Purity Testing: regulatory needs and analytical method requirements

Purity Testing – regulatory needs and analytical

method requirements

RPD 5th Year Anniversary 04.05.2012

Dr. Stefanie Seitz

22

www.hwi-pharma-solutions.com3

Purity Testing – regulatory needs and analytical method

requirements

› Regulatory needs

› Method development

› Stress studies

› Identification of impurities

› Validation of analytical methods

Content

Presentation: Purity Testing – regulatory needs and analytical method requirements


Classification of impurities


› Organic impurities (process-, drug-, excipient-related)

› Starting materials

› By-products

› Intermediates

› Degradation products

› Residual solvents

› Reaction products with excipients

› Leachables from container closure systems

› Inorganic impurities

› Reagents, ligands and catalysts

› Heavy metals or other residual metals

› Inorganic salts

› Other materials (e.g., filter aids, charcoal)


Regulatory needs – ICH Guidelines

› CPMP/ICH/2737/99: NOTE FOR GUIDANCE ON IMPURITIES TESTING: IMPURITIES IN NEW

DRUG SUBSTANCES

› CPMP/ICH/2738/99: NOTE FOR GUIDANCE ON IMPURITIES IN NEW DRUG PRODUCTS

› =>Distinct limits:

› Reporting limit (= Ph. Eur. Disregard limit)

› Identification limit

› Qualification limit

› � Action limits!

› Specification of:

› Identified impurities

› Specified unidentified impurities

› Unspecified identified impurities

› Sum of impurities



Regulatory needs – ICH Guidelines

CPMP/ICH/2737/99 & 2738/99


›The CHMP/CVMP QWP has prepared a series of guidelines, which provide recommendation on the information which has to be submitted in an application file for marketing authorisation (MA). It is assumed that these guidelines represent the current knowledge on technical and scientific progress.

›In Europe, the pharmaceutical legislation makes no distinction between the quality requirements for new active substances and the quality requirements for existing generic active substances (Directives 2001/83 and 2001/82 as amended). Therefore in principle (V)ICH guidelines adopted as EU guidelines may also equally apply to new products containing existing/known active substances.


CPMP/ICH/2737/99 - IMPURITIES IN NEW DRUG SUBSTANCES


› This document is intended to provide guidance for registration applications on the content and qualification of impurities in new drug substances produced by chemical syntheses and not previously registered in a region or member state.

› It is not intended to apply to new drug substances used during the clinical research stage of development.

› The following types of drug substances are not covered in this guideline: biological/biotechnological, peptide, oligonucleotide, radiopharmaceutical, fermentation product and semi-synthetic products derived there from, herbal products, and crude products of animal or plant origin.


CPMP/ICH/2738/99 - IMPURITIES IN NEW DRUG PRODUCTS


› This guideline addresses only those impurities in new drug products classified as degradation products of the drug substance or reaction products of the drug substance with an excipient and/or immediate container closure system (collectively referred to as "degradation products" in this guideline).

› Generally, impurities present in the new drug substance need not be monitored or specified in the new drug product unless they are also degradation products (see ICH Q6A guideline on specifications).

› Impurities arising from excipients present in the new drug product or extracted or leached from the container closure system are not covered by this guideline.


Method development for purity testing


› Performance of stress studies

› Selectivity of the used methods

› Integration of impurities

› Identification of impurities


Stress studies in method development for purity testing

› are of fundamental importance

› for the development of "stability-indicating methods“

› for the evaluation of potential degradation products (-pathways)

› to discriminate between different types of impurities

› to determine the stability of drug substance and drug product



Stress testing (CPMP/QWP/122/02, corr.)

› Stress testing is likely to be carried out on a single batch of the active substance.

› It should include the effect of temperatures (in 10°C increments (e.g., 50°C, 60°C, etc.) above that for accelerated testing, humidity (e.g., 75 % RH or greater) where appropriate, oxidation, and photolysis on the active substance.

› The testing should also evaluate the susceptibility of the active substance to hydrolysis across a wide range of pH values when insolution or suspension.

› Photostability testing should be an integral part of stress testing. The standard conditions for photostability testing are described in the Note for Guidance on Photostability Testing of New Active Substances and Medicinal Products (CPMP/ICH/279/95)



Properties of a molecule



Performance of stress testing


Hydrolysis

Oxidation

Isomerisation

Racemisation

Epimerisation

Rearrangement

Acid

Base

Oxidant

pH

Temperature

Humidity



› Acid: 1 % and 5% of sample solution, pH = 1, 60 °C , closed container, test

period: 2-3 days

› Base: 1 % and 5% of sample solution, pH 10, 60°C, closed container, test

period: 2-3 days

› Humidity: 25°C/75% r. h. and 40°C/75% r. h. , storage in open containers,

testing period: one week




› Humidified samples, different temperatures (50 °C - 90°C) in closed

container, testing period: one week

› Temperature: dry, different temperatures (50 °C – 90 °C), closed containers,

testing period: one week

› Oxidation: 1% and 5% sample solution, 0,03 % H2O2, different temperatures

(30°C - 50°C), closed containers, testing period: some days



Method development


0 20 40 60 80Time (min)

120min, 60°C

0 10 20 30 40 50 60 70 80 90 100Time (min)

120min, 30°C

0 10 20 30 40Time (min)

40min, 60°C

0 10 20 30 40Time (min)

40min, 30°C


Determination of integration parameters


13,2

41

14,1

97

AU

-0,010

0,000

0,010

0,020

0,030

0,040

0,050

0,060

0,070

Minutes12,00 13,00 14,00 15,00 16,00

13,2

41

14,1

83

AU

-0,010

0,000

0,010

0,020

0,030

0,040

0,050

0,060

0,070

Minutes12,00 13,00 14,00 15,00 16,00


Determination of integration parameters



Strategies for identification

› Literature search HPLC/MS Data??

› Evaluation of suitable conditions for forced degradation

› In-situ generation of target impurity by forced degradation of the API

› (Selective) Extraction

› Purification, e.g.

› (Flash) Chromatography on silica gel

› Further purification on Sephadex®/C-18

› (Synthesis of the impurity)

› Structure elucidation (NMR, X-Ray,…)



Strategy of structure elucidation

› 1H-NMR with signal assignment

› 13C-NMR with signal assignment

› 2D-NMR-spectra for an unambiguous assignment

› Mass spectra, e.g. EI, ESI, CI, etc..

› interpretation of spectra (molecule ion & fragmentation)

› high resolution mass spectra (?)

› IR spectroscopy with assignment of characteristic absorption bands

› UV/VIS spectroscopy

› Literature search with recorded data!



Strategy of structure elucidation

› 3D structure

› X-ray diffraction (single crystals?)

› Polymorphic forms / Solid state characterisation

› X-ray diffraction (powder / single crystals?)

› Raman spectrometry

› IR

› Absolute configuration / Enantiomeric purity

› X-ray structure analysis

› Polarimetry



Validation of analytical methods


› Q2 (R1): Validation of Analytical Procedures: Text and Methodology

› Note for Guidance on Validation of Analytical Methods: Definitions

and Terminology (CPMP/ICH/381/95)

› Note for Guidance on Validation of Analytical Procedures:

Methodology (CPMP/ICH/281/95)

› „The objective of validation of an analytical procedure is to

demonstrate that it is suitable for its intended purpose.“

› „It is the responsibility of the applicant to choose the validation

procedure and protocol most suitable for their product.“


Validation of analytical methods – ICH guideline



Validation protocol – validation report


› Introduction

› Principle of the method (assay, purity, ...)

› Reference to the analytical method

› Sample and Reference standards

› Composition

› Specification




› Validation parameter

› Specificity

› Linearity / Range

› Accuracy

› Repeatability / intermediate precision

› Detection limit / Quantitation limit

› Robustness




› Summary, table

› Statistic evaluation of the data

› Evaluation of the results with repect to the acceptance criteria

› Deviations

› Chromatograms


Validation - Specificity

› Proof of the identity of the drug substance by comparison with a reference standard

› Retention time and spectrum (UV, MS)

› Co-injection of drug substance and reference standard

› Acceptance criteria

› No interference with Drug substance

› Proof of peak purity

› Chromatograms of

› Solvent

› Reference standard

› Drug substance

› Drug substance + Reference standard

› Matrix

› Drug product



Validation - Specificity

› Chromatograms of

› Identified impurities, individually

› Drug product, spiked with impurity

› Stress testing (acidic, basic, oxidative, reductive, thermal)

› Reference samples of „aged“ batches

› Reference solution at specification limit and reporting level



Validation - Linearity

› „A linear relationship should be evaluated across the range of the analytical procedure.“

› „The correlation coefficient, y-intercept, slope of the regression line and residual sum of squares should be submitted. A plot of the data should be included.“

› Minimum specified ranges to be considered

› purity: reporting level - 120 % of specification

› Purity 100 % method: reporting level – 120 % of the assay specification

› Validation is performed using the drug substance as well as identified impurities





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Area

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Legende

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Konfidenzintervall

y = 82967451,4447x - 11072,1573

Konf(0)=[-75076,6173 ; 52932,3026]

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Are

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Gesamtparabene [mg/mL]




› Evaluation of the residuals


Validation - Range


› „The specified range is normally derived from the linearity studies and

depends on the intended application of the procedure.“

› „It is established by confirming that the analytical procedure provides

an acceptable degree of linearity, accuracy and precision when

applied to samples containing amounts of analyte within or at the

extremes of the specified range of the analytical procedure.“


Validation - Accuracy


› „application of the analytical procedure to synthetic mixtures of the

product components to which known quantities of the substance to

be analysed have been added“

› „in cases where it is impossible to obtain samples of all product

components, it may be acceptable to add known quantities of the

analyte to the product or to compare the results from a second, well

characterised procedure, the accuracy of which is stated and/or

defined (independent procedure)“


Validation - Accuracy


› Proof of accuracy by determination of recovery

› Impurity is spiked to drug product: concentration of the impurity

at n = 3 levels (reporting level, specification, 200 % of the

specification, each n = 3 determinations)

› accuracy for unknown impurities on the drug substance or

identified impurity

› Acceptance criteria

› recovery = 90 - 110 %

› COV < 10 %


Validation - Precision



Validation - Repeatability


› Precision with minimum of n = 6

› Drug product, if impurities are present

› Reference samples of „aged“ batches

› Stressed samples

› Acceptance criteria: COV < 5 - 10 %


Validation – Intermediate precision


› according to the repeatability

› Acceptance criteria:

› precision: COV < 5 - 10 %

› if necessary, compare the mean values: deviation of the mean values with respect to the higher value of <10%


Validation – Limit of quantitation (LOQ)


› Required for quantitative determination of impurities

› LOQ <= reporting level

› Options

› based on the signal-to-noise ratio S / N ≥ 10:1

› based on visual analysis

› based on the calculation of standard deviation / slope

› based on the standard deviation of the blank sample

› based on a calibration curve

› Presentation of the relevant chromatograms


Validation – Limit of determination (LOD)


› Required for limit tests of impurities

› LOD <= ½ reporting level

› Options

› based on the signal-to-noise ratio S / N ≥ 3:1

› based on visual analysis

› based on the calculation of standard deviation / slope

› based on the standard deviation of the blank sample

› based on a calibration curve

› Presentation of the relevant chromatograms


Validation – Robustness


› Sample preparation

› e.g. extraction of a sample

› Extraction of impurities_ validation on drug substance and impurity reference standards

› Behaviour of unknown impurities

› amount of substance

› Amount of extractant

› Extraction conditions, e.g. shaking, stirring, mixing, extraction time, extraction temperature


Validation – Robustness


› HPLC / GC method:

› Colum, e.g. batch, different suppliers

› Pre-columns

› Gradient or temperature program

› Flow rate

› pH-value and composition of solvents

› Detection wavelength

› Stability of Reference standard

› Stability of sample

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42

thank you very much for your attention!


Glossary I› Impurity: Any component of the drug substance/product that is not the chemical

entity defined as the drug substance. Any component of the new drug product that is not the drug substance or an excipient in the drug product

› Reporting Threshold: A limit above which an impurity should be reported. Reporting threshold is the same as reporting level in Q2B

› Identification Threshold: A limit above which a impurity should be identified

› Degradation Product: An impurity resulting from a chemical change in the drug substance/drug product brought about during manufacture and/or storage of the drug substance/drug product by the effect of, for example, light, temperature, pH, water, or by reaction with an excipient and/or the immediate container closure system

› Identified Impurity: A impurity for which a structural characterisation has been achieved

› Unidentified (Specified) Impurity: A impurity for which a structural characterisation has not been achieved and that is defined solely by qualitative analytical properties (e.g., chromatographic retention time).



Glossary II› Unspecified Impurity: A degradation product that is limited by a general acceptance

criterion, but not individually listed with its own specific acceptance criterion, in the specification

› Specified Impurity: A impurity that is individually listed and limited with a specific acceptance criterion in the specification. A specified degradation product can be either identified or unidentified

› Qualification: The process of acquiring and evaluating data that establishes the biological safety of an individual impurity or a given degradation profile at the level(s) specified

› Qualification Threshold: A limit above (>) which a impurity should be qualified.

› Potential Impurity: An impurity that theoretically can arise during manufacture orstorage. It may or may not actually appear in the new drug substance/drug product

› Other detectable Impurity: Specific EP category



Literature – regulatory needs


Note for Guidance on impurities testing: Impurities in new drug productsCPMP/ICH/2738/99

Note for Guidance on impurities testing: Impurities in new drug substancesCPMP/ICH/2737/99

Guideline on control of impurities in pharmacopeial substancesCPMP/QWP/1529/04

Note for Guidance specifications: Test procedures and acceptance criteria for new drug substances and new drug products: Chemical substances

CPMP/ICH/367/96

Guideline on chemistry of the new active substanceCPMP/QWP/130/96 Rev 1

Note for Guidance on summary of requirements foractive substances in the quality part of the dossier

CHMP/QWP/297/97Rev 1 corr


Literature - Validation


Note for Guidance on validation of analytical procedures: Definitions and terminology

CPMP/ICH/381/95

Note for Guidance on validation of analytical procedures: Methodology CPMP/ICH/281/95

Documents

Purity Testing: regulatory needs and analytical method requirements