Enantiomeric separation of verapamil and norverapamil using Chiral-AGP (R)as the stationary phase

Simultaneous enantiomeric separation of verapamil and its main metabolite n orverapamil was achieved using Chiral-AGP as the stationary phase. The opti mized chromatographic system was obtained using statistical experimental de sign with partial least squares as regression method. The three variables s tudied were buffer pH, content of acetonitrile and column temperature. A hi gh buffer pH favors enantioselectivity as well as the selectivity between ( S)-verapamil and (R)-norverapamil. The concentration of the organic modifie r in the mobile phase was a compromise as a high content of acetonitrile de creased enantioselectivity but increased the selectivity mentioned above. I ncreased column temperature increased the separation between (S)-verapamil and (R)-norverapamil with only a slight decrease in enantioresolution. (C) 1999 Elsevier Science B.V. All rights reserved.