A validated high-performance liquid chromatography method for the determination of rifampicin and desacetyl rifampicin in plasma and urine

Objective: To standardize a high-performance liquid chromatography (HPLC) method for the determination of rifampicin (RMP) and its major metabolite desacetyl rifampicin (DRMP) in plasma and urine. Material and Methods: A simple, specific and sensitive HPLC method was developed for the determination of RMP and DRMP in plasma and urine. Separation in both was achieved by reversephase chromatography on a C 18 column with a mobile phase composition of 0.05 M phosphate buffer: acetonitrile (55:45 v/v) at 254 nm. Results: The retention times of DRMP, RMP and Rifapentine (RPN), the internal standard were 2.9, 4.8 and 10.5 min respectively. The assay was linear from 0.25 to 15.0 μg ml for plasma and 2.5 to 80.0 μg ml for urine. Both intra-day and inter-day accuracy and precision data showed good reproducibility. Conclusion: The HPLC method described is sensitive, selective and linear for the wide range of concentrations for RMP and DRMP in plasma and urine. Thus, the method developed is well suited for the pharmacokinetic studies.