Determination of isotretinoin in human plasma: Application to pharmacokinetic study

A simple, rapid, sensitive and accurate HPLC–UV detection method was developed and validated for the determination of isotretinoin in human plasma. The method involves protein precipitation of plasma by acetonitrile using nifedipine as the internal standard (IS). Chromatographic separation was achieved on Agilent C18 column using an acetonitrile: aqueous 0.5% glacial acetic acid (70:30, v/v) mobile phase. Isotretinoin in the eluent was monitored at 350 nm. Inter-assay of the coefficient of variations (CV%) over the range of plasma calibration curves (0.02–0.60 μg/ml) ranged from 2.32% to 6.49% with good correlation coefficient (R^2 =0.999). The average recovery of the extraction procedure was 99.128%. The LLOD and LLOQ are 0.007 and 0.02 μg/ml, respectively. This method was applied for pharmacokinetic study and the results indicated that this method is suitable for pharmacokinetic and bioavailability studies.