Method validation Flashcards
Analytical procedure validation data should be submitted in the corresponding sections of what?
The application (ICH M4Q The Common Technical Document For The Registration Of Pharmaceuticals For Human Use) and should be submitted to demonstrate the suitability of the procedure for the intended purpose.
An analytical method validation study is designed to provide what?
Sufficient evidence that the analytical procedure meets its objectives. These objectives are described with a suitable set of performance characteristics and related performance criteria, which can vary depending on the intended purpose of the analytical procedure and the specific technology selected.
What should be included in a method validation protocol?
The protocol should contain information about the intended purpose of the analytical procedure, the performance characteristics to be validated and the associated criteria. In cases where prior knowledge is used (e.g., from development or from previous studies), appropriate justification should be provided. The results of the validation study should be summarised in a validation report.
Do analytical procedures require revalidation?
Changes may be required during the lifecycle of a validated analytical procedure. In such cases, partial or full revalidation may be required. Science and risk-based principles can be used to justify whether or not a given performance characteristic needs revalidation. The extent of revalidation depends on the performance characteristics impacted by the change.
A validated quantitative analytical procedure that can detect changes in relevant quality attributes of a product during storage is considered to be stability-indicating. How do you demonstrate specificity/selectivity of a stability-indicating test?
These can include: samples spiked with target analytes and known interferences; samples that have been exposed to various physical and chemical stress conditions; and actual product samples that are either aged or have been stored under stressed conditions.
How is specificity or selectivity of an analytical procedure demonstrated?
The specificity or selectivity of an analytical procedure can be demonstrated through absence of interference or comparison of results to an orthogonal procedure. In some cases, specificity/selectivity may be inherently given by the underlying scientific principles of the analytical procedure. Some experiments can be combined with accuracy studies.
Selectivity could be demonstrated when the analytical procedure is not specific. However, the test for an analyte to be identified or quantitated in the presence of potential interference should minimise that interference and demonstrate that the analytical procedure is fit for the intended purpose.
Where one analytical procedure does not provide sufficient discrimination, a combination of two or more procedures is recommended to achieve the necessary specificity/selectivity.
What is the range of an analytical procedure?
The range of an analytical procedure is the interval between the lowest and the highest results in which the analytical procedure has a suitable level of response, accuracy and precision. The range can be validated through the direct assessment of reportable results (to generate a reportable range) using an appropriate calibration model (i.e., linear, non-linear, multivariate). 8 ICH Q2(R2) Guideline In some cases, the reportable range can be determined using one or more appropriate working ranges, depending on the sample preparation (e.g., dilutions) and the analytical procedure selected.
Typically, a working range corresponds to the lowest and the highest sample concentrations or purity levels presented to the analytical instrument for which the analytical procedure provides reliable results. Mathematical calculations are typically required to generate reportable results. Reportable range and working range could be identical.
What is linearity
A linear relationship between analyte concentration and response should be evaluated across the range of the analytical procedure to confirm the suitability of the procedure for the intended purpose. The response can be demonstrated directly on the product or suitable reference materials, separate weighings of analyte, or predefined mixtures of the components (e.g., by dilution of a solution of known content), using the proposed procedure.
Linearity can be evaluated with a plot of signals as a function of analyte concentration or content, and should demonstrate the analytical procedure capability across a given range to obtain values that are proportional to the true (known or theoretical) sample values. Test results should be evaluated by an appropriate statistical method (e.g., by calculation of a regression line by the method of least squares).
Data derived from the regression line may help to provide mathematical estimates of the linearity. A plot of the data, the correlation coefficient or coefficient of determination, yintercept and slope of the regression line should be provided. An analysis of the deviation of the actual data points from the regression line is helpful for evaluating linearity (e.g., for a linear response, the impact of any non-random pattern in the residuals plot from the regression analysis should be assessed).
To assess linearity during validation, a minimum of five concentrations appropriately distributed across the range is recommended.
Explain accuracy and precision
Accuracy and precision can be evaluated independently, each with a predefined acceptance criterion. Alternatively, accuracy and precision can be evaluated in combination.
Accuracy should be established across the reportable range of an analytical procedure and is typically demonstrated through comparison of the measured results with expected values. Accuracy should be demonstrated under regular test conditions of the analytical procedure (e.g., in the presence of sample matrix and using described sample preparation steps). 11 ICH Q2(R2) Guideline
Accuracy is typically verified through one of the studies described below. In certain cases, accuracy can be inferred once precision, response within the range and specificity have been established.
Spiking Study - The analytical procedure is applied to a matrix of all components except the analyte where a known amount of the analyte of interest has been added. In cases where all the expected components are impossible to reproduce, the analyte can be added to or enriched in the test sample. The results from measurements on unspiked and spiked/enriched samples are evaluated.
Accuracy should be assessed using an appropriate number of determinations and concentration levels covering the reportable range (e.g., 3 concentrations/3 replicates each of the full analytical procedure).
Accuracy should be reported as the mean percent recovery of a known added amount of analyte in the sample or as the difference between the mean and the accepted true value, together with an appropriate 100(1-α) % confidence interval (or justified alternative statistical interval). The observed interval should be compatible with the corresponding accuracy acceptance criteria, unless otherwise justified.
Validation of tests for assay and for quantitative determination of impurity (purity) includes an investigation of precision.
Precision should be investigated using authentic homogeneous samples or, if unavailable, artificially prepared samples (e.g., spiked matrix mixtures or samples enriched with relevant amounts of the analyte in question).
The extent to which intermediate precision should be established depends on the circumstances under which the procedure is intended to be used. The applicant should establish the effects of random events on the precision of the analytical procedure. Typical variations to be studied include different days, environmental conditions, analysts and equipment, as relevant. Ideally, the variations tested should be based on and justified by using analytical procedure understanding from development and risk assessment (ICH Q14). Studying these effects individually is not necessary. The use of design of experiments studies is encouraged.
How should repeatability be assessed?
Repeatability should be assessed using:
a) a minimum of 9 determinations covering the reportable range for the procedure (e.g., 3 concentrations/3 replicates each) or
b) a minimum of 6 determinations at 100% of the test concentration.
Tell me about Reproducibility
Reproducibility is assessed by means of an inter-laboratory trial. Investigation of reproducibility is usually not required for regulatory submission but should be considered in cases of standardisation of an analytical procedure, for instance, for inclusion of procedures in pharmacopoeias and in cases where analytical procedures are conducted at multiple sites.
The standard deviation, relative standard deviation (coefficient of variation), and an appropriate 100(1-α) % confidence interval (or justified alternative statistical interval) should be reported. The observed interval should be compatible with the corresponding precision acceptance criteria, unless otherwise justified.
What is robustness
The evaluation of the analytical procedure’s suitability within the intended operational environment should be considered during the development phase and depends on the type of procedure under study. Robustness testing should show the reliability of an analytical procedure in response to deliberate variations in analytical procedure parameters, as well as the stability of the sample preparations and reagents for the duration of the procedure, if appropriate. The robustness evaluation can be submitted as part of development data for an analytical procedure on a case-by-case basis or should be made available upon request.
