The development of bioanalytical method is of paramount importance during the pre-clinical and clinical stage of drug development. Analytical method development where the appropriate bioanalytical method with its various parameters is developed and the assay is defined and application of the bioanalytical to actual analysis of sample from bioavailability, bioequivalence and pharmacokinetic studies. Bioanalytical methods are used for the quantitative analysis of drugs and their metabolites in the biological matrices like saliva, plasma, blood, serum, urine. In method development sample preparation and sample analysis are two important part. For sample analysis generally chromatographic technique are used like (HPLC, LC-MS/MS, GC, UPLC). After method development validation of that bioanalytical method is important. Method validation is a process that demonstrates that a method will successfully meet or exceed the minimum standard recommended in the USFDA or other guideline for accuracy, precision, selectivity, sensitivity, reproducibility and stability. 

Keywords: Bioanalytical Method Development; LC-MS/MS; Bioanalytical Method Validation.