The bioavailability of flufenamic acid from aluminum flufenamate tablet and flufenamic acid capsule, and the influence of food and aluminum hydroxide gel.

The bioavailabilities of flufenamic acid (I) from a commercial aluminum flufenamate (II) tablet and I capsule were estimated by measuring urinary excretion of I and its metabolites fluorometrically. The dissolution rates of I from both dosage forms were also determined. The effects of concomitant intake of food or antacid on the bioavailabilities from the II tablet and the I capsule were investigated. The extent on I bioavailability from the II tablet was less than 30% of that from the I capsule. Dissolution tests suggested that the low bioavailability of I from II tablet resulted from the extremely slow release of I from the II complex. Intake of a standard meal retarded I absorption from I capsule, but did not affect that from the II tablet. Ingestion of dried aluminum hydroxide gel granules had little effect on I bioavailability from the I capsule.