Bioavailability of sustained release indomethacin suppositories containing polycarbophil

Abstract

The bioavailability of indomethacin from polyethylene glycol base, commercial suppositories Indocid ∗, MSD and from polyethylene glycol base containing 5, 6 and 8% of polycarbophil, with the purpose of obtaining a controlled release suppositories, was determined in dogs. The results show that polycarbophil as a bioadhesive increased absorption and improved the bioavailability of indomethacin where the areas under the curves for the commercial suppositories and those containing 0, 5, 6 and 8% polycarbophil were 19.5, 14.9, 31.2, 21.4 and 21.2 μ h ml −1, respectively. The maximum plasma concentration ( C max) and the time to reach C max ( t max) were 4.76, 2.98, 4.50, 2.36 and 1.29 μg/ml and 1, 1, 1, 1 and 12 h for the commercial suppositories and those containing 0, 5, 6 and 8% polycarbophil, respectively. The data indicate that as the polycarbophil concentration increased from 0 to 5% in the polyethylene glycol suppositories, the plasma levels and bioavailability improved significantly ( p < 0.1, Student's t-test), whereas on increasing from 5 to 6 and 8% the plasma levels and bioavailability decreased significantly ( p < 0.05). At 8% polycarbophil concentration, sustained release suppositories were produced but a decrease in plasma levels was observed.