Determination of deflazacort in human plasma by liquid chromatography-mass spectrometry after liquid-liquid extraction and its application in human pharmacokinetics studies

PURPOSE: A sensitive liquid chromatography-mass spectrometric (LC/MS) has been developed and validated for the quantification of deflazacort in human plasma after liquid-liquid extraction (LLE). MATERIALS AND METHODS: Best chromatographic resolution was achieved on a reverse-phase Phenomenex C(18) column with the mobile phase of acetonitrile–water (30:70) and isocratic elution resulted in a total run time of about 3.5 min. The analyte was detected by using an electrospray positive ionization mass spectrometry in the selected ion monitoring (SIM) mode. Linearity was obtained in the concentration range studied (5–150 ng/ml) (r = 0.9974). RESULTS: Lower limit of quantification (LLOQ) was found to be 5 ng/ml in 500μl plasma sample. Average recovery of the analyte was found to range from 86.80 to 88.19% in plasma at the concentrations of 15.0, 60.0 and 120.0 ng/ml. CONCLUSIONS: The present method was successfully applied in the pharmacokinetic study of deflazacort in human plasma.