DIRECT AND INDIRECT APPROACHES TO ENANTIOMERIC SEPARATION OF BENZODIAZEPINES USING MICRO COLUMN TECHNIQUES

The ability of gas chromatography, supercritical fluid chromatography (SFC) and subcritical fluid chromatography to separate ten benzodiazepine racemates, using both direct and indirect methods, has been investigated. Racemic lorazepam, oxazepam, ethyl loflazepate and dihydrodiazepam were baseline separated in open tubular column SFC using a permethylated beta-cyclodextrin stationary phase. Racemic oxazepam, lorazepam, temazepam and ethyl loflazepate, derivatized with (S)-trolox methyl ether, were separated on a non-chiral packed capillary column with diol functionality, employing a subcritical fluid as mobile phase. The temazepam derivatives were also baseline separated using an open tubular biphenyl column in SFC.