Q&A ON VALIDATION OF ANALYTICAL PROCEDURES – ICH Q2 GUIDELINE PART -4
Question 1:
How can specificity be demonstrated in chromatographic procedures?
Answer 1:
Specificity in chromatographic procedures can be demonstrated by using representative chromatograms where individual components are appropriately labeled. Critical separations should be investigated, and specificity can be shown by resolving components that elute closest to each other.
Question 2:
What approach should be taken when a non-specific assay is used for drug substance release?
Answer 2:
When a non-specific assay is used for drug substance release, other supporting analytical procedures should be employed to demonstrate overall specificity. For example, a combination of the assay with a suitable test for impurities can be used.
Question 3:
How can the discrimination of the analyte in the presence of impurities and excipients be practically demonstrated in an assay?
Answer 3:
The discrimination of the analyte in the presence of impurities and excipients can be practically demonstrated by spiking pure substances (drug substance or drug product) with appropriate levels of impurities and/or excipients. The assay result should be compared with the result obtained on unspiked samples to show that it is unaffected by the presence of these materials.
Question 4:
What should be done if impurity or degradation product standards are not available during specificity testing?
Answer 4:
If impurity or degradation product standards are not available, specificity may be demonstrated by comparing the test results of samples containing impurities or degradation products to a second well-characterized procedure, such as a pharmacopoeial method or another validated analytical procedure (independent procedure).
Question 5:
How can peak purity tests be useful in demonstrating specificity in chromatographic procedures?
Answer 5:
Peak purity tests can be useful in demonstrating specificity in chromatographic procedures by showing that the analyte chromatographic peak is not attributable to more than one component. Techniques such as diode array or mass spectrometry can be employed for this purpose.
Question 6:
How is linearity evaluated in an analytical procedure?
Answer 6:
Linearity in an analytical procedure is evaluated by assessing the relationship between signals and analyte concentration or content across the specified range. This evaluation involves visual inspection of a plot of signals versus analyte concentration. Additionally, statistical methods, such as regression analysis using the method of least squares, may be employed to assess linearity.
Question 7:
What aspects should be considered during the evaluation of linearity?
Answer 7:
During the evaluation of linearity, aspects such as the correlation coefficient, y-intercept, slope of the regression line, and residual sum of squares should be considered. A plot of the data should be included, and an analysis of the deviation of actual data points from the regression line may also be helpful for evaluating linearity.
Question 8:
What recommendations are provided regarding the number of concentrations to establish linearity?
Answer 8:
A minimum of 5 concentrations is recommended for establishing linearity. However, other approaches should be justified based on the specific analytical procedure and requirements.
Question 9:
How should linearity be demonstrated in analytical procedures like immunoassays?
Answer 9:
In analytical procedures like immunoassays where linearity may not be demonstrated after any transformation, the analytical response should be described by an appropriate function of the concentration (amount) of an analyte in a sample.
Question 10:
Why is it important to assess linearity in an analytical procedure?
Answer 10:
Assessing linearity in an analytical procedure is important as it ensures that the relationship between signals and analyte concentration is linear across the specified range. This verification is crucial for obtaining accurate and reliable quantitative results from the analytical method.
