Compendial testing by ketan mishra

COMPENDIAL TESTING
PREPARED BY
KETAN MISHRA
MPHARM QARA SEM -2
ROLL NO -5
GUIDED BY
MISS KRUPA THULLA
ASSIST. PROF.
M PHARM QA DEPARTMENT

CONTENTS
• INTRODUCTION
• HISTORY OF THE UNITED STATES PHARMACOPEIA
• U.S. PHARMACOPEIA–NATIONAL FORMULARY
• THE PHARMACOPEIAL FORUM
• COMPENDIAL TESTING FOR FORMULATED PRODUCTS AND ACTIVE
INGREDIENTS
• IDENTIFICATION OF ACTIVE PHARMACEUTICAL INGREDIENTS
• IDENTIFICATION TESTS SPECIFIC TO ACTIVE INGREDIENTS
• REFERENCE

3
compendial testing Comprises all of the analytical testing
required to prove the identity, efficacy, and safety of drug
products before they are packaged or distributed.
At the Suffern site the manufacturing facility for Novartis
Pharmaceuticals Corporation (NPC) in the United
States, the quality assurance laboratories are responsible
for testing raw materials, active ingredients, and
formulated products.
Introduction

a variety of analytical techniques are used ranging
from very simple physical testing to complex
chromatographic separations.
the degree of testing that a product requires
depends on the characteristics of the
compound, the number of the components in the
product, and the dosage form

5
A result of the efforts of Dr. Lyman Spalding of New York City in 1817.
The United States would be divided into four districts and delegates would
represent each of the medical associations and schools situated within it.
Each district would hold a convention at which time a pharmacopeia would be
drafted, and representatives were appointed to attend a General Convention
that would be held in Washington, DC.
At the General Convention, the four district pharmacopeias would be compiled
into a single National Pharmacopeia.
Through the authority of the Medical Society of the State of New
York, Dr. Spalding’s plan went into effect.
HISTORY OF THE UNITED STATES PHARMACOPEIA

Cont….
• The first U.S. Pharmacopeial Convention assembled in
Washington, DC, on January 1, 1820, and on December
15, 1820, the first U.S. Pharmacopeia was published.
• At this first convention, it was decided that a revised USP edition
would be published every 10 years.
• In 1900 the decision was made to issue supplements to the USP in
the interim between new editions, and in 1940 the period for new
editions was changed from every 10 years to every 5 years.
• The primary objective of the USP is to compile a select list of
pharmaceuticals every 5 years, including medicinal substances and
preparations that are still covered under patent rights.
6

U.S. Pharmacopeia–National Formulary
• The pharmacopeia contains monographs, procedures for general tests
and assays, and a section on reagents and solutions for drug
substances, drug products, nutritional supplements, and excipients.
• The products can be labeled as “USP,” which indicates compliance with
the specifications designated in the pharmacopeia.
• The USP works closely in conjunction with the FDA, the pharmaceutical
industry, and health professionals in establishing their standards, which
are enforceable by the FDA and the governments of more than 35
countries.
• Failure to comply with USP–NF standards and test methods can result
in products that are adulterated, leading to a variety of negative
outcomes including FDA recalls and warning letters.
• USP also provides reference standards.
• USP also holds various events like “Children and Medicines” and
“Communicating Risk to Patients.”
7

The Pharmacopeial Forum
• It provides the arena for proposed and forthcoming revisions to the
USP–NF.
• It is published six times per year by the USP, allowing public review to
official pharmaceutical standards before they become effective.
• It encourages a free exchange of ideas and information among the
scientists involved in the development of analytical test methods.
• It is divided into two main sections: Pharmacopeial Previews and In-
process Revision.

Pharmacopeial Previews
• Contains new methods that are being presented to the industry for the
first time.
• USP Monographs, NF Monographs, and General Chapters for chemical
tests and assays are included within this section.
• New monographs may be proposed for new drug substances or new
dosage forms.
• The General Chapters section contains test methods specific to
particular drug substances or dosage forms.
• Following a method’s debut in the Pharmacopeial Previews
section, comments may be submitted to the Subcommittee regarding
the proposed monograph or method.
• These comments would then appear in the In-process Revision section
of the Pharmacopeial Forum.

In-process Revision
• Contains the actual corrections and changes suggested by the industry
readers to improve the proposed monograph or method.
• Therefore, it contains not only the original wording from the
Pharmacopeial Previews, but also the proposed changes, allowing the
reader to see the history of the review process.
• Following receipt of comments on monographs or methods, they are
reviewed by the Subcommittee who will in turn propose them for official
adoption into the USP.
• Once the Division of Standards Development (DSD) Executive
Committee gives approval, the Board of Trustees approves publication
and that monograph or method will be slated for the next Supplement to
the USP or USP–NF edition.

• Typical quality control (QC) laboratories test raw materials, active
ingredients, and finished products with different kinds of testing being
required for each.
• The testing for most raw materials follows compendial methods
whereas testing for most finished products does not.
• For new drug products containing new drug substances, there are no
compendial methods.
• Once marketing approval is granted for a new product by the
appropriate regulatory agency, the testing methods used in the
development of the product will be incorporated into the USP as the
official compendial methods.
• Other situations exist in which a new product contains a previously
approved drug substance that may have already-existing compendial
methods.
• The existing compendial methods may not be appropriate for the new
product and new methods may need to be developed.

COMPENDIAL TESTING FOR FORMULATED PRODUCTS AND ACTIVE
INGREDIENTS
• When a new product is being considered for marketing in more than
one country, besides the FDA, the regulatory agency for the United
States, applications will also be submitted to the regulatory agencies of
other countries. Japan, Britain, and Europe each have their own
pharmacopeias, testing methods, and specifications.
• When new drug applications (NDAs) are submitted, sometimes, as we
will see, the regulatory agencies will not agree on the degree of
testing, and additional testing could be required for products to be
distributed in certain countries.
• In recent years, there has been an effort to harmonize compendial
requirements with significant progress being made in certain areas.
• The products discussed were chosen because they have unique and
interesting testing procedures and intriguing molecular structures and
are marketed in a variety of dosage forms.
• Particular attention will be given to USP requirements.

COMPENDIAL TESTING FOR FORMULATED PRODUCTS AND ACTIVE
INGREDIENTS
• Four analytical tests that are considered universal by the FDA for
formulated products: description, identification (ID), assay, and
impurities.
• Descriptions of active ingredients and raw materials just describe the
physical appearance of the substance.
• These tests represent the minimum testing requirements for a batch of
drug product to be released by the quality assurance laboratory.
• Additional tests may be required depending on the characteristics of the
particular drug substance and the dosage form.
• For drug substances that are marketed in more then one dosage
form, different methods or variations of existing methods might be
needed for each.
• In most testing laboratories, in-house quality standards (QS) exist for
each product and strength.
• The QS may also contain sample HPLC chromatograms, UV/visible
spectra, and IR spectra to aid the analyst in carrying out each test.

Descriptions of Active Ingredients and Solid Oral Dosage Forms
• A description test is a qualitative physical description of the drug
product including the dosage form and any visual characteristics:
size, shape, color, and any other identifying markings.
• The description test is critical and if it is incorrect, that particular batch
of product is immediately considered defective.
• Description testing is not included in the USP because the physical
description of products is unique to the manufacturer.
• Generic products containing the same drug substance have their own
identifying markings different from those of the branded product.

Identification of Active Pharmaceutical Ingredients
• To confirm the identity or presence of the active ingredient by employing
a variety of analytical techniques and methods.
• For drug formulations, the drug substance may need to be extracted
from the dosage form. New techniques such as near-IR spectroscopy
may eliminate the need to isolate the active ingredient.
• Once the pure compound is obtained, a spectroscopic technique such
as UV, IR, or melting point will be used to compare the sample identity
to that of a standard that has been similarly prepared.
• The characteristics of the compound will help define which type of
spectroscopy will be most useful.
• The goals of identification testing is that it must be specific enough to
distinguish between compounds with similar structures including
starting materials and degradation products.
• In some cases, nonspecific methods are sometimes used in conjunction
to obtain a positive ID.

Identification of Active Pharmaceutical Ingredients
• HPLC is a commonly used analytical technique with the retention time
being indicative of the compound.
• However, HPLC retention time is not usually regarded as specific for
identification testing, but can be used in conjunction with other tests
such as thin-layer chromatography (TLC), IR spectroscopy, UV/visible
spectroscopy, or other physical tests such as melting point. When
retention time is used, the standard and sample must elute at similar
times.
• Many drug substances are used in the form of a salt. The identification
of these materials may also include a test for the specific counterion
used.
• Common counterions used in pharmaceuticals are
sodium, chloride, and pamoate ions.

Identification of Active Pharmaceutical Ingredients & solid
dosage form
• Metoprolol tartrate is a synthetic drug substance used for the treatment
of hypertension. The drug substance is a 2:1 salt that contains a
racemic mixture of optical isomers of metaprolol and naturally occurring
dextrotartaric acid.
• Both the active ingredient and the tablet form have different testing
requirements.
• Metaprolol tartrate tablet testing uses UV and IR spectroscopy for
metaprolol ID, TLC for the tartrate ion ID, and HPLC retention time for
identification.
• The IR spectroscopy test is carried out by dissolving approximately
136mg of finely ground tablets and in 25mL of water with 4mL of
ammonium hydroxide (1:3). After extraction with chloroform, the organic
layer is dried over anhydrous sodium sulfate, evaporated, and placed in
a freezer to congeal the crystals. Once formed, the crystals are
triturated with potassium bromide and used in pellet form to obtain an
IR spectrum that is then compared to that of a standard similarly
prepared.

The TLC test for the tartrate ion
• Sample and standard solutions of equal concentration are spotted on a
chromatography plate & allowed to develop. If the substances in the
sample and standard solutions are the same, they will have identical Rf
values.
• Most organic compounds are not colored and do not fluoresce within
the visible light range, i.e., are not visible to the naked eye and require
some form of visualization.
• In most cases, UV light enables the analyst to see the spots and
calculate the Rf value.
• In contrast, the injectable form of metoprolol tartrate requires only IR
identification with a procedure almost identical to that for the tablet form.
• The only difference is that a specific volume of the injectable
solution, which is already dissolved in water, is used in the extraction.
This is a good example of a situation where only a slight modification of
the analytical procedure was needed for two very different dosage
forms.

• Carbamazepine is an analgesic and anticonvulsant distributed as
tablets, chewable tablets, and an oral suspension.
• The active ingredient, tablet, and oral suspension dosage forms have
distinctly different identification procedures.
• The carbamazepine active ingredient has an identification test unique
for testing raw materials, X-ray diffraction.
• Each crystalline form of a compound yields its own unique X-ray
diffraction pattern, which is considered a form of identification. X-ray
diffraction patterns can be obtained from a single crystal or from a
sample of powder and then can be used for quantitative and qualitative
analysis of the substance.
• For the tablet form of carbamazepine, an IR spectrum is obtained with a
procedure slightly different from that for metaprolol. To carry out the
test, 360mg of powdered tablets is boiled in 15mL of
acetone, filtered, and evaporated to around 5mL using a stream of
nitrogen. Cooling in an ice bath gives rise to crystals, which after
filtration and drying are used in a Nujol mull to obtain an IR spectrum.

• Terbutaline sulfate, which is a synthetic β2-adrenoceptor that is used as
a bronchodilator for the treatment of asthma.
• The compound is available in inhalation aerosol, injectable, and tablet
dosage forms. The inhalation aerosol is the most unique of the three
dosage forms.
• The aerosol consists of a suspension of fine terbutaline sulfate in a
pressurized aerosol container equipped with a metered dose valve and
oral inhalation actuators.
• To extract the sample from the aerosol, 10 filled containers are chilled to
−75 C in an acetone–dry ice mixture for 15–20 min. After the tops are
removed and the containers are allowed to sit, the contents are poured
into a beaker. A portion of this mixture is extracted into chloroform and
filtered through a medium-porosity sintered glass funnel. After the
residue is washed with chloroform and allowing to air-dry, the crystals
are then used to form a KBr pellet and obtain an IR spectrum.

• For terbutaline tablets, TLC is used to identify the active ingredient.
• The tablets are dissolved in dilute ethanol and centrifuged. The
insoluble excipients fall to the bottom and the ethanol solution
containing the active ingredient is used to spot the TLC plate. The plate
is developed using a mixture of cyclohexane, isopropyl alcohol, and
formic acid as eluants, and air-dried.
• In contrast to the tartrate TLC analysis for metaprolol, which used UV
light to visualize the spots, the terbutaline TLC analysis uses a specific
reagent sprayed onto the plate to assist in visualizing the spots.
• After the plate is sprayed with a spray reagent, the spots appear
colored with the color change indicative of the class of compound and
the reagent used. In the case of terbutaline, a phenol derivative, 4-
aminoantipyrine–potassium ferricyanide is used. Separate solutions of
4-aminoantipyrine and potassium ferricyanide are prepared and the
plate is sprayed with each.
• Exposing the sprayed plate to 25% ammonium hydroxide results in red-
orange to pink spots indicative of phenols. Numerous spray reagents
are known and are specific for different classes of compounds.

Identification Tests Specific to Active Ingredients
• Identification tests for pure drug substances can be different from those
for formulated products. Many times, tests for the specific counterion
drug substance will be performed on the active ingredient. These tests
are very general and oftentimes can follow official compendial methods.
• Imiprimine hydrochloride is the original tricyclic antidepressant and is a
member of a class of compounds known as dibenzazepines.
• Imiprimine is a hydrochloride salt available in tablet and injectable
dosage forms.
• The counterion for imiprimine hydrochloride, chloride, is identified as
part of the active ingredient.
• To carry out the test, the sample powder is dissolved in alcohol, and 2 N
nitric acid is added along with 3 drops of a silver nitrate test solution.
• A white precipitate of silver chloride is formed, which dissolves upon
addition of ammonium hydroxide, confirming the presence of the
chloride ion.
• As chloride identification is used for the testing of the drug substance, it
is not required for the formulated product.

• Imiprimine is also available as a pamoate salt. The QS ID test uses TLC
to identify the pamoate ion.
• A standard solution of pamoic acid is prepared by dissolving it in a
sodium hydroxide solution. The pamoate ion is extracted from the
dosage form by dissolving the tablet powder in a sodium hydroxide
solution and extracting the active ingredient with chloroform. The
pamoate ion remains in the water layer and the chloroform layer is
discarded.
• Both the sample and standard solution are spotted on a TLC plate and
eluted with a mixture of acetic acid, ethyl acetate, water, and
hydrochloric acid.
• The plate is developed, dried, and sprayed with a potassium
dichromate-detecting reagent to visualize the spots.
• The simple ion-exchange reaction like that used to identify simple
counterions (e.g., chloride or sulfate) cannot be used for the pamoate
ion

Imiprimine hydrochloride Imiprimine pamoate
• The test for ID of the counterion associated with terbutaline sulfate is
similar to that for imiprimine HCl. A water solution of terbutaline sulfate
is prepared and acidified with hydrochloric acid. Upon addition of a few
drops of barium chloride solution, a white precipitate forms, which
indicates barium sulfate.

• The drug substance reserpine is an optically active molecule containing
six asymmetric carbons. One of the properties unique to optically active
compounds is their ability to rotate plane-polarized light.
• The degree of rotation depends on the concentration of the sample and
the length of the sample path.
• The specific rotation, denoted [α]D, takes these parameters into
consideration and is a measure of a compound’s ability to rotate plane-
polarized light.
• All pure optically active compounds have their own specific
rotation, which can be used to identify them. The angular rotation of
reserpine is determined using a solution of known concentration in
chloroform.
• The angular rotation is then measured using a polarimeter at room
temperature and compared with a standard.
• Both the physical and chemical properties of the molecule and dosage
form challenge the analyst by requiring expertise in wet and
instrumental chemistry to correctly identify the material under study.

REFERENCE
• Handbook of modern pharmaceutical
analysis, Edited by Satinder Ahuja and
Stephen Scypinski, page no- 325-333.

Compendial testing by ketan mishra

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