Diazepam is an important drug from the group of benzodiazepines, used in clinical practice for its sedative, hypnotic, anticonvulsive, myorelaxant, and primarily anxiolytic effects. Several kinetic studies have been published which show that diazepam is a drug sensitive to hydrolysis both in acid and alkaline media. The present study aimed to elaborate and validate a simple and rapid HPLC/UV method for simultaneous analysis of three decomposition products of diazepam in the presence of diazepam and to apply it also on the control of stability of the injectional solution of diazepam. The optimization of chromatographic conditions resulted in the use of the high-performance chromatographic column Zorbax ODS, the mobile phase represented by a mixture of acetonitrile/water in a ratio of 60/40 (w/w, %), flow rate 1.5 ml/min, and spectrophotometric detection at 242 nm. The elaborated method and the employed chromatographic systemwere successfully validated and they can be used in practice in the control of stability of injection solution of diazepam.

        Key words: HPLC/UV – diazepam – 2-amino-5-chlorobezophenone – 2-methylamino-5-chlorobezophenone – 3-amino-6-chloro-1-methyl-4-phenylcarbostyril – validation