SPECTROPHOTOMETRIC ASSAY OF CERTAIN BENZODIAZEPINE DRUGS THROUGH COMPLEX FORMATION REACTION

Document Type : Original Article

Authors

Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Assiut, Assiut, Egypt

Abstract

A simple and accurate spectrophotometric method was developed for the determination of diazepam, prazepam and flunitrazepam. The method is based on the interaction of the benzodiazepine drug containing an active methylene group with 1,3-dinitrobenzene in presence of tetraethylammonium hydroxide to form a violet coloured d-complex (lmax=560 nm). Beer's law is obeyed over the concentration ranges 2-20 mg ml-1 (for diazepam), 5-30 mg ml-1 (for prazepam) and 5-40 mg ml-1 (for flunitrazepam). The method was successfully applied to the assay of the cited drugs in pure form and in pharmaceutical formulations. Results obtained agree well with those of official methods.