The bioavailability of commercial metronidazole formulations.

A bioavailability study of eight commercial pharmaceutically equivalent tablet formulations and a solution of metronidazole was conducted in groups of ten subjects with single oral 250 mg doses. Although the solution gave significantly lower extents of bioavailability, the commercial tablets were not significantly different from the (innovator) reference product. The slow rate of absorption for one formulation (F) was observed to be associated with long dissolution time. Individual elimination half-life differences (probably attributable to metabolism) were reflected in considerable intersubject differences in plasma metronidazole concentrations.