Pharmacokinetic behavior of two tablet formulations of mefenamic acid in healthy volunteers

ABSTRACT

The pharmacokinetic behavior of single dose of two mefenamic acid tablet formulations was studied in a randomized cross over design in 19 healthy male volunteers. The two products [Fendol DS and Ponstan Forte] were found similar in weight and content uniformity, however Fendol DS tablets had a faster dissolution rate compared to Ponstan Forte. Following ingestion of 500 mg of either of the products blood samples were obtained over a 14 h period and the serum drug concentrations were determined by an HPL assay with ultraviolet detection at 280 nm. The parametric 90% confidence intervals of the mean value of the ratio [Fendol DS/Ponstan Forte] of Pharmacokinetic parameters were 0.91-1.15, 0.92-1.13,0.92-1.23, and 0.94-1.15 for AUC [0'14h], AUC[0-infinity], C[max] and T[1/2], respectively. In each case values were within the acceptable bioequivalence range of 0.8-1.25. Point estimate of the difference of T [max] between the two formulations [Fendol DS - Ponstan Forte] was 0.16 hours with a 90% confidence interval of -0.33-0.64 which overlaps with the stipulated bioequivalence range of +/- 0.39. The kinetic parameters are comparable to what is reported for mefenamic acid and there were no statistically significant differences in any of them when comparing the two products. Thus, the two products could be considered bioequivalent regarding rate of absorption C [max] and T [max], extent of absorption [C[max] and AUC] and elimination t [1/2]