Effects of food on absorption of mefenamic acid from two commercial capsules differing in bioavailability under the fasting state.

The influence of food on the bioavailability of mefenamic acid from two commercial capsules (products A and B) differing in bioavailability was studied with four healthy male volunteers. The drug was administered as a single oral dose of 250 mg under fasting and nonfasting conditions. The study used a 4 X 4 Latin-square design. Seven blood samples were collected over a 9-h period following administration and the plasma concentrations of mefenamic acid were determined by a high performance liquid chromatographical method. The bioavailability was significantly different between the two products in the fasting condition, agreeing with the result of an in vitro dissolution study. However, in the nonfasting state, the difference was not significant because the product showing poor bioavailability, product A, in the nonfasting state showed marked improvement. On the other hand, the product showing good bioavailability, product B, was not affected by food.