Abstract: Several hydroxypropyl-β-cyclodextrins (HP-β-CDs) with various degree of substitution and different positi0n of substituti0n were synthesized.The average degree of substi-tution (D_s) of HP-g-CDwere determined by fast atom bombardment mass spectrometry(FAB-MS).The effects of the D_s of HP-β-CD on CEres0lution of four basic drugs werestudied.The results show that Ds has a different effects on the separation of various drugsbecause of different molecular structures.At D_s=0(β-CD), no separation was found for isoproterenol, of loxacin and propranolol.The resolution of both isoproterenol and ofloxacin in-creased with the increase of Ds, but decreased when D_s was 14.The best reso1ution was at D_s=10.2.The resolution of propranolol increased with increasing D_s.In contrast, the resolution of chlorophiramine decreased with the increase of D_s.The effects of the position ofsubstitution of HP-β-CDon separations were also investigated- The results demonstrate thatthe substitution at the second position of CDplays an important role in the separation ofenantiomers- ln general, the more substitution at the second position of CD, the better theseparation was obtained because the substitution of the second position made the wide open-ing become wider- This probably makes it easier for some molecular to enter the cyclodextrincavity, which c0uld facilitate enantiomeric separation.

Key words: Capillary electrophoresis, Chiral separations, Hydroxypropyl-β-cyclodextrin, Basic drugs