Racemation of the benzodiazepines camazepam and ketazolam and receptor binding of enantiomers
Blaschke, G.; Kley, H.; Müller, W.E.
Arzneimittel-Forschung 36(6): 893-894
1986
ISSN/ISBN: 0004-4172 PMID: 2874815 Document Number: 280205
The chiral benzodiazepines camazepam (1) and ketazolam (2) were resolved into the enantiomers by chromatography on the optically active adsorbent poly[(S)-N-(1-cyclohexylethyl)-methacrylamide] and fractional crystallisation or repeated chromatography, respectively. The IC50 values of the isomers and of the racemates of both compounds were determined by displacement of radioactively labelled 3H-flunitrazepam and 3H-propyl-beta-carboline-carboxylate from their specific binding sites. (+)-Camazepam exhibits 14fold higher affinity compared to the (-)-enantiomer. In contrast only slight differences in the receptor affinity are observed with the ketazolam enantiomers.