High-performance thin-layer chromatographic detection of 1,4-benzodiazepines

摘要

Owing to their varied properties [1-3] the benzodiazepines are widely used as psychotherapeutic drugs in the treatment of nervous diseases such as anxiety, insomnia, and epileptic convulsions. They are also used to treat of alcohol withdrawal and torelieve pre-operative tension. Because of their ready availability, the benzodiazepines are frequently encountered in forensic work - both drug overdoses and criminal cases; a rapid and sensitive method for their characterization and determination in forensic samples and biological material is, therefore, required. Methods suitable for the analysis of benzodiazepines in their dosage forms and in biological samples include spectrophotometry [4-9], HPLC [10-13], GLC [14,15], polarography [16,17], voltammetry [18-20], potentiometry [21], difference spectrophotometry [22,23], fluorimetry [24], and TLC [25-32]. Several workers [1-5,25] have hydrolyzed the compounds under strongly acidic conditions and then reduced the products with SnCl_2-HCl or Zn-HCl reagents [33] at elevated temperatures for ca 2 h to convert the benzodiazepines into their corresponding 2-aminobenzophenones. Vorweij et al. [31] reported the heat-induced conversion of N-alkylaminobenzophenones into aminobenzophenones on TLC plates.