Inclusion complex formation of anti-inflammatory drug biphenyl acetic acid (BA) with β-cyclodextrin (β-CyD) in water and in solid state was assessed by solubility method and powder X-ray diffractometry. The release of BA from suppository base in saline was significantly increased by the β-CyD complexation. The serum level of BA after the rectal administration in complex form to rats was higher than that of the drug alone. No appreciable change in irritation of the complex on rectal membrane in rats was obserbed in comparison with that of the drug alone in spite of the increase of bioavailability. The present data suggested that β-CyD seems to be useful for improving the pharmaceutical properties of BA in suppository formulation.
