High-performance liquid chromatographic method for determination of clinofibrate and its application to a pharmacokinetic study in healthy volunteers

Abstract A convenient and rapid HPLC method was developed for the determination of clinofibrate in human plasma using simple protein precipitation with the mixture of acetonitrile and 1 M hydrochloric acid (95:5, v/v) followed by separation using an Inspire C 18 column with isocratic elution. The detection wavelength was 232 nm and the flow rate was 1.0 ml/min. The mobile phase consisted of acetonitrile and water containing 0.4% ortho-phosphoric acid (73:27, v/v). Linear calibration curve was obtained over the concentrations ranging from 0.5 μg/ml to 32 μg/ml ( r 2  = 0.999) with LLOQ of 0.5 μg/ml. The RSD in both the intra-run and inter-run precision study was less than 5.4% and the extraction recoveries were above 90.7%. The HPLC method is reproducible and suitable for the quantification of clinofibrate in plasma. This method was successfully applied to the pharmacokinetic studies of clinofibrate in healthy volunteers. The elimination half-lives ( t 1/2 ) were (20.47 ± 3.44), (18.19 ± 2.62) and (21.51 ± 4.78) h after single oral administration of 200, 400 and 600 mg clinofibrate, respectively. The results of WinNonlin software showed that the area under the plasma concentration versus time curve from time 0 to 72 h (AUC 0–72 ) and peak plasma concentration ( C max ) were linearly related to dose ( P  > 0.05).