SEPARATION OF LISINOPRIL AND ITS RSS DIASTEREOISOMER BY MICELLAR ELECTROKINETIC CHROMATOGRAPHY

Diastereoisomer separation of pharmaceuticals having several chiral centers by capillary electrophoresis is exemplified by the separation of lisinopril (SSS) (an inhibitor of angiotensin converting enzyme) from its RSS diastereoisomer. Using micellar electrokinetic capillary chromatography (MECC), excellent resolution between the two diastereoisomers was achieved by using a bile salt, sodium cholate, as the surfactant in electrolyte under optimized pH, organic content and temperature conditions. The RSS compound eluted earlier than the SSS compound. A good separation was also achieved by the use of sodium dodecyl sulfate (SDS) as a surfactant in electrolyte, but the eluting sequence was reversed, resulting from the different hydrophobic/hydrophilic nature of the two surfactants.