Development and Validation of Liquid Chromatography-Mass Spectrometry Method for the Estimation of Rifampicin in Plasma

A selective, rapid and sensitive liquid chromatography-mass spectrometry method was developed for the quantitative estimation of rifampicin in plasma. With phenacetin as internal standard, sample pretreatment involved a one-step extraction with ethyl acetate from plasma. The sample was analyzed using methanol: 2mM ammonium acetate: 80:20 v/v as mobile phase. Chromatographic separation was achieved on a BDS Hypersil Gold C(18) column which was followed by detection with mass spectrometry. Linear calibration curves were obtained in the concentration range of 5.021-1008.315 ng/ml. The inter- and intra-day accuracy values were below 15% at all quality control levels. Percent recoveries for rifampicin at high, middle and low quality control samples was obtained 55.15, 48.65 and 49.62%, respectively and for internal standard was 60.22%. Rifampicin was found stable through all validation parameters. Developed method was found to be simple, precise, accurate and rapid for estimation of rifampicin in plasma. Thus, the method can be employed for routine pharmacokinetic and bioequivalence studies.