Quantitative analysis of minaprine and some of its metabolites with application to kinetic studies in rats

A simple and rapid high-performance liquid chromatographic method is described for the quantitative analysis of the psychotropic drug minaprine and three of its metabolites (M₁, M₃ and M₁₁), including one as yet undetected metabolite (M₁₁) known as a monoamine oxidase type A inhibitor in vitro. After selective extraction all four compounds were separated on a reversed-phase μBondapak C₁₈ column using sodium acetate (0.03 M)-acetonitrile-methanol (88:7:5) (pH 3.3) as the mobile phase. The eluted compounds were detected with a UV detector at 254 nm. The sensitivity of the method is 0.02 μg per millilitre of body fluid or per gram of tissue for M₁ and M₁₁ and 0.05 μg for minaprine and M₃. The method has been applied successfully to the determination of minaprine and the metabolites in plasma and brain and is compared here with an gas-liquid chromatographic method with an electron-capture detector previously developed for the detection of minaprine and M₁₁. M₁₁ was identified in rat urine by gas chromatography-mass spectrometry.