1 Analytical Method Validation for Assay, Related substances & Dissolution. N A Y A N K S H A T R I 1 8 / 0 1 /
2 Definitions The objective of validation of an analytical procedure is to demonstrate that it is suitable for its intended purpose. (ICH Q2(R1) Guideline) Method validation is the process of demonstrating or confirming that a method is suitable for its intended purpose. Method validation is a distinct phase from method development/ optimization and should be performed subsequent to method development. (FDA Guidance for method validation)
3 Definitions Validation is the confirmation by examination and the provision of objective evidence that the particular requirements for a specific intended use are fulfilled. (ISO/IEC17025) Validation of an analytical procedure is the process by which it is established, by laboratory studies, that the performance characteristics of the procedure meet the requirement for the intended analytical application. (United states pharmacopoeia <1225>)
4 Definitions Methods validation means establishing, through documented evidence, a high degree of assurance that an analytical method will consistently yield results that accurately reflect the quality characteristics of the product tested. (21CFR Part (b) (25))
5 What are the Benefits of Analytical Method Validation? Regulatory Compliance Assurance that Test data from Methods are Reliable Establishment that Test Data are Precise, Reproducible, Accurate, Specific.
6 Method Life Cycle Validation Development Optimization
7 Verification vs. Validation Compendial vs. Non-compendial Methods Compendial methods-verification The process of testing a compendial ANDA drug substance or drug product by compendial procedures in an FDA laboratory for purposes of ensuring compliance with compendial specifications and evaluating the appropriateness of a particular formulation for analysis by the compendial methods. Non-compendial methods-validation The analytical process of actual use testing of the applicant s proposed regulatory method(s) in an FDA laboratory.
8 Data Elements Required for Complete Validation Analytical Performance Characteristics Category I Category II Category III Quantitative Limit test Category IV Specificity Yes Yes Yes Yes Yes Accuracy Yes Yes * Yes No Precision Yes Yes No Yes No Limit of Detection No No* Yes * No Limit of Quantification No Yes No * No Linearity Yes Yes No Yes No Range Yes Yes * Yes No Robustness Yes Yes No Yes No Stability of analyte in solution Yes Yes Yes Yes Yes* * May be required, depending on the nature of the specific test.
9 Data Elements Required for Complete Validation Category I : Includes methods for quantitation for major components of bulk drug substances, drug products and other active ingredients in finished products (Assay of drug substances, Preservatives ). Category II : Includes methods for quantitative determination of impurities in drug substances or degradation products in drug products. (Quantitative impurity assays and Limit tests) Category III: Includes methods determining performance characteristics of drug products (e.g. Dissolution and drug release). Category IV: Identification tests
10 Pre-validation consideration GMP/GLP Consideration Validation SOP Validation Protocols Validation Specifications Validation Samples Validation Standards Reference Standards Instrument Qualification and Calibration Training
11 Specificity Spectrophotometric methods: a. Identification of the active ingredient peak by UV spectra. b. Checking interference due to placebo. High performance liquid chromatographic methods: a. Identification of the active ingredient peak and impurity / degradant peaks by retention time. b. Identification of the peaks due to placebo and diluent. c. Demonstrate peak purity for the active ingredient peak using diode array detector. Check the peak purity of the active ingredient. Prepare test sample as per the test method. Scan and ensure that the peaks due to active ingredient are spectrally homogenous. If necessary used suitably spiked samples.
12 Specificity d. Stability indicating method /Forced degradation study/stress study: - The aim of the forced degradation study is to assure that the proposed method is capable to detect and well separate all the known and unknown impurities from the main peak & from each other. - To establish stability indicating nature of the method, Perform stress study on API and formulation under relevant stress conditions described below. Acid Hydrolysis Alkali Hydrolysis Peroxide Oxidation Humidity stress Thermal stress Photo stress (Overall illumination of not less than 1.2 million lux hours and an integrated near ultraviolet energy of not less than 200 watt hours/square meter or direct exposure to sunlight for suitable period) - Carry out the test by trial and error method with an objective to obtain 10% 30% degradation at least in one stress condition. In addition, to ensure that the peaks are single components, use diode array detector to obtain peak purity information for the analyte peaks.
13 Specificity Spectrophotometric methods : - UV maxima observed should be within ±2 nm of UV maxima reported. - There should not be more than 2.0% interference from placebo at the working wavelength of analysis. High Performance Liquid Chromatographic methods: - No peak should be detected at the retention time of active ingredient / impurity/ degradant peaks from the placebo and diluent. - Impurities should be well resolved from the active ingredient peak. - Active ingredient peak in test preparation should be spectrally homogeneous. - Any degradant produced in the forced degradation study should be well resolved from the active ingredient peak and known impurity peaks. - Active ingredient peak in each degraded sample should be spectrally homogenous.
14 Specificity Diluent: Placebo Preparation:
15 Specificity As Such Test preparation: Spiked Test preparation :
16 Specificity Acid Hydrolysis: Base Hydrolysis:
17 Specificity Oxidative Hydrolysis: Peak Purity Graph:
18 Sensitivity Limit of detection (LOD) & Limit of quantification (LOQ): LOD: This is the lowest amount of an analyte in a sample that can be detected, but not necessarily quantified under stated conditions. LOQ: This is the lowest concentration of analyte in the sample that can be determined with defined precision and accuracy under the stated experimental conditions. (A) Linear regression method. 3.3 Limit of detection concentration = S 10 Limit of quantification concentration = S = Residual standard deviation of regression line S = Slope of calibration curve
19 Sensitivity (B) Signal to noise ratio (2H/h): LOD = 3.3 x noise factor LOQ= 10 x noise factor LOD - The peak should be detected. - Signal to noise ratio should be equal to or greater than 3:1 for liquid chromatographic methods. LOQ - Relative standard deviation for area of six replicate injections should not be more than 10.0% for liquid chromatographic methods and 15.0 % in case of Gas chromatographic analysis. - Signal to noise ratio should be equal to or greater than 10:1 for liquid chromatographic methods.
20 Sensitivity LOD Precision: Injection No Peak Area Mean 362
21 Sensitivity LOQ Precision : Injection No Peak Area Mean 876 SD RSD 2.2%
22 Comparison Selectivity: A selective method gives correct results for all interesting analytes whereas a specific test method gives correct results for the interesting analyte whereas other analytes might interfere each other. Specificity: Outlines the analytical extent to which an analytical substance or substance group can be determined without interference from sample related components.
23 Linearity and Range Minimum 5 different concentrations (by volume/weight) of standard in the range specified as follows: Assay of a drug substance / Formulation 80% -120% of the test concentration Determination of an impurity LOQ to 120% of the specification For dissolution testing +/- 20% over For dissolution profile extended linearity can be performed and lower range can be selected based on dissolution profile data. Range would be 0% to 120% of the test concentration for the dissolution profiling, delayed and sustain release products. Plot a linearity curve of concentration verses absorbance/area. Calculate the correlation coefficient, Slope of regression, Y-intercept, Square of correlation coefficient, Response factor and Y-intercept bias.
24 Linearity and Range Assay: The correlation coefficient should not be less than The square of correlation coefficient should not be less than Relative standard deviation of response factor should not be more than 3.0%, it should not be more than 5.0% in case of analysis done on RI detector or fluorescence detector. Y- intercept bias should be within ±2.0% of 100% linearity level response. Dissolution: The correlation coefficient should not be less than The square of correlation coefficient should not be less than Relative standard deviation of response factor should not be more than 5.0%. it should not be more than 10.0% in case of analysis done on RI detector or fluorescence detector Y- Intercept bias should be within ±5.0% of 100% linearity level response. Related substances : The correlation coefficient should not be less than The square of correlation coefficient should not be less than Relative standard deviation of response factor from 50% to 120% linearity level should not be more than 10.0%. Y- Intercept bias should be within ±15.0% of 100% linearity level response. Range will be defined based on accuracy, linearity and precision parameters.
25 Average area Linearity and Range Linearity of Detector Response: Concentration (µg/ml)
26 Precision For test of assay /dissolution, use samples as such. Prepare six test samples of the same batch for assay and perform dissolution on six units for precision test. Calculate the results as per the test method. For test of related substances / impurities, use samples as such or spiked (Prepare three as such test samples for the impurity subtraction) with available impurities (If found below LOQ). Analyze all the six test preparation and calculate the results as per the test method. Calculate the Mean, Standard deviation and Relative standard deviation of the test results in each case. Intermediate Precision: Repeat the precision test using same sample but under different conditions i.e. different day, different analyst, different instrument, different column (Same dimension and particle size with different make/different serial no.) whichever is feasible.
27 Precision Chromatographic methods: Relative standard deviation for area of replicate injections, Theoretical plates, tailing factor, resolution to be achieved as per System suitability in the test method. Spectrophotometric methods: Relative standard deviation for absorbance of replicate observations should not be more than 2.0%. Assay: The relative standard deviation for six results should not be more than 2.0%. For Preservatives/Antioxidants: The relative standard deviation for six results should not be more than 5.0%. Dissolution: The relative standard deviation for six results should not be more than 10.0 %. Related substances: Impurity level (%w/w) RSD >0.10% to 0.50% NMT 15.0% >0.50% to 1.00% NMT 10.0% More than 1.00% NMT 5.0%
28 Intermediate precision (Reproducibility) Assay: The relative standard deviation for six results should not be more than 2.0%. The difference in average results obtained between two analysis should be not more than 2.0%. For Preservatives/Antioxidants: The relative standard deviation for six results should not be more than 5.0%. The difference in average results obtained between two analysis should be not more than 10.0%. Dissolution: The relative standard deviation for six results should not be more than 10.0 %. The difference in average results obtained between two analyses should not be more than 10% at time points with less than 85% dissolved and should not be more than 5% for time points above 85%. Related substances: Impurity level (%w/w) Difference from precision RSD >0.10% to 0.50% NMT 0.05 NMT 15.0% >0.50% to 1.00% NMT 0.10 NMT 10.0% More than 1.00% NMT 15% NMT 5.0%
29 Accuracy The accuracy of an analytical procedure expresses the closeness of test results obtained by that procedure to the true value. Assay: Prepare recovery samples in triplicate at 80%, 100% and 120% range of the nominal working concentration of the test sample. Dissolution: Prepare recovery samples in triplicate at $ 50%, 100% and 120% range of the nominal working concentration of the test sample. Note: In case of multiple strengths, consider accuracy concentration as follows: - $ 50% for Lowest range of the lowest strength, 100% of the middle strength and 120% for upper range of the highest strength. In case of delayed and sustained release formulation, perform accuracy from LOQ level. $ For dissolution profile extended accuracy can be performed and lower range can be selected based on dissolution profile data. Related substances: Prepare recovery samples at LOQ level of active ingredients, 50%, 100% and 120% range of nominal concentration. Wherever applicable prove accuracy at LOQ, 50%, 100% and 120% range for impurity also. This can be done by spiking the active ingredient, impurities, degradants in the placebo/sample in suitable concentrations.
30 Accuracy Assay: The recovery of active ingredient should be between 98.0% and 102.0%. Relative standard deviation for recovery at each level should not be more than 2.0%. Related substances: Impurity level (% w/w) Recovery (%) >0.100 to to >0.500 to to More than to Relative standard deviation for recovery at each level should not be more than 10.0%. For Dissolution test: For Immediate release tablets: The recovery of active ingredient should be between 95.0% and 105.0%. Relative standard deviation for recovery at each level should not be more than 5.0%. For Modified release tablets: Recovery level (%w/w) Recovery (%) RSD (%) LOQ to less than 50.0% 75.0% to 115.0% NMT 15.0% 50.0% to 120.0% 85.0% to 110.0% NMT 5.0%
31 Robustness Spectrophotometric methods: Variation in wavelength (±2 nm) Liquid chromatographic methods: Variation in ph (±0.2 units) Variation in wavelength of detection (± 2 nm) Variation in solvent ratio of the mobile phase composition. (±5% relative) Variation in column oven temperature (±5 C) Variation in the flow rate (±10%) Dissolution methods: Variation in speed of dissolution apparatus(±4%) Variation in ph of dissolution medium(±0.5 units) Variation in surfactant concentration(±10%w/v)
32 Random and systematic deviations precise and accurate not precise but accurate precise but inaccurate e not precise and inaccurate
33 Stability of analyte in solution This parameter is performed to determine the maximum time that the standard / sample should be used in analysis after its preparation. Prepare single set of standard and duplicate test sample as mentioned in the test method. In case of related substances/residual solvents, spike the test sample with available known impurities (If found below LOQ). Store the solution in tight flasks for specified time intervals at C. If the solution is not stable at above condition perform the study at 2-8 C.
34 Stability of analyte in solution Assay/Dissolution tests : The area/absorbance/potency of standard preparation and area/absorbance/results of test preparation should not differ by more than 2.0% from the initial area / absorbance/potency/results. Related substances: Impurity level (% w/w) Difference from Initial >0.10 to 0.50 NMT 0.05 >0.50 to 1.00 NMT 1.00 More than 1.00 NMT 15.0% The area/potency of standard preparation should not differ by more than 5.0% from the initial area / potency.
35 Filter Study This parameter is performed to select the best suitable filter for analysis. Perform this test using different types of filters (Minimum two types of filters). For Assay/Dissolution: Perform the study on 100% of test concentration as per the method of analysis and calculate the difference of results between filtered sample and centrifuged sample. For Related substances: Use test preparation prepared as per method of analysis spiked with the available impurities (If found below LOQ) and Determine the percentage of impurities in test preparation for all filters as per test method and calculate the difference of results against centrifuged sample results.
36 Filter Study Assay: The percentage assay of any of the filtered sample should not differ by more than 2.0% from that of the centrifuged sample. Dissolution: The percentage dissolution of any of the filtered sample should not differ by more than 2.0% from that of the centrifuged sample. Related substances: Impurity level (% w/w) Difference from Centrifuge >0.10 to 0.50 NMT 0.05 >0.50 to 1.00 NMT 1.00 More than 1.00 NMT 15.0%
37 References Validation of Compendial Methods (USP <1225>) Verification Compendial Procedures (USP <1226>) Validation of analytical procedures: Text and Methodology Q2(R1) (ICH guideline) Chromatographic Separation Technique (Ph.eur ) Analytical procedure and method validation (CDER guideline) Guideline for the validation and verification of quantitative and qualitative test method (NATA (National association of testing authorities, Australia) Harmonized guidelines for single laboratory validation of methods of analysis (IUPAC technical report)
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