for the new drug substance) to help assure that the proper identity, strength, quality,

and purity of the drug substance have been attained and are consistent from batch

to batch. The following information should be submitted to define these

specifications and test methods:

II.F.1. Sampling

Sampling requirements are covered by CGMP regulations (see section IV). The

sampling plan should be described, giving the basis for the plan; it should satisfy

appropriate statistical considerations.

II.F.2. Release Controls

Examples of specifications and tests that may be applicable are as follows:

II.F.2.a. Appearance/description

II.F.2.b. Physical properties (e.g., melting range, specific rotation, refractive

index, crystalline form, particle size).
Drug Substance Page 26

For drug substances with chiral centers or other configurational requirements,

the specifications and tests should assure that material

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(whether a single enantiomer or isomer, a racemate, or a known ratio of

isomers) with the requisite properties for therapeutic activity has been

produced. See section III in this regard.

Similarly, when the solid-state properties (see section II.G.) of the new drug

substance, such as polymorphism or particle size, are known to affect

physiological or pharmacological activity (i.e, bioavailability of the drug

product), the specifications and tests should provide appropriate limits for

these properties (whether as single forms or as admixtures).

II.F.2.c. Specific identity test(s) (i.e., infrared (IR), nuclear magnetic

resonance (NMR), and mass spectrometry (MS)).

The specific identity test(s) should be capable of distinguishing the new drug

substance from related compounds. If only one specific identity test is

performed, an IR spectrum (KBr pellet) is preferred. Other identity tests

(such as UV spectra, or relative mobility [R[f] or T[R] values] by various

chromatographic methods) are considered confirmatory rather than specific. 

Doing additional (confirmatory) tests is encouraged; however, doing several

confirmatory tests will not substitute for a specific identity test.

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II.F.2.d. Impurity profile and limits (i.e., tests to detect, identify, and quantitate

the presence of starting materials and intermediates, by-products,

degradation products, solvents, and other impurities, as well as

proposed/recommended limits for such impurities).

Impurities should not only be detected and quantitated, but should also be

identified and characterized when this is possible with reasonable effort. 
Drug Substance Page 27

During the development and validation of the analytical methods the following

concerns should be addressed: 

(1) Ability of the method to detect and resolve impurities (i.e., the

sensitivity and specificity of the methods);

(2) Quantitation, and linearity of response; 

(3) nature of the impurity (e.g., starting material, intermediate,

degradation product);

(4) classification (e.g., major or minor, toxic, known or unknown [i.e., not

yet chemically identified or characterized]);

(5) isolation, purification, and proof of structure (i.e., identification and

characterization), including the preparation of authentic specimens

for comparison when needed.

The section on impurities in the application should demonstrate that all the

above points have been considered (i.e., that the examination of

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the new drug substance for impurities has been adequate, and that

reasonable efforts have been made to fully identify and/or characterize them). 

Structures of known impurities, and validation of the analytical methods,

should be provided (following the Specifications and Tests) and be referenced

in section II.F.3. (Reference Standard).

All major impurities should be individually limited. The maximum amount per

unit does of every individual impurity should be provided. If there is

information on toxicity or information on toxic limits that have been set for

these impurities, this information should be provided.

A summary tabulation of the results from the analytical examination of

individual batches of the drug substance used in animal and clinical testing,
Drug Substance Page 28

listing all impurities (individually as well as total, and including those which

are unidentified), should be provided.

II.F.2.e. Assay

The assay for the drug substance should be specific if possible, since it can

then be used for stability-indicating purposes. It may be practical

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to measure the drug substance and impurities by the same procedure (e.g.,

high pressure liquid chromatography (HPLC)). Since a specific identity test is

required, assay specificity is not essential when impurities which might

interfere are controlled (and limited) by suitable (e.g., chromatographic)

methods; in these circumstances non-specific assay methods, such as a

potentiometric titration, may be employed. The assay limits established in

the NDA for the new drug substance, as well as the limits for impurities,

should be based on actual manufacturing results (i.e., from analyses of

individual batches). A retest date, based on the stability of the compound

under actual storage conditions, is desirable.

Microencapsulated compounds should also be tested for particle size and

dissolution rate. Not included in this listing, but generally provided as part of

the specifications and tests, are 

(1) moisture content or loss on drying;

(2) residue on ignition;

(3) residual solvents;

(4) heavy metals.

The specifications should provide a reasonable material balance.

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II.F.3. Reference Standard (See Glossary.)
Drug Substance Page 29

The reference standard can be defined as drug substance of the highest purity

reasonably attainable, specifically prepared by independent synthesis or by

(further) purification of existing production material, and shown to be authentic

material by an extensive set of analytical tests. It is usually used for the

structure elucidation work. If the synthesis differs from that in the application, full

details should be provided. Any additional purification procedure should be

described (see II.D.3.). The reference standard substance is maintained by the

applicant as the standard (benchmark) against which working standards are

judged.

A working standard is defined as that reference material of known purity used for

routine analytical comparison of clinical or production batches of the drug

substance and/or drug product.

The analytical testing needed to document the suitability of reference standards

is generally more extensive than that required by the bulk drug substance

specifications. Appropriate testing procedures may include, where applicable:

elemental analysis; various chromatographic methods

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(e.g., thin layer chromatography (TLC, and HPTLC), high pressure liquid

chromatography (HPLC), gas-liquid chromatography (GLC), affinity

chromatography, and size exclusion chromatography); infrared (IR) and

ultraviolet (UV) spectra; nuclear magnetic resonance spectra (NMR; usually

[1]H-NMR and [13]C-NMR); mass spectrometry (MS); specific rotation (and also

optical rotatory dispersion (ORD) and circular dichroism (CD)); X-ray

crystallography; phase solubility analysis; thermal analysis methods (e.g.,

differential scanning calorimetry (DSC), differential thermal analysis (DTA), and

thermogravimetric analysis (TGA)); various methods of radioimmunoassay (RIA);

electrophoresis; and bioassay procedures.
Drug Substance Page 30

The structures of known impurities (e.g., starting materials, process impurities,

degradation products) should be shown. The levels of all impurities found

(including those not chemically identified, isolated, and characterized) should be

provided as a summary tabulation. The validity (i.e., accuracy, precision,

sensitivity, specificity) of the analytical methods used for purity determination

should be demonstrated. The preparation and characterization of impurity

reference standard materials (which are to be submitted for use in methods

validation) should also be described. This

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information may be provided following the section on Specifications and Tests for

the new drug substance and referenced in the Reference Standard section.

The data provided in the Reference Standard section for the current batch of a

reference standard should include a certificate of test results. Copies of original

data (e.g., spectra and chromatograms) from the examination of the reference

standard substance, as well as details of interpretation, should be provided.

When the new drug substance has specifications and tests for solid-state form(s)

(see section II.G.), the methods for these determinations should be described

and the results provided. Reference standards of forms excluded by the

specifications, and information on their manufacture and analyses, may be

requested.

For replacement batches of reference standards, a certificate of analysis and

summary of the analytical profile should be provided demonstrating their

suitability for use. (See also the data requirements for samples for methods

validation in the "Guideline for Submitting Samples and Analytical Data for

Methods Validation" and in 21 CFR 314.50(e) (2) (i)).

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Drug Substance Page 31

Since reference standards are essential to testing the bulk substance, their integrity

should be safeguarded by proper storage and their stability monitored by periodic

examination.

II.G. Solid-State Drug Substance Forms: Relationship to Bioavailability

The regulations require, where appropriate, specifications characterizing the drug

substance so as to assure the bioavailability of the drug product (see 21 CFR

314.50(3) (ii), and 320.52(e)[4-1-85 edition]). Certain solid-state properties of the

drug substance (e.g., polymorphic form or amorphism, solvation or hydration,

various types of inclusion complexes, and particle size or surface area) may

profoundly affect dissolution and bioavailability from solid dosage forms or

suspension drug products. These properties are less important for solution dosage

forms and for drug substances which are highly water soluble.

For drug substances with limited aqueous solubility (e.g., griseofulvin,

nitrofurantoin), particle size can have a large effect on the behavior of the drug

product, and significant differences in particle size may also affect toxicity.

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Identifying, characterizing, and controlling the differences in solid-state forms is

especially important when a bioavailability problem exists and/or the drug substance

is obtained from multiple sources.

By the time of an NDA submission, the applicant should have established whether

(or not) the drug substance exists in multiple solid-state forms, whether these affect

the dissolution and bioavailability of the drug product, and whether particle size is

important for dissolution and bioavailability of the drug product. It is not necessary

to `create' additional solid-state forms by techniques or conditions irrelevant to the

synthetic process.
Drug Substance Page 32
Drug Substance Page 33

The applicant should provide information describing how and why it has been

concluded that

(a) a change in solid-state form does not occur when the drug substance is

manufactured and stored according to the NDA directions; or

(b) different forms occur but do not result in a bioavailability problem; or

(c) polymorphism, solvation, or particle size has an important effect on

bioavailability.

The test methods used should be briefly described and be shown to be suitable. In

cases (a) and (b), suitability means that the procedure(s) can, with reasonable

certainty, detect and distinguish between polymorphs (or solvates) should they

occur. For case (c), suitability means that the procedure(s) can detect and

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quantitate polymorphs and/or solvates in admixtures of such forms, or measure

particle size.

Appropriate manufacturing and control procedures (including in-process testing

when needed) should be established for the production of the desired solid-state

form(s). It should be emphasized that the manufacturing process (or storage

condition) is responsible for producing particular polymorphs or solvates; the control

methods merely determine the outcome.

While specific kinds of differences in solid-state forms are considered separately

below, there is some interdependence; thus comparisons should, if possible, be

performed on samples of similar particle size.

II.G.1. Polymorphism

Some drug substances exist in several different crystalline forms ("polymorphs"),

due to a different arrangement of molecules in the crystal lattice, which thus show

distinct differences in their physical properties. The same drug substance may
Drug Substance Page 34

also exist in a noncrystalline (amorphous) form. These various forms differ in

their thermodynamic energy content, but not in composition. One of the critical

factors affecting polymorphism (or solvation) is the choice of final solvent and

isolation conditions in the synthesis. As noted previously (II.D.2.d.),

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when a change is made in the final crystallization solvent, evidence must be

provided that no transformation in solid-state form has occurred. Routine

storage conditions, as well as some conditions of product manufacture (e.g.,

tablet compression, or use of an organic solvent during granulation) may also

cause transformations. The question is: Is the crystalline (or amorphous) form

stable, or is it time and/or process dependent? 

Appropriate analytical procedures should be used to determine whether (or not)

polymorphism occurs. Some examples of physico-chemical measurements and

techniques are

(1) melting point (including hot-stage microscopy);

(2) infrared spectra (not in solution);

(3) X-ray powder diffraction;

(4) thermal analysis methods (e.g., differential scanning calorimetry (DSC),

differential thermal analysis (DTA), thermogravimetric analysis (TGA));

(5) Raman spectroscopy;

(6) comparative intrinsic dissolution rate;

(7) scanning electron microscopy (SEM).

These methods are not ranked in order of their discriminating or quantitating

ability. It is the applicant's responsibility to select the method(s) used to 

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provide evidence concerning polymorphism, and if bioavailability is affected, to

provide and demonstrate the suitability of the specifications and tests (including
Drug Substance Page 35

preparation and provision of reference standards) for the control of the solid-state

form of the drug substance.

II.G.2. Solvation (including hydration)

Conditions used in manufacture and/or storage of the drug substance may result

in the isolation or formation of a solvated or hydrated drug substance. This is

most directly assessed by testing for loss on drying (LOD) or by Karl Fischer

titration (for hydrates). Information from other methods (e.g., TGA) may be

necessary, because some solvates are known to be stable at temperatures above

the boiling point of the solvent. When solvation or hydration affects

bioavailability, appropriate manufacturing and control procedures should be

established.

II.G.3. Particle Size (and surface area)

Particle size distribution and surface area of the drug substance may affect the

dissolution and bioavailability of the drug product. Therefore, an applicant may

conduct operations to alter particle size/surface area

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 in order to achieve more favorable properties for the drug substance. For drug

substances with low aqueous solubility (e.g., less than 5 milligrams per milliliter)

both the typical original particle size distribution and the particle size distribution

after any alteration procedures should be presented (preferably graphically), with

detection limits indicated. The effect of drug substance particle size on

dissolution (of the drug product) should also be provided. When particle

size/surface area of the drug substance is relevant to the bioavailability of the

drug product, the description of the procedure(s) used to alter particle

size/surface area and the methods used for examination should be provided, and

appropriate specifications and tests established for control.
Drug Substance Page 36

III. REQUIREMENTS FOR AN INVESTIGATIONAL NEW DRUG (IND) 

Present Regulations (21 CFR Part 312) require the submission of manufacturing and

controls information for the new drug substance along with the name and address of

the manufacturer. Depending on the type of IND and the phase of investigation(s),

information should be submitted as described below.

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III.A. New Chemical Entity (see Glossary)

III.A.1. Phases 1 and 2

III.A.1.a. Physical and chemical characteristics 

The description of the physical and chemical characteristics of the new drug

substance (NDS) should include, where applicable, such properties as:

appearance, solubility profile, pH/pK, melting point, specific gravity, optical

rotation, refractive index, and molecular weight. See also section II.A.1, and

2.

When the NDS is asymmetric (e.g., contains one or more chiral centers, or

has cis-trans or other types of isomers), the sponsor should ideally (and prior

to the submission of an IND) have either separated the various potential

stereoisomers of the NDS or synthesized them independently. 

Physical/chemical information about each stereoisomer should be provided (in

detail), or may be requested. Individual stereoisomers may need to be

studied for pharmacological and toxicological properties (and/or for safety and

efficacy).

Appropriate specifications and tests to control the ratios of any admixtures

(e.g., ratios of enantiomers, and/or solid-state forms) for batches of drug

substance used in toxicological and/or clinical studies

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Drug Substance Page 37

should be established, so that results can be extrapolated to the drug

substance proposed for marketing.

III.A.1.b. Manufacture of the new drug substance (NDS) 

A description of the preparation of the NDS (including antibiotics) should

include the synthesis, isolation and/or extraction, and purification. This

normally should include a flow chart (giving structural formulas, reagents, and

catalysts) as well as a written description of the process (on a

laboratory/bench scale if that is all the experience available). Pertinent

scientific publications or patents should be provided (see Glossary). When

significant changes are made in the route of synthesis, or when the scale of

the synthesis changes considerably (as from bench to pilot plant), the IND

should be updated accordingly (by amendment in the case of route change;

by annual report otherwise).

II.A.1.c. Analytical methods

The analytical methods for the NDS should include at least one specific

identity test, one or several impurity tests (preferably some type of

chromatographic examination), and an assay procedure. It is recognized that

any limits set are tentative.

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The elucidation of the structure of the reference standard material, or the

authentic substance, should be documented to the extent possible at this

stage (see section II.F.3.). It is recognized that this may not be feasible for

certain complex substances (e.g., products of natural origin), but adequate

efforts should be made to characterize such substances.

III.A.2. Phase 3

III.A.2.a. Manufacture of the new drug substance 
Drug Substance Page 38

The manufacturing procedure for the NDS should be fairly well established by

the latter part of this stage of development. A description of the process

should be submitted, in sufficient detail to approach the NDA requirements

(see section II.D.). Alternate synthetic pathways/routes employed to prepare

batches used in clinical trials should also be described. The sponsor may

continue to modify, revise, or even totally change the synthesis; such changes

should be reported accordingly (as amendments, or in the periodic report as

warranted).

III.A.2.b. Analytical methods

The sponsor should appropriately update the controls and revise the

specifications for the NDS when extensive (Phase 3) studies are to be

initiated. Before or early in Phase 3, it is expected that all major

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impurities will have been isolated and identified. Levels of impurities, either

individual or total, should be controlled. Information regarding

stereochemistry and its relation to pharmacological and toxicological activities

may also be requested if not already provided (as requested for Phase 1 and

Phase 2 studies). It is also expected that studies of any solid-state form(s) of

the NDS (and their relevance to bioavailability of the drug product) will have

been conducted or initiated during the Phases 1 and 2 studies, and

appropriate specifications developed (if not already provided).

As Phase 3 studies progress, the cumulative manufacturing and controls

information should be updated at suitable intervals. Sponsors should

consider preparation of the samples (including impurity samples) and

information required for the NDA validation package, and perhaps also

consider a pre-NDA manufacturing and controls submission.
Drug Substance Page 39

III.B. Known Chemical Entity (see Glossary)

III.B.1. Sponsor-Investigator Research Study (documentation on file)

The sponsor of a research study can comply with the manufacturing and controls

information requirements by requesting the manufacturer of the

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drug substance or drug product to authorize the agency to refer to a DMF, IND,

or NDA.

When a sponsor-investigator either prepares the dosage form(s) himself from a

commercially obtained drug substance (known chemical entity) or modifies the

drug product, refer to the "Guideline for Submitting Documentation for the

Manufacture of and Controls for Drug Products" for the information required.

A sponsor-investigator is advised to contact the agency when a drug substance

itself is to be altered before making dosage forms (e.g., as in the case of

conversion of a salt to the free base or acid, or to a different salt).
Drug Substance Page 40

III.B.2. Sponsor-Investigator Research Study or Commercial Sponsor (no

documentation of file)

The sponsor of a research study with a drug substance for which the agency

does not have documentation on file can comply with the regulations by

submitting the following: 

II.B.2.a. Best available descriptive name and chemical structure of the NDS;

II.B.2.b. Statement of the source of the NDS, including name and address of

the manufacturer;

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II.B.2.c. A description of the preparation of the NDS, including (when

possible) diagrammatic flow charts of the chemical reactions used in the

synthetic process; 

II.B.2.d. A description of the methods which will be used to determine that the

identity, strength, quality, and purity of the NDS is initially adequate and will

be maintained for the duration of the clinical trial. The sponsor may rely on

the manufacturer's results (i.e., the Certificate of Analysis, and stability

studies) to satisfy this requirement, provided that the sponsor performs a

specific identity test for acceptance.

II.B.2.e. The information requested above should be accompanied by

appropriate scientific literature references.

If an NDA for this type of study is submitted, the review of the NDA could be

delayed if the description of the method of manufacture of the known chemical

entity is not on file (IND, DMF, etc.).
Drug Substance Page 41

IV. CURRENT GOOD MANUFACTURING PRACTICE REQUIREMENTS (CGMP's) 

Bulk pharmaceutical chemicals (BPC's) are the active and inactive components used

by the pharmaceutical industry in the formulation of finished drug products. This

includes any substance that is relabeled or repackaged for drug use.

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Section 201(g) of the Federal Food, Drug, and Cosmetic Act (the act) defines BPC's as

drugs; therefore they must meet all requirements set forth in the act as well as all

pertinent regulations. Since there are no specific regulations for the production of

BPC's, the Commissioner has stated in the preamble to the CGMP regulations for

finished drug products that these regulations will be used as guidance for the

manufacture of BPC's.

For more specific GMP Requirements, including homogeneity and sampling, refer to

the document "Guide to Inspection of Bulk Pharmaceutical Chemical Manufacturing."

Some aspects of manufacturing practice have been considered in Section II.E. 

(Process Controls) of this Guideline; information about these areas should be provided

in NDA submissions.

GLOSSARY

1. Drug Substance An active ingredient, intended for incorporation into a finished

dosage for, that meets the statutory definition of a drug (i.e., that is intended to

furnish pharmacological activity or other direct effect in the diagnosis, cure,

mitigation, treatment, or prevention of disease or to affect the structure or any

function of the human body).
Drug Substance Page 42

2. Drug Product A finished dosage form (e.g., tablet, capsule, or solution) that

contains a drug substance, generally but not necessarily in association with one or

more other ingredients.

3. Pivotal Intermediate An intermediate that is permitted to be prepared by several

different synthetic routes (or fermentation procedures). Pivotal intermediates are

not common in syntheses because the definition requires that there be two or more

distinct and independent methods for their synthesis. Ordinary late-stage

intermediates do not meet the definition, regardless of their importance to the

success of the synthesis (i.e., "Pivotal" does not necessarily mean "vital").

4. Key Intermediate An intermediate in which an essential molecular

characteristic(s), usually involving the proper stereochemical configuration required

for structure/activity (pharmacological and/or physiological activity of the drug

substance), is first introduced into the structure (e.g., introduction of a chiral center,

as exemplified by the Corey aldehyde in prostaglandin syntheses, or the production

of one geometric isomer in preference to another).

5. In Situ Intermediate An intermediate that is not isolated. It is normally but not

necessarily in solution.

6. Final Intermediate By definition this is the last compound synthesized before the

reaction that produces the new drug substance. The final step, forming the new

drug substance, must involve covalent bond formation. However, formation of

simple esters (e.g., methyl, ethyl, etc.) does not qualify as the final synthetic step,

so that the precursor to the unesterified acid is the final intermediate. Complex

esters (where both the alcohol and the acid result from several-step syntheses) are

acceptable. Ionic bond formation (i.e., making the salt of a compound) does not

qualify; thus, when the drug substance is a salt, the precursors to the organic acids
Drug Substance Page 43

or bases should be considered as the final intermediate rather than the acid or base

themselves. There may be more than one final intermediate depending on the

nature of the synthesis (e.g., parallel or shotgun routes, where two or more major

fragments leading to the final molecule are combined).

7. Reference Standard A particular lot or batch of drug substance specifically

prepared, either by independent synthesis or by additional purification of production

material, and shown, by an extensive set of analytical tests, to be authentic material

of the highest purity reasonably attainable. It is usually used for structural

elucidation, and is the benchmark for working standards.

8. Working Standard Drug substance of established quality and purity as shown

by comparison to the Reference Standard material, used as a standard substance

for routine laboratory work, as in analyses of production batches of new drug

substance or drug product(s).

9. Known Chemical Entity A chemical which has been adequately characterized in

the literature with regard to its physical and chemical properties.

10. New Chemical Entity A chemical which has not been adequately characterized

in the literature with regard to its physical and chemical properties. (Not to be

confused with "New Molecular Entity".)

11. Major impurity One that is important either because of the quantity present or

because of its toxicity.

12. New Molecular Entity (NME) A term used by the FDA to describe the subject of

a drug application (IND or NDA) classified as Chemical Type 1 (i.e., an active

moiety not yet marketed in the U.S.A.).
Drug Substance Page 44

13. Chemical Literature This refers to complete published journal articles, patents,

and texts, as indexed by Chemical Abstracts. The FDA Medical Library does not

receive all journals. Copies of articles and patents should be provided to expedite

review, with English translations as required. Recent issues of major American

chemistry journals (e.g., Journal of Medicinal Chemistry) need not be provided.