Topic 2 Pharmaceutical analysis data treatment. Validation of analytical procedures
- Page ID
- 67828
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)to get an idea about the rules of pharmaceutical analysis data treatment and reporting, the scope and process of validation of analytical procedures, consolidate knowledge in problem solving and laboratory work.
Analytical signals treatment and transformation into the analytical data concerning the nature and amount of a substance, its chemical structure or spatial location of the sample are important components of the pharmaceutical analysis. The result of analysis not statistically treated is of little value.
According to the pharmacopoeial and GMP requirements analytical procedures used for drugs quality control should be validated.
The purpose of validation process is to confirmation experimentally that the analytical procedure provides relevant and reliable information about the object of analysis, and is suitable for its intended purpose.
All quantitative tests (assays) should be validated, including impurities limit tests. Identification tests are validated if it is necessary to confirm their specificity.
Validation of analytical procedures (especially those that will be used as the official process) is regulated by series of standards issued by National and International organizations:
- Russian State Pharmacopoeia XII OFS 42-0113-09 «Validation of Analytical Procedures»
- USP <1225> Validation of Compendial Procedures
- ICH (Q2A, Q2B) Validation of Analytical Procedures: Text and Methodology.
Validation of analytical methods should be evaluated on the following characteristics – the validation parameters:
- Accuracy;
- Precision;
- Specificity;
- Detection Limit;
- Quantitation Limit;
- Linearity;
- Range;
- Robustness.
Guidelines for choosing the parameters of validation are shown in Table 2.1.
[Table 2.1]
Revalidation of an analytical procedure is performed in case of:
- changes in drug manufacturing process (the object of analysis);
- changes in the drug's composition;
- changes in the previously approved analytical procedure.
Trueness with regard to a set of measurements involves a combination of two components: Accuracy and Precision.
Accuracy is characterized by the closeness of the test result obtained by the procedure to the true value (Fig. 2.1). The value of the bias (systematic error) is an indicator of the accuracy. An analytical procedure to be validated is recognized accurate, if the values accepted as conventionally true are within the confidence intervals of the relevant average tests results obtained by this procedure.
[Fig. 2.1]
There are different approaches for assessing the accuracy of quantitative tests (assays):
- analysis by validated procedure using Reference Standards (RS) or model mixtures to which known quantities (concentration) of the drug substance to be analyzed;
- comparison of the results of the proposed analytical procedure with those of a second well-characterized procedure, the accuracy of which is stated and/or defined;
- consideration the results linearity of proposed analytical procedure: if the absolute term of equation y = b × x + a is not statistically different from zero, then the use of this procedures give results free of bias.
Precision is characterized by the scattering of the results obtained by the procedure to the average value (Fig. 1). This characteristic depends only on random factors and not connected with the true value to be measured. The Measure of this scattering is the standard deviation of individual measurement obtained for a sufficiently large amount of sampling.
Precision is assessed for all quantitative tests (assay) using the results of at least three determinations for 3 levels of values to be measured (lower, middle and upper), which are within the range. In many cases, the precision can be evaluated based on the experimental data by least square method.
Precision study is performed using homogeneous samples and can be assessed in three ways:
- as repeatability;
- as within-laboratory (intermediate) precision;
- as between-laboratory reproducibility (precision).
The results of analytical procedures estimation for each of the options are usually characterized by the corresponding value of the Standard Deviation of individual determination with the number of degrees of freedom.
Usually the repeatability of the results obtained by the original procedure is estimated in the development process. In case of inclusion of the developed analytical procedure in normative document, within-laboratory (intermediate) precision should be estimated additionally. Between-laboratory reproducibility (precision) of analytical procedure should be estimated with its proposed inclusion in the General Pharmacopoeial Article, Pharmacopoeial Article or RS normative document.
Repeatability is assessed by individual measurements results obtained in the same laboratory conditions (the same operators, the same equipment or reagents within a short period of time) (Fig. 1). Repeatability is estimated by the relative standard deviation (RSD), which should not exceed 2%.