Relative bioavailability of etofibrate. A comparison of an acute and a new sustained release formulation.

The relative bioavailability of 2-(p-chlorophenoxy)-2-methylpropionic acid [2-(nicotinyloxy)-ethyl]-ester (etofibrate) from Lipo-Merz retard (500 mg) with respect to Lipo-Merz (600 mg) has been determined in 10 health volunteers in a crossover study. Etofibrate was determined in plasma after hydrolysis to clofibrinic acid. Pharmacokinetic parameters were derived to describe the plasma concentration-time profiles using a minimisation of least squares technique. The absorption was apparently delayed following the sustained release formulation with a longer time to maximum plasma concentration, which was significantly lower following the retard form. No significant differences were found in the mean apparent elimination half-lives nor areas under the plasma concentration-time curves indicating that the two formulations can be considered bioequivalent.