ANALYTICAL METHOD AND ITS SUITABILITY

Analytical method or procedure: 

The analytical procedure refers to the procedure or steps necessary to perform each analytical test. 

This may include but is not limited to: the method & instrument parameters, the sample/ reference standard & the reagents preparations, use of the apparatus, dilutions required, generation of the calibration curve, use of the formulae for the calculation, etc. 

In-house developed Analytical Method: 

The analytical method that was not listed in any of the pharmacopeias like USP, EP, IP, and JP and developed as per the internal requirements. 

All the in-house developed analytical methods should be validated and transferred to the laboratories where commercial batch analysis shall be performed. 

Compendial or Pharmacopoeial Analytical Method: 
The analytical method that was listed in any of the pharmacopeias like USP, EP, IP, and JP…etc. 

All the compendial or pharmacopoeial methods considered to be validated and only verification to be performed to demonstrate that the procedure is suitable for the intended purpose. 

If a method is listed in pharmacopeias like USP, EP, IP, and JP…etc, but you want to use the same method with modification or completely different methods then you should show method equivalency between your method & the method listed in monographs. 

Analytical method Validation: 
Analytical method validation is the process of demonstrating that the analytical procedure is suitable for its intended purpose. 

The following characteristics shall be considered for the demonstration of method suitability for its intended purpose. 

Method Validation Parameter	Purpose	Procedure
Specificity	Interference Study. To verify whether the interested peak is spectrally pure or not? i.e. peak response is due to a single component only and no co-elutions exist.	Specificity of the method shall be demonstrated by analyzing the sample spiked with all known impurities at specification level and showing that no interference of impurities at the retention time of main peaks.
Precision	To verify the degree of repeatability of the analytical method under normal conditions. Usually expressed as a standard deviation. Minimum of six determinations at 100% of the test or target concentration	Repeatability	Repeatability is the results of the method operating over a short time interval under the same conditions
		Reproducibility	Reproducibility expresses the precision between laboratories (collaborative studies, usually applied to standardization of methodology).
		Intermediate Precision	Intermediate precision is the result from within lab variations due to random events such as different days, analysts, equipment, etc. If reproducibility is performed then intermediate precision not required.
Accuracy	To verify the exactness of the analytical method or closeness of the accepted reference value and actual value found from the experiment.	Collecting data from a minimum of nine determinations over a minimum of three concentration levels covering the specified range (for example, three concentrations, and three replicates each).  The data should be reported as the percent recovery of the known, added amount, or as the difference between the mean and true value with confidence intervals.
Limit of Detection	The lowest amount of analyte in a sample which can be detected but not necessarily quantitated as an exact value.	S/N ratio is determined by comparing  signals from the analyte of known low concentrations samples with blank samples and determining the minimum concentration at which the analyte can be consistently detected.  S/N ratio between 3:1 or 2:1 is considered as acceptable for estimating the detection limit. The detection limit (DL) can be expressed as DL = 3.3 σ/S where σ is the standard deviation of the peak response S is the slope of the calibration curve formed concentration vs response
Limit of Quantitation	The lowest amount of analyte in a sample which can be quantitatively determined with suitable precision and accuracy. And is used particularly for the determination of impurities and/or degradation products	Determination of the S/N ratio is done by comparing measured signals from known low concentrations samples of an analyte with those of blank samples and by establishing the minimum concentration at which the analyte can be consistently quantified.  A typical S/N ratio is 10:1 The quantitation limit (QL) may be expressed as: QL = 10 σ/S where σ is the standard deviation of the peak response S is the slope of the calibration curve formed concentration vs response
Linearity	Ability to get test results within the given range  that are proportional to the concentration (amount) of the analyte in the sample	Guidelines specify a minimum of five concentration levels, along with certain minimum specified ranges.  For the assay, the minimum specified range is from 80-120% of the target concentration.  For an impurity test, the minimum range is from the reporting level of each impurity, to 120% of the specification. (For toxic or more potent impurities, the range should be commensurate with the controlled level.)  For content uniformity testing, the minimum range is from 70-130% of the test or target concentration, and for dissolution testing, +/- 20% over the specified range of the test.
Range	lower and upper concentration (amounts) interval of analyte in the sample (including lower & upper concentrations) for which it has been proven that the analytical the procedure has a suitable level of precision, accuracy, and linearity.
Robustness	The measure of analytical method capacity to remain unaffected by small, but deliberate variations in method parameters and provides an indication of its reliability during normal usage.	The robustness of an analytical  method is assessed by deliberately varying method parameters such as temperature, ionic strength, pH & % organic etc., and evaluating the effect (if any) on the results of the analytical method.
Ruggedness	The degree of reproducibility of the results obtained under a variety of conditions, expressed as %RSD.	These conditions include different laboratories, analysts, instruments, reagents, days, etc.
Solution Stability	To establish the stability of the sample and standard solutions	Sample & Standard solutions to be analyzed at periodic times.
System Suitability	To verify the system suitability parameters	All system suitability parameter to be verified as per respective testing procedure.

Analytical method Transfer: 

Analytical method transfer is a documented process that qualifies a laboratory to use an analytical test procedure that originated in another laboratory thus ensuring that the laboratory has the procedural knowledge and ability to perform the test. 

If the receiving laboratory participated in the collaborative study (Reproducibility as part of the precision study) during the validation of the analytical method, then the same shall be reported as Co-Validation and the laboratory can be considered as qualified for use of analytical test method. 

If the receiving laboratory has not participated in the Validation study then method transfer activity shall be performed as follows to qualify a lab to use the test method. 

In-direct method Transfer (Inter Lab): 

Analysis of the same samples (Single batch), six times at both the transferring unit & receiving unit by using the same analytical method. However, the transferring unit can consider data from the method validation study. 

Direct method Transfer (Inter Lab): 

Analysis of the same samples (Single batch), six times by both the analyst of the transferring unit & receiving unit by using the same analytical method at the receiving laboratory. 

Analytical method Verification: 

Users should have the appropriate experience, knowledge, and training to understand and be able to perform the compendial procedures as written. 

Verification should be conducted for all compendial procedures in a way such that the verification results will provide assurance that the procedure will perform consistently as intended. 

Verification requirements should be based on an assessment of the complexity of both the procedure and the material to which the procedure is applied. 

Although complete revalidation of a compendial method is not required to verify the suitability of the method under actual conditions of use, some of the analytical performance characteristics listed at the analytical method validation section may be used for the verification process. 

Only those characteristics that are considered to be appropriate for the verification of the particular method need to be evaluated. The degree and extent of the verification process may depend on the level of training and experience of the user, on the type of procedure and its associated equipment or instrumentation, on the specific procedural steps, and on which article(s) are being tested. 

Routinely performed basic compendial test procedures do not require verification unless there is an indication that the procedure is not appropriate for the article under test. Examples include, but are not limited to, residue on ignition, loss on drying, several wet analysis procedures such as simple instrumental methods such as pH measurements & acid value. However, for the application of already established routine procedures to compendial articles tested for the first time, it is recommended that consideration be given to any new or different sample handling or solution preparation requirements. 

Analytical method Equivalency: 

Equivalency demonstrates the sameness of two analytical methods. 

Method equivalency comes in to picture whenever you want to use different methods against to monograph method and/or already filed methods during product registrations. 

The goal of method equivalency is to demonstrate acceptable method performance by comparison of a specific set of results (e.g., an assay). I.e. the method proposed is equally capable as a monograph / already filed method to analyze the interesting samples.