High Performance Liquid Chromatographic Determination of Triazolam in Human Serum

A high performance liquid chromatographic method which utilizes UV-detection has been developed for the sensitive and specific determination of triazolam in human serum. Using 8-chloro-6-phenyl-l-ethoxymethyl-4H-s-triazolo[4, 3-a][1, 4]benzodiazepine as an internal standard, serum samples were buffered with 2 ml of 4M NaOH and extracted twice with 5 ml aliquots of toluene. The combined toluene extracts were evaporated to dryness and the residue dissolved in the chromatographic mobile phase. The samples were chromatography on a microparticulate reverse-phase column using a 0.06M acetic acid:acetonitrile (61:39) mobile phase. Known metabolites of triazolam did not interfere in the analysis. A linear relationship between peak height ratios and concentrations was observed, with the lower limit of detection being approximately 1 ng of triazolam. The utility of the method was demonstrated by administering therapeutic doses of the drug to human volunteers and monitoring serum triazolam concentrations as a function of time.