Clinofibrate

A highly sensitive and rapid liquid chromatography-tandem mass spectrometry method was developed for the determination of clinofibrate in human urine. The analyte and IS were extracted through a simple protein precipitation by the mixture of acetonitrile and 1 mol/L hydrochloric acid (95:5, v/v) and separated on an Inspire C18 (150 mm x 4.6 mm I.D., 5 μm particle size) column using isocratic elution with methanol and water containing 0.1% formic acid and 10 mM ammonium acetate (90:10, v/v). Mass spectrometric detection was performed in electrospray positive ionization MRM mode. The mass transition was m/z 486.3-->175.0 for clinofibrate and m/z 361.1-->233.1 for IS, respectively. The flow rate was 0.6 mL/min and the column oven temperature was set at 35 °C. The total run time was 6.5 min. Good linear relationships were obtained for all analytes over the concentrations ranging of 0.1002-10.02 μg/mL (r2 = 0.9991) and the limit of quantification was 0.1002 μg/mL. The extraction recovery was larger than 87.4% and intra- and inter-batch precision and accuracy with RSD were all less than 6.5%. The total amount of unchanged clinofibrate excreted in urine was less than 0.34%. This method was successfully applied to the pharmacokinetic study of clinofibrate in human urine.

The aim of this study is to investigate a food effect on the single-dose pharmacokinetics and tolerability of clinofibrate tablets in 12 Chinese healthy volunteers. The authors evaluated the effect of being under a fasting or fed state at the time of drug intake on the single-dose of clinofibrate 400 mg tablets in a randomized, balanced, single-dose, two-treatment (fed and fasting), two-period, two-sequence study design with a 7-day washout period. The end points were the maximum plasma drug concentration (Cmax) and areas under the plasma-concentration curve (AUC) for 72 hours exposure (AUC0-72) and total exposure (AUC0-∞). All participants completed the whole study without side effects being observed. The Cmax mean of clinofibrate glucuronides and parent clinofibrate were 21.91, 17.85 μ/ml for the fasting state and 13.14, 11.25 μ/ml for the fed state, respectively. The AUC0-72 and AUC0-∞ of clinofibrate glucuronides and parent clinofibrate were 381.60, 307.07 μ/ ml and 404.55, 342.24 μ/ml for the fasting state and 379.02, 321.14 μ/ml and 432.24, 351.80 μ/ml for the fed state. The authors showed that food intake was associated with a significant decrease in Cmax, but no significant change in AUC values.