Wen Aidong

A simple high-performance liquid chromatographic method for the determination of brazilin and its application to a pharmacokinetic study in rats

ETHNOPHARMACOLOGICAL RELEVANCE Caesalpinia sappan is a medicinal plant native to China popularly used to treat chronic pelvic inflammation, dysmenorrhea and hysteromyoma. Its main bioactive component is brazilin which had presented antibacterial, anti-inflammatory and anti-platelet aggregation activities. To establish a sensitive, selective, reproducible, and accurate high performance liquid chromatographic (HPLC) method for the quantitative determination of brazilin in plasma, and study the pharmacokinetics of brazilin in rats after intravenous administration of brazilin. MATERIALS AND METHODS Rats received intravenous injection of 25, 50 and 100mg/kg of brazilin. Concentrations of brazilin in plasma were determined by HPLC method at different time points and all pharmacokinetic parameters were estimated by non-compartmental analysis with WinNonLin 6.2 software. RESULTS After single intravenous doses of 25, 50 and 100mg/kg brazilin in rats, the main PK parameters were as follows: Cmax were 18.1 ± 4.1, 46.7 ± 8.7 and 82.2 ± 9.6 µg/mL; AUC0-24 were 20.4 ± 4.3, 48.7 ± 6.8 and 90.4 ± 10.3 µgh/mL; and t1/2 were 5.4 ± 1.5, 5.8 ± 0.9 and 6.2 ± 1.2h, respectively. CONCLUSION It showed that the brazilin was eliminated moderately in rat by intravenous injection route with t1/2 of 6h and showed a dose-dependence profile of Cmax and AUC0-24 at the doses of 25~100mg/kg of brazilin for injection in rats.

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

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 1M hydrochloric acid (95:5, v/v) followed by separation using an Inspire C(18) column with isocratic elution. The detection wavelength was 232nm and the flow rate was 1.0ml/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 0.5μg/ml to 32μg/ml (r(2)=0.999) with LLOQ of 0.5μg/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 600mg clinofibrate, respectively. The results of WinNonlin software showed that the area under the plasma concentration versus time curve from time 0 to 72h (AUC(0-72)) and peak plasma concentration (C(max)) were linearly related to dose (P>0.05).

High-Performance Liquid Chromatographic Analysis of Felotaxel, a Novel Anti-Cancer Drug, in Rat Plasma and in Human Plasma and Urine

A high-performance liquid chromatographic method was developed for the determination of a new derivative of docetaxel, felotaxel, in rat plasma and human plasma and urine. The separation of felotaxel was performed on a Dikma C18 column with 0.2% formic acid and acetonitrile (50:50) as the mobile phase. The flow rate was 0.8 mL/min and the column effluent was monitored by an ultraviolet detector set at 275 nm. The method was validated and found to be linear in the range of 5-1,000 ng/mL. The lower limit of quantification was 5 ng/mL based on 100 µL of plasma. The variations for intra-day and inter-day precision were less than 6.9%, and the accuracy values were between 87.3 and 107.4%. The extraction recoveries were more than 80.5%. These data confirm that the developed method has satisfactory sensitivity, accuracy and precision for the quantification of felotaxel in rat plasma and in human plasma and urine. The method was successfully applied to a pharmacokinetics study of felotaxel after intravenous doses of 5 mg/kg in rats.