Method Development for Quantitative Determination of Ormustine in Biological Fluids by High Performance Liquid Chromatography with Mass-Spectrometric Detection

Abstract

An HPLC method over a Kromasil C18 reversed-phase column with mass spectrometric detection and EtOH:NH₄OAc (10:90) mobile phase was developed for quantitative determination of the antitumor drug ormustine in biological fluids. The method enabled detection of both drug isomers, possessed sufficiently high sensitivity and specificity, and was linear over a wide range. The developed method was used to study ormustine pharmacokinetics in rabbits. It was found that the pharmacokinetics of both drug isomers after i.v. injection followed a two-compartment model. The elimination half-lives of ormustine-I were (3.5 ± 0.2) and (109.4 ± 22.2) min for the α- and β-phases, respectively; of ormustine-II, (3.6 ± 0.2) and (79.5 ± 21.7) min, respectively.