AIMTo establish a RP-HPLC method for determination of diphenytriazol (DL111-IT) in rat hepatic microsomes.

METHODSDL111-IT in rat hepatic microsomal incubates was extracted with chloroform, using diazepam as internal standard. The determination was performed on a Lichrospher ODS-C18 reversed column (25 cm x 0.46 cm ID) with mobile phase of methanol-pH 7.5 phosphate buffer (70:30) at a flow-rate of 1.0 mL.min-1. A UVVIS detector was operated at 235 nm.

RESULTSThe assaywas linear from 1.01-101.0 micrograms.mL-1 for DL111-IT. The limit of detection was 0.15 microgram.mL-1 (signal-to-noise ratio 3) and the limit of quantification was 1.01 micrograms.mL-1(RSD < 10%, n = 4). The method afforded average recoveries of (100.3 +/- 1.9)% (n = 5), and intra-day and inter-day RSD were less than 5.0%(n = 5). The method allowed study of the in vitro phase I metabolism of DL111-IT in rat liver microsomal incubates. The microsomes induced by beta-naphthoflavone showed high enzymatic activity for DL111-IT phase I metabolism.

CONCLUSIONThe method is simple, accurate and can be used to study the metabolism of DL111-IT in rat hepatic microsomes.