PREFORMULATION STUDIES ON MEFENAMIC-ACID - EFFECT OF CERTAIN ADDITIVES AND TECHNIQUES ON THE DISSOLUTION AND BIOAVAILABILITY OF MEFENAMIC-ACID CAPSULE AND TABLET FORMULATIONS

In this study the effect of different concentrations of polyethylene glycol (PEG), either alone or in presence of avicel, as well as various techniques, namely physical mixture (a), coprecipitation (b), flash evaporation (c) and fluidized bed (d), on the dissolution and bioavailability of mefenamic acid formulated capsules and tablets, was investigated. The increase of PEG ratio in capsules prepared by the techniques a, b, and c, was followed by a corresponding increase in the dissolution of the drug. Dissolution results from capsule and tablet formulations containing drug-PEG, avicel showed the following order 1:2:2 > 1:1:1 > 1:0.5:0.5. Techniques c and d showed the best dissolution results because the drug is successfully layered on the avicel core in a fine state with a large specific surface area. Plasma concentrations reached the maximum levels 1.5, 2 and 3 h after administration of the proposed capsules, tablets and convential commercial capsules respectively. Peak heights were 52.4 +/- 2.3, 43.6 +/- 2.6 and 37.2 +/- 3.1-mu-g/ml, while AUC (0-12 h) values were 310.98, 306.99 and 269.15-mu-g/ml.h.