DIRECT CHROMATOGRAPHIC RESOLUTION OF 4 OPTICAL ISOMERS OF DILTIAZEM HYDROCHLORIDE ON A CHIRALCEL OF COLUMN

Diltiazem hydrochloride is a calcium channel blocker which is administered as a single enantiomer. The direct resolution of four optical isomers of diltiazem hydrochloride was studied on both normal- and reversed-phase chiral HPLC columns. Four optical isomers of diltiazem hydrochloride were completely resolved on a Chiralcel OF column within 30 min. This chiral resolution was applied to determine three optical impurities that might be present in diltiazem hydrochloride bulk drug and its tablets. The determination of three optical impurities in the diltiazem hydrochloride bulk drug and those in tablets was successfully achieved at levels down to 0.05% by the area percentage method.