THE DETERMINATION OF BROMAZEPAM IN PLASMA BY REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

A reversed-phase high-performance liquid chromatographic method has be en developed for the determination of bromazepam, an anxiolytic benzod iazepine, in plasma. After a single-step extraction from alkalinized p lasma with diethyl-ether in the presence of an internal standard (alph a-hydroxy-triazolam), the residues were chromatographed on a reversed- phase Nova Pak 5 mum C18 column, with a mobile phase of acetonitrile-w ater-triethylamine (700:300:4, v/v/v) adjusted tq pH 7.4 with orthopho sphoric acid. The limit of detection was 50 ng ml-1, using a 20 mul in jection with UV detection at 240 nm. Between-day and within-day relati ve standard deviations were lower than 6%. Studies of drug stability d uring sample storage at -20-degrees-C and at +4-degrees-C showed no de gradation of bromazepam. However, bromazepam seemed to be degraded at ambient temperature, without any influence of light. This method is ap plied to the determination of bromazepam plasma levels in analytical t oxicology.