Quality control bioanalytical applications

Applications of HPLC Of the bioanalytical separation technologies described in this book, arguably HPLC has the widest range of applications, being adopted for the purpose of clinical, environmental, forensic, industrial, pharmaceutical and research analyses. While there are literally thousands of different applications, a few indicators of how HPLC has been used are as follows (i) Clinical quantification of drugs in body fluids (ii) Environmental identification of chemicals in drinking water (iii) Forensic analysis of textile dyes (iv) Industrial stability of compounds in food products (v) Pharmaceutical quality control and shelf-life of a synthetic drug product (vi) Research separation and isolation of components from natural samples from animals and plants. 

Repeatability is obtained when the analysis is performed in one laboratory by one analyst using the same equipment at the same day. Repeatability should be tested by the analysis of a minimum of five determinations at three different concentrations (low, medium and high) in the range of expected concentrations, according to FDA [16], However according to the ICH [79] repeatability could be measured by the analysis of three determinations at three different concentrations or through six determinations at 100 % of the test concentration. The latter one is for analysis when the concentration is supposed to be constant for all samples, e.g., pharmaceutical products. The acceptance criteria for precision depends much on the type of analysis. For compound analysis in pharmaceutical quality control, precision should be better than 2 % [82], For bioanalytical applications the precision values at each concentration level should be better than 15 % except for the lower limit of quantification (LLOQ) where is should not exceed 20 % [16], The intermediate precision shows the variations affected in day-to-day analysis, by different analysts, different instruments etc. Reproducibility, as above, represents the precision obtained between different laboratories. 

The focus of this chapter is on quality assurance and quality control issues facing clinical laboratories, with emphasis on chromatographic analysis. Chromatography is a versatile analytical technique with diverse applications including gas chromatography (GC), liquid chromatography (LC), GC or LC coupled with mass spectrometry (MS) and other qualitative and quantitative bioanalytical methods. 

This chapter reviews the use of HPLC in pharmaceutical analysis from drug discovery to quality control. The focus is on HPLC analysis of drug substances (DS) and products (DP) such as assay for potency, purity evaluation, and dissolution testing. A case study of the various HPLC methods used during early clinical development illustrates the versatility of this technique. Detailed descriptions of HPLC applications in pharmaceutical development and LC/MS analysis in drug discovery and bioanalytical studies can be found elsewhere.1-6 The regulatory aspects in pharmaceutical testing are covered in Chapter 9. 

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