Chiral analysis of metoprolol and its by-products by capillary electrophoresis

The enantiomers of metoprolol, a frequently used beta-blocker, have differe nt physiological effects, which makes their chiral separation necessary. Th e separation of the main product from its by-products and their chiral sepa ration were also aims of this study. Capillary electrophoresis (CE) with cy clodextrin (CD) additives, providing high efficiency and selectivity, was a pplied for this goal. Separation of the main product from 5 by-products as well as their chiral separation was realized. Fifteen CDs (native alpha, be ta, gamma, and derivatives) were evaluated. Carboxymethylated alpha-CD (R-s 3.0), and phosphated alpha-CD (R-s 2.7) were the best for the chiral separ ation of metoprolol while carboxymethylated alpha-CD, phosphated alpha-CD, and phosphated gamma-CD were appropriate for the enantioseparation of bypro ducts and for their separation from the main product. The roles of the type and concentration of the chiral selectors, of the pH, and of the organic a dditives in the buffers were studied. The stacking effect of phosphated alp ha-CD was investigated in detail. (C) 1999 John Wiley & Sons, Inc.