Polarographic method for the identification of 1,4-benzodiazepines

Abstract

The polarographic behaviour of 12 therapeutically important 1,4-benzodiazepines in Britton-Robinson universal buffers, pH 4.0 and pH 12.0, has been investigated. Differences in the polarographic peak potentials of these compounds in these media are explained. The rates of hydrolysis of certain benzodiazepines in acidic solution were investigated. Bromazepam and flunitrazepam, both of which possess a strongly electron-withdrawing substituent on the 5-o-phenyl group, were found to undergo rapid acid hydrolysis. On the basis of these findings, and taking into account the extraction profile of some of the compounds over a pH range, a scheme is devised for the identification of any one or more of 12 1,4-benzodiazepines. It is suggested that this procedure would be applicable to the analysis of unknown formulations or body fluids in forensic cases where the parent compound exists in relatively high concentrations compared with its metabolites.