Regioselective synthesis of cyclodextrin mono-substituted conjugates of non-steroidal anti-inflammatory drugs at C-2 secondary hydroxyl by protease in non-aqueous media.

Three beta-cyclodextrin (beta-CD) conjugates of non-steroidal anti-inflammatory drugs were synthesized by enzymatic methods. Transesterification of beta-CD with vinyl ester of indomethacin, ketoprofen and etodolac was performed by the catalysis of alkaline protease from Bacillus subtilis in anhydrous DMF for 3 days. The drug molecules were selectively conjugated onto one of the secondary hydroxyl groups of beta-CD through ester-linkage to improve their poor water solubility and absorption characteristics. The products were characterized by ESI-MS, (1)H NMR and (13)C NMR. The structures of products with monoacylation occurring at the C-2 secondary hydroxyl groups of beta-CD were confirmed.