Apparent absorption kinetics of micronized griseofulvin after its oral administration on single- and multiple-dose regimens to rats as a corn oil-in-water emulsion and aqueous suspension.

This investigation was designed to quantitate and compare in the rat the oral absorption characteristics of micronized griseofulvin from a corn oil-in-water emulsion dosage form containing suspended drug and a control aqueous suspension after single-dose (50 mg/kg) and multiple-dose (50 mg/kg every 12 hr for five doses) administrations. The time course of intact drug in the plasma of all animals was best described by a one-compartment open model with apparent zero-order absorption. In contrast to that observed with the aqueous suspension, the onset of drug absorption after single-dose administration of the corn oil emulsion was significantly delayed. This difference disappeared upon multiple dosing of the two dosage forms, with the mean onset being quite rapid in both cases. Administration of a single dose of the antibiotic as the corn oil emulsion resulted in considerable increases in the maximum plasma levels of griseofulvin and in the duration, relative extent, and uniformity of drug absorption compared to those observed after administration of the control aqueous suspension. The potentiating effects of the lipid on drug absorption persisted on multiple dosing but at a somewhat reduced level.