Use of cyclodextrins in capillary electrophoresis for the chiral resolution of some 2-arylpropionic acid non-steroidal anti-inflammatory drugs

The enantiomeric separation of racemic compounds of some 2-arylpropionic acid non-steroidal anti-inflammatory drugs (profens), namely fenoprofen, ibuprofen, flurbiprofen, suprofen, ketoprofen and indoprofen, was performed by capillary zone electrophoresis. The separation was obtained by supporting the background electrolyte with derivatized ?-cyclodextrins. The type and concentration of cyclodextrin used and the background electrolyte composition (pH and amount of methanol) influenced the complexation and the chiral resolution. All the modified ?-cyclodextrins used (heptakis-2,6-di-O-methyl-?-, heptakis-2,3,6-tri-O-methyl- and 6(A)-methylamino-?-cyclodextrin) showed good complexing effects with the profens tested. Tri-O-methyl-?-cyclodextrin proved to be the best stereoselective additive because it allowed the enantiomeric resolution of all the profens studied whereas the dimethylated and methylamino-?-cyclodextrin were able to separate only some of them.