The enantiomeric separation of chiral drugs mexiletine and verapamil was investigated using cyclodextrins added buffers at acidic conditions in capillary zone electrophoresis. The results show that the type and concentration of chiral selector, buffer concentration etc, influence the separation. Among the five cyclodextrins (CDs) investigated, i.e., α-CD, β-CD, Heptakis(2, 6-di-O-methyl)-β-CD (DM-β-CD), Hydroxypropyl-β-CD(HP-β -CD) and γ-CD, HP-β-CD gave the best separation of verapamil and mexiletine is at 9 and 30 mmol/L, respectively and the optimal Tris-H3PO4 (pH 2.3) buffer concentration at 100 mmol/L. The separation was improved by the addition of 0.05% hydroxypropyl cellulose (HPC) to the buffer. Under the optimized separation conditions, near baseline enantiomeric separation was achieved for mexiletine and enantiomers of verapamil were also fairly well separated.

Key words: SEPARATION, CYCLODEXTRIN, ENANTIOMORPH, CAPILLARY ZONE ELECTROPHORESIS