A quantitative analytical method for the determination of a new thromboxane synthetase inhibitor (CGS 22652) in human plasma using high performance liquid chromatography.

A quantitative analytical method for the determination of a new thromboxane synthetase inhibitor (CGS 22652) in human plasma has been developed using high performance liquid chromatography (HPLC). The drug and internal standard (CGS 23298) were extracted with methylene chloride at pH 4.8. Separations were achieved by reversed phase chromatography using a mobile phase consisting of acetonitrile: 0.01M citrate/phosphate buffer (pH 3.5): methanol: tetrahydrofuran (45:45:9:1, v/v/v/v/), on a 5 μm C18 column at a flow rate of 1.0 mL/min. Plasma standard curves were linear from 50 to 2000 ng/mL, with recovery of the drug being greater than 94% at all concentrations. The method was validated over a concentration range of 50 to 2000 ng/mL, with a limit of quantification of 50 ng/mL. The method was successfully applied to the analysis of clinical samples from a single-dose safety and tolerability study conducted in healthy male volunteers.