DETERMINATION OF THE ANTI-PLATELET-ACTIVATING FACTOR BN-50727 AND ITSMETABOLITES IN HUMAN PLASMA BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHYSOLID-PHASE EXTRACTION

A sensitive and selective HPLC-solid-phase extraction procedure was de veloped for the determination of platelet-activating factor antagonist BN-50727 and its metabolites in human plasma. The procedure consisted of an automated solid-phase extraction of the drug and metabolites on disposable propylcarboxylic acid cartridges, followed by on-line chro matographic separation. The method was linear from 3.75 to 2400 ng/ml and the limit of quantitation for BN-50727 in plasma samples was 3.75 ng/ml. The within-run precision of the method, expressed as relative s tandard deviation, ranged from 2.1 to 8.1%. The accuracy, expressed as relative error, ranged from -3.5 to 4.0%. For the main metabolite, th e O-demethylated BN-50727 product, the method was linear from 7.5 to 2 400 ng/ml and the limit of quantitation in plasma was 7.5 ng/ml. The w ithin-run precision ranged from 2.1 to 11.0%:, and the accuracy from - 5.3 to 1.1%. This paper describes the validation of the analytical met hodology for the determination of BN-50727 in human plasma and also of its metabolites. The method has been used to follow the time course o f BN-50727 and its metabolites in human plasma after administration of single and multiple doses.