CHIRAL RESOLUTION OF 4 OPTICAL ISOMERS OF DILTIAZEM HYDROCHLORIDE ON CHIRALCEL COLUMNS BY PACKED-COLUMN SUPERCRITICAL-FLUID CHROMATOGRAPHY

The optical isomers of diltiazem hydrochloride Ca-channel blocker were separated by packed-column sub-and/or supercritical fluid chromatogra phy (p-SubFC and/or p-SFC) on a column of modified cellulose coated on to silica, using a mixture of carbon dioxide with a polar modifier and additive. The effect of parameters (Chiralcel columns, modifiers, add itive, pressure and temperature) was investigated systematically, and the interactions between the diltiazem optical isomers and chiral stat ionary phase were discussed, Four optical isomers of diltiazem hydroch loride were achieved with baseline resolution on the Chiralcel OD colu mn within 8 min. To determine three optical impurities in diltiazem hy drochloride, the precision, accuracy, linearity and detection limit we re investigated, and the results were sufficiently acceptable. In addi tion, the resolutions in p-SFC were compared with those in high-perfor mance liquid chromatography. (C) 1997 Elsevier Science B.V.