Immunoassay technology is an analytical method with high sensitivity and specificity; it provides a technique to assay materials which cannot be measured by other methods, or are difficult to detect. It plays a very important role in biological sample pre-treatment, therapeutic drug monitoring and drug determination, and is one of the important means for in vivo drug analyses. This paper reviews immunoassays commonly used in bioanalysis, including immunoextraction and immunodepletion for pretreatment of biological samples, conventional immunoassay methods and new immunoassay technologies for determination of target drugs.
To compare the pharmacokinetics properties of enalapril-felodipine sustained-release tablet with enalapril and felodipine in the two reference formulations in Chinese healthy volunteers, the study was designed to a randomized, open label, crossover and two treatment pharmacokinetic study using enalapril-felodipine sustatined-release tablet as the test formulation. A total of 12 individuals were randomly assigned to 2 gorups （6 individuals in each group）. The wash-out period was 14 d. Compared with the reference formulations, felodipine in the sustained-release tablet showed significantly sustained-release characteristics, while the pharmacokinetics processes of enalapril and its active metabolite enalaprilat were basically similar in Chinese healthy volunteers.
