Analytical method validation specificity

Analytical methods and specifications must be established and validated so as to define and control the quality and purity of the raw materials, intermediates and the finished product. For many standard chemical raw materials, the development of specifications will not be necessary as they are already published in US and European pharmacopoeia (for example, standards for water, organic solvents and various excipients). The ultimate objective of these activities is to be able to manufacture the drugs required for clinical trials in accordance with good manufacturing practice (GMP). 

Verification implies that the laboratory investigates trueness and precision in particular. Elements which should be included in a full validation of an analytical method are specificity, calibration curve, precision between laboratories and/or precision within laboratories, trueness, measuring range, LOD, LOQ, robustness and sensitivity. The numbers of analyses required by the NMKL standard and the criteria for the adoption of quantitative methods are summarized in Table 10. 

Traceability and MU both form parts of the purpose of an analytical method. Validation plays an important role here, in the sense that it confirms the fitness-for-purpose of a particular analytical method [4]. The ISO definition of validation is confirmation by examination and provision of objective evidence that the particular requirements of a specified intended use are fulfilled [7]. Validation is the tool used to demonstrate that a specific analytical method actually measures what it is intended to measure and thus is suitable for its intended purpose [2,11]. In Section 8.2.3, the classical method validation approach is described based on the evaluation of a number of method performance parameters. Summarized, the cri-teria-based validation process consists of precision and bias studies, a check for... 

Typical parameters that are generally considered most important for validation of analytical methods are specificity, selectivity, precision, accuracy, extraction recovery, calibration curve, linearity, working range, detection limit, quantification limit, sensitivity, and robustness. 

The following principles should be used to establish a valid analytical method A specific detailed description and protocol should be written (standard operating procedure (SOP)). Each step in the method should be investigated to determine the extent to which environmental, matrix, material, or procedural variables, from time of collection of material until the time of analysis and including the time of analysis, may affect the estimation of analy te in the matrix. A method should be validated for its intended use with an acceptable protocol. Wherever possible, tire same matrix should be used for validation purposes. The concentration range over which the analyte will be determined must be defined in the method, on the basis of actual standard samples over the range (standard curve). It is necessary to use a sufficient number of standards to adequately define the relationship between concentration and response. Determination of accuracy and precision should he made by analysis of replicate sets of analyte samples of known concentration from equivalent matrix. 

For analytical method validation during full development (after final synthesis has been set for drug substance and after final market formulation has been set for drug product) corresponding to the definitive control procedure for new drug application (NDA), a specific validation protocol has to be written. Before start of the experimental work, the protocols must be written... 

As required by regulatory authorities [1-3, 6] and International Conference on Harmonisation (ICH) guidelines [7], analytical method validation is especially important in establishing the assay methods and procedures of quantitative or semi-quantitative measurement of target substances or compounds. Among the specification items for drug products, assay, content uniformity, and dissolution are typical of those which require almost full analytical validation. The purity test, related... 

One should verify that the method of recordkeeping in the development laboratory follows what is stipulated in the FDA s Laboratory Inspection Guide, from June 1992. The system should also be evaluated for the transfer of validated analytical methods. On-site validation of the method is required for analytical methods validated at another laboratory. A written procedure should be available covering both the transfer of methods and onsite validation and revalidation. When contract laboratories are being used, verification that the laboratory is using the correct analytical methods and specifications should be performed. 

Test methods used in the laboratory are generally derived from pharmacopeias such as the US Pharmacopoeia, British Pharmacopoeia or European Pharmacopoeia. For test methods that are not from recognized pharmacopoeias, validation of the analytical methods is required. The validation includes testing for accuracy, specificity, ruggedness, robustness, precision, detection limit, quantitation limit and range. A discussion of analytical methods validation is presented in Section 9.6.5. 

Process validation, formally articulated in 1987 and similar in theory to analytical method validation, is defined as ... establishing documented evidence which provides a high degree of assurance that a specific process will consistently produce a product meeting its pre-determined specifications and quality attributes. ... 

Method validation is covered in the current Good Manufacturing Practices (cGMPs) under section 211.165(e) which indicates that The accuracy, sensitivity, specificity, and reproducibility of tests methods. .. shall be established and documented . Such validation and documentation may be accomplished in accordance with 211.194(a) (2) which includes the need to indicate the location of data that establish that the methods used in the testing of the sample meet proper standards of accuracy and reliability as applied to the product tested . Methods included in recognized standard references such as the current USP/NF are understood to be validated. The suitability of all testing methods used shall be verified under actual conditions of use (211.194). For new products for which methods are developed, analytical method validation as described in this chapter will be necessary for methods already included in the USP, method verification will suffice. 

The process of method validation (i.e., evaluation of the assay) affects the quality of the quantitative data directly [9 A Guide to Analytical Method Validation, Waters Corporation]. Through method validation, it is assured that the method developed is acceptable. Issues involved in the validation of a mass spectrometry method for quantitative analysis are similar to those in any other analytical technique. The validation involves undertaking a series of studies to demonstrate the limit of detection G OD) limit of quantitation (LOQ) linear range specificity within-day precision and accuracy and day-to-day precision and accuracy, specificity, and robustness of the method. All of these parameters must be determined with those commonly accepted good laboratory practices criteria that are applicable in the vafidation of analytical methods. 

The specification development process is a data-driven activity that requires a validated analytical method. The levels of data needed include assay precision, replicate process results (process precision), and real-time stability profiles. A statistical analysis of these data is critical in setting a realistic specification. Most often, aggregation and fragmentation degradation mechanisms are common to protein and peptide therapeutics. Therefore, the SE-HPLC method provides a critical quality parameter that would need to be controlled by a specification limit. 

Some internationally harmonized guidelines regarding specifications and tests, impurities and validation of analytical methods have particular relevance to the development of chiral drugs and are discussed below. In addition, the impact of work on the common technical document is considered. 

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