Enantioselective enzymatic biotransformation of 2'-deoxy-3'-thiacytidine (BCH 189) monitored by capillary electrophoresis.

Concentrations of the enantiomers of 2'-deoxy-3'-thiacytidine (BCH 189) have been monitored during enantiospecific biotransformation catalyzed by cytidine deaminase. This enzymatic reaction is monitored by capillary electrophoresis (CE) over a 51-h time period. The use of dimethyl-beta-cyclodextrin as a chiral electrolyte additive in a pH 2.3 phosphate buffer system gives enantiomeric separation with results for peak efficiencies, resolution, and analysis time of the order of 25,000 plates, > 1.5 and 30 min, respectively. The features of the CE method are compared with those of the previously favored chiral HPLC method.