A SELECTIVE FLUOROMETRIC METHOD FOR THE DETERMINATION OF SOME 1,4-BENZODIAZEPINE DRUGS CONTAINING A HYDROXYL GROUP AT C-3

A highly selective and sensitive fluorimetric method was developed for the determination of four 1,4-benzodiazepine drugs containing a hydro xyl group at carbon 3, namely oxazepam, lorazepam, cinolazepam and tem azepam. The method is highly specific because other benzodiazepinee la cking the hydroxyl group at C-3 do not react similarly and hence do no t interfere. The proposed method involves reduction of the target comp ound using Zn degrees/HCl at room temperature with the formation of a highly fluorescent derivative within 15 min. The different experimenta l parameters were carefully studied and incorporated into the procedur e. Under the described conditions, the proposed method is applicable o ver the concentration range of 0.1-1.2 mu g ml(-1) for both temazepam and cinolazepam, and 0.2-2.5 and 1-8 mu g ml(-1) for oxazepam and lora zepam respectively. The recoveries of the title compounds from spiked urine ranged from 90.0 to 92.0% and for serum from 94.1 to 95.4% with a limit of detection (SIN = 2) of 4 ng ml(-1) for all drugs. The mecha nism of the fluorimetric reaction is discussed.