ANALYTICAL METHOD VALIDATION

ANALYTICAL METHOD VALIDATION

                                                                                   Deepak garg

                                                                            M Pharmacy Pharmaceutics

                                                             Mob. 9915903556

ANALYTICAL METHOD VALIDATION

PRINCIPLE

This annex presents some information on the characteristics that should be considered during validation of analytical methods.Approaches other than those specified in this annex may be followed and may be acceptable.Manufacturer should choose a validation protocol and procedures must be suitable for testing of their product.

The manufacturer should demonstrate (through validation) that the analytical procedure is suitable for its intended purpose.

Analytical methods,whether stability indicating or not,should be validated.

The validated analytical method should be transferred from research and development to the quality control unit when appropriate.

GENERAL

There should be specifications for materials and products .The tests to be performed should be described in standard test methods.

Specifications and standard test methods in Pharmacopoeia(“pharmacopoeia  methods”), or suitably developed specifications or test methods(“non pharmacopoeia methods),as approved by National Drug Regulatory Authority may be used.

Well characterised reference materials, with documented purity, should be used in the validation study.

The most common analytical procedures include identification tests,assay testing of  drug substances and pharmaceutical products ,quantitative tests for impurity content and limit tests for impurities.Other analytical  procedures include for instance dissolution testing and particle size determination.

Analytical results should be reliable ,accurate and reproducible.The characteristics that should be considered during  validation of  analytical methods,are discussed in paragraph 6.

Verification or revalidation should be performed when relevant .This may be necessary when e.g. there are changes in the synthesis of the drug substance;changes in the composition of the finished product; changes in the analytical procedure; when analytical methods are transferred from one laboratory to another laboratory;or when major pieces of equipment  or instruments change.

The verification or degree of revalidation depend on the nature of the change.

PHARMACOPOEIA METHODS

When pharmacopoeia methods are used, evidence should be available to prove that the methods are suitable for routine use in lab (verification).

Pharmacopoeia methods used for determination of content or impurities in Pharmaceutical products should also demonstrate that the methods are specific with respect to the substance(no placebo interference).

NON-PHARMACOPOEIA METHODS

Non pharmacopoeia methods should be appropriately validated.

METHOD VALIDATION

Validation should be performed in accordance with the validation protocol.The protocolshould include procedures and acceptance criteria for all characteristics.The results should be documented in the validation report.

Justification should be provided when non pharmacopoeia methods are used if pharmacopoeia methods are available.Justification should include data such as comparative data with pharmacopoeia or other methods.

Standard test methods should be detailed and should provide suff. Information to allow properly trained analysts to perform the analysis in a reliable manner.It should include atleast the chromatographic conditions.

CHARACTERISTICS OF ANALYTICAL PROCEDURES

Characteristics that should be considered during validation of analytical methods incude:

·         Specificity
·         Linearity
·         Range
·         Accuracy
·         Precision
·         Detection limit
·         Quantitation limit
·         Robustness

·         System suitability testing(e.g. for chromatographic determination)

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 materials to be examined that have been prepared to quantitative accuracy .Accuracy should be established across the specified range of the analytical procedure.

PRECISION is the degree of agreement among the 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 mean(good grouping) and expressed as standard deviation(RSD)

REPEATIBILITY should be assessed using a minimum of 9 determinations covering the specified range for the procedure e.g. 3 concentrations/3 replicates each,or a minimum of 6 determinations at 100% of the test concentration.

INTERMEDIATE PRECISION expresses within laboratory variations ( usually diff. Days, diff. Analysts and diff. Equipment ).If reproducibility is performed intermediate precision is not required.

ROBUSTNESS (ruggedness) is the ability of procedure to provide analytical results of acceptable accuracy and precision  under a variety of  conditions.Results  from separate are influenced by changes in operational or environmental conditions.Robustness should be considered during  the development phase  and should  show the reliability of an analysis wrt deliberate variations in method parameters .

Factors that can have an effect include in chromatographic analysis:

·         Stability of test and standard samples and solutions
·         Reagents (e.g. diff suppliers)
·         Different columns (different lots and suppliers)
·         Extraction time
·         Variation of ph of mobile phase composition
·         Temperature
·         Flow rate

LINEARITY indicates the ability to produce results that are directly proportional to concentration of the analytes in samples. A series of samples should be prepared having analyte  concentration.  If there is linear relationship  test results should be evaluated by appropriate statistical methods. A minimum of 5 concentration should be used.

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.

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

DETECTION LIMIT (LIMIT OF DETECTION) is lowest level of an analyte  that can be detected and not necessarily determined, in a quantitative  fashion . Approaches may include procedures that are instrumental or non instrumental and could include those based on :

·         Visual evaluations

·         Signal to noise

·         Standard deviation of the response to the slope

·         Standard deviation of the blank

·         Calibration curve

Characteristics (including tests) that should be considered for different types of analytical procedures are summarised in Table1.

TABLE 1. Characteristics to consider during analytical validation

Type of analytical procedure characteristics	identification	Testing for impurities	Testing for impurities	Assay Dissolution (measurement only) content/ potency
		Quantitative tests	Limit tests
accuracy	-	+	+	+
Precision Repeatability Interm.precision*		+ +	- -	+ +
Specificity	- -	+	+	+
Detection limit	+	-**	+	-
Quantitation limit	-	+	-	-
Linearity	-	+	-	+
Range	-	+	-	+

  

-          Characteristic is normally not evaluated

+    Characteristic should normally be evaluated