Separation of cis-β-lactam enantiomers by capillary electrophoresis using cyclodextrin derivatives

Chiral separation of 19 pairs of cis-β-lactam (BL) stereoisomers of pharmacological importance was examined by capillary electrophoresis using cyclodextrin (CD) derivatives. In order to select the most effective conditions separating the highest number of stereoisomers of BLs, single carboxymethyl α-, β- and γ-, as well as sulfobutyl β-CD derivatives were applied. Additionally, carboxymethyl and sulfobutyl β-CD derivatives complemented with neutral β-CD derivatives as dual CD systems were tested. Both the composition and concentration of applied selectors and the pH of background electrolyte were selected. In single systems the structural characteristics of BLs and the complex forming affinity were correlated. Most BLs provided optimal complexation with β-CD derivatives. In conclusion, the efficiency of combining sulfobutyl-β-CD and permethylated β-CD was superior to other single and dual CD systems applied. This method successfully separated each pair of stereoisomers investigated.