Improvement of dissolution and suppository release characteristics of flurbiprofen by inclusion complexation with heptakis(2,6-di-O-methyl)-beta-cyclodextrin.

The inclusion behavior of methylated beta-cyclodextrins, heptakis(2,6-di-O-methyl)-beta-cyclodextrin and heptakis-(2,3,6-tri-O-methyl)-beta-cyclodextrin in solution and the solid state was compared with that of natural beta-cyclodextrin using an anti-inflammatory drug, flurbiprofen, as a guest molecule. Stability constants were determined by the solubility method at various temperatures, and the thermodynamic parameters were calculated for inclusion complex formation in aqueous solution. The solid complexes were obtained in a molar ratio of 1:1, and their dissolution behavior and release from suppository bases were examined. The data suggest that the inclusion mode of the complex with 3 is somewhat different from that of the complexes with 1 and 2. From a practical point of view, 2 seems to be particularly useful for improving the pharmaceutical properties of flurbiprofen in various dosage forms.