Analytical Method Validation in Pharmaceuticals | Step-by-Step Guide to AMV

In pharmaceutical quality control, analytical method validation (AMV) is one of the most critical aspects that helps to ensure that methods used to test raw materials, intermediates and finished products are reliable, accurate and suitable for their analysis. Without analytical method validation, pharmaceutical companies may have risk of regulatory noncompliance, product recalls and most importantly patient safety issues.

In this post, we will understand the concept of analytical method validation (AMV), its importance, regulatory requirements, validation parameters and best practices for pharmaceutical industry.

What is Analytical Method Validation?

Analytical method validation in pharmaceutical industry is a documented process to demonstrate that an analytical method is suitable for analysis of the raw material, intermediate or finished product that is analyzed using this method. It provides evidence that the method is consistently producing reliable results of analysis when applied under defined analytical conditions.

For example, if any pharmaceutical company develops a method for assay determination to quantify the API quantity in tablets. Before analyzing samples, this method must be validated for its accuracy, precision and reproducible results in multiple labs, by different analysts and using different instruments.

Why is Method Validation Important?

Regulatory regulations are very strict in pharmaceutical industry. Regulatory guidelines such as ICH guidelines, FDA requirements and EU-GMP standards require validation of analytical methods because:
1. Ensures Accuracy and Reliability – It ensures that test results truly represent the sample’s quality ensuring accuracy and reliability.
2. Regulatory Compliance – Regulatory agencies require analytical method validation before product approvals.
3. Patient Safety – Accurate testing of material ensures that medicines are safe, effective and free from harmful impurities and contaminations.
4. Consistency in Manufacturing – It helps in maintaining product quality in different batches ensuring consistency in manufacturing.
5. Facilitates Technology Transfer – Validated methods can be transferred between different sites and labs without reliability issues.

Regulatory Guidelines for Analytical Method Validation

Different regulatory agencies provide detailed guidelines on analytical method validation (AMV). Widely followed guidelines for AMV are:
ICH Q2(R1): Validation of Analytical Procedures – Text and Methodology is a widely accepted document for analytical method validation in pharmaceuticals.
FDA Guidance for Industry: Analytical Procedures and Methods Validation (2015) has detailed knowledge for analytical method validation.
USP (United States Pharmacopeia) General Chapter <1225>: Validation of Compendial Procedures defines the validation requirements for pharmaceutical industry.
EMA Guidelines on Analytical Method Validation: It has basic concepts for analytical method validation.
These guidelines provide the outline of the analytical method validation including parameters, acceptance criteria and documentation requirements for validation process.

Types of Analytical Methods in Pharmaceuticals

Analytical methods those are used for analysis of pharmaceutical products depends on the nature of drug product. Common analytical methods categories include:
1. Identification Tests – These tests are used to confirm the identity of an API or excipient.
2. Assay Methods – Assay tests are useful to quantify the amount of API in any pharmaceutical product.
3. Impurity Tests – Impurity tests help in detecting and quantifying degradation products, residual solvents and other impurities in pharmaceutical products.
4. Physical Tests – These tests determine properties such as dimensions, friability, particle size, pH and dissolution and disintegration time of the product.

Key Analytical Method Validation Parameters

1. Accuracy

Accuracy is the degree of agreement of test results with the true value, or the closeness of the results obtained by the procedure to the true value. It is normally established on samples of the material to be examined that have been prepared to quantitative accuracy. Accuracy should be established across the specified range of the analytical procedure.
Note: it is acceptable to use a “spiked” placebo where a known quantity or concentration of a reference material is used.

2. Precision

Precision is the degree of agreement among individual results. The complete procedure should be applied repeatedly to separate, identical samples drawn from the same homogeneous batch of material. It should be measured by the scatter of individual results from the mean (good grouping) and expressed as the relative standard deviation (RSD).
2.1 Repeatability should be assessed using a minimum of nine determinations covering the specified range for the procedure e.g. three concentrations/ three replicates each, or a minimum of six determinations at 100% of the test concentration.
2.2 Intermediate precision expresses within-laboratory variations (usually on different days, different analysts and different equipment).
If reproducibility is assessed, a measure of intermediate precision is not required.
2.3 Reproducibility expresses precision between laboratories.

3. Robustness

Robustness (or ruggedness) is the ability of the procedure to provide analytical results of acceptable accuracy and precision under a variety of conditions. The results from separate samples are influenced by changes in the operational or environmental conditions. Robustness should be considered during the development phase, and should show the reliability of an analysis when deliberate variations are made in method parameters.
Factors that can have an effect on robustness when performing chromatographic analysis include:
— stability of test and standard samples and solutions;
— reagents (e.g. different suppliers);
— different columns (e.g. different lots and/or suppliers);
— extraction time;
— variations of pH of a mobile phase;
— variations in mobile phase composition;
— temperature; and
— flow rate.

4. Linearity

Linearity indicates the ability to produce results that are directly proportional to the concentration of the analyte in samples. A series of samples should be prepared in which the analyte concentrations span the claimed range of the procedure. If there is a linear relationship, test results should be evaluated by appropriate statistical methods. A minimum of five concentrations should be used.

5. Range

Range is an expression of the lowest and highest levels of analyte that have been demonstrated to be determinable for the product. The specified range is normally derived from linearity studies.

6. Specificity

Specificity (selectivity) is the ability to measure unequivocally the desired analyte in the presence of components such as excipients and impurities that may also be expected to be present. An investigation of specificity should be conducted during the validation of identification tests, the determination of impurities and assay.

7. Limit of Detection (LOD)

Limit of Detection is the smallest quantity of an analyte that can be detected, and not necessarily determined, in a quantitative fashion. Approaches may include instrumental or non-instrumental procedures and could include those based on:
— visual evaluation;
— signal to noise ratio;
— standard deviation of the response and the slope;
— standard deviation of the blank; and
— calibration curve.

8. Limit of Quantitation (LOQ)

Limit of Quantitation is the lowest concentration of an analyte in a sample that may be determined with acceptable accuracy and precision. Approaches may include instrumental or non-instrumental procedures and could include those based on:
— visual evaluation;
— signal to noise ratio;
— standard deviation of the response and the slope;
— standard deviation of the blank; and
— calibration curve.

9. System Suitability Testing (SST)

System suitability testing is an integral part of many analytical procedures. The tests are based on the concept that the equipment, electronics, analytical operations and samples to be analyzed constitute an integral system that can be evaluated as such. System suitability test parameters that need to be established for a particular procedure depend on the type of procedure being evaluated, for instance, a resolution test for HPLC procedure.

Steps in Analytical Method Validation

1. Define the Purpose – Establish the intended use of test like assay, impurity test, etc.
2. Prepare Validation Protocol – Document the scope, acceptance criteria, and procedure in validation protocol.
3. Conduct Validation Experiments – Perform experiments for each method validation parameter.
4. Analyze Data – Compare results against acceptance criteria for each parameter.
5. Prepare Validation Report – Document all results, deviations, and conclusions in validation report.
6. Approval – QA/Regulatory teams review and approve the validation report.

Common Challenges in Method Validation

• Variation in analytical results between different labs.
• Difficulty in detecting trace level impurities.
• Requirement of high cost and time for extensive validation.
• Regulatory expectations change from time to time.
• Improper documentation during method validation studies.

Best Practices for Successful Method Validation

• Always align with globally accepted regulatory guidelines by following ICH and USP guidelines.
• Always use validated and calibrated instruments.
• Properly train analysts to reduce variability and human errors.
• Document everything during method validation process to complete validation protocol and report.
• Perform ongoing verification by monitoring methods as a part of validation lifecycle.

Never consider analytical method validation just to regulatory requirement. It is the foundation of pharmaceutical product quality. Pharmaceutical companies validate their analytical methods to ensure that their products are safe, effective and compliant with regulatory standards. Investing in analytical methodology is not optional for pharmaceutical companies but it is a essential to protect patients and maintain compliance with regulatory agencies.

FAQs on Analytical Method Validation

Q1. What is analytical method validation?

Answer: Analytical method validation is a documented process that demonstrates the suitability of an analytical method. It ensures accuracy, precision, specificity and reproducibility of test results.

Q2. Why is analytical method validation important?

Answer: Validation of analytical methods is important in pharmaceutical industry because it ensures reliability and consistency of results and fulfills regulatory requirements from agencies like FDA, EMA and WHO.

Q3. What types of analytical methods require validation?

Answer: Any method that is used to test pharmaceutical products or materials requires validation whether it is an identification test, essay, impurity test, dissolution or physical parameters.

Q4. What are the key parameters for method validation?

Answer: As per ICH Q2(R1), parameters include:

• Accuracy
• Precision (repeatability & intermediate precision)
• Specificity
• Linearity and range
• Limit of Detection (LOD)
• Limit of Quantitation (LOQ)
• Robustness
• System suitability

Q5. What is the difference between accuracy and precision?

Answer: Accuracy determines the closeness of results to the true value.
Precision shoes the closeness of repeated measurements to each other.

Q6. What is specificity in method validation?

Answer: Specificity of an analytical method is the ability to measure the sample without interference from impurities, excipients and degradation products.

Q7. When should an analytical method be revalidated?

Answer: Revalidation of an analytical method is required when method is transferred from one lab to another lab or manufacturing site, any major change occurs in method or equipment, any change is in product formulation or at any regulatory agency request.

Q8. What is the difference between method validation and method verification?

Answer: Validation is a comprehensive evaluation of analytical method that proves method's suitability while verification confirms that an existing method performs as per requirement of laboratory.

Q9. How long does analytical method validation take?

Answer: Time duration for analytical method validation depends on complexity of the method. It may take few weeks to several months to complete experiments and data analysis.

Q10. Who is responsible for analytical method validation?

Answer: Analytical method validation is usually conducted by quality control laboratory and finally approval is given by quality assurance.

Get ready to use editable Validation Protocols in MS-Word FormatView List

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