Abstract
The bioavailability of oxolinic acid (OA) in three different preparations (A; suspension, B and C; commercial powders) with different mean particle sizes of OA (A; 1μm, B; 5μm, C; 20μm) was studied after oral administration to chickens (20 mg/kg). Effect of administration conditions, fasting and non-fasting, was also studied. The dissolution rates of the preparations showed large differences according to differences in mean particle size. Under fasting conditions, significant differences in extents of bioavailability were found among the preparations, although the bioavailabilities of preparations A and B were almost the same. The bioavailabilities of OA from preparations B and C were enhanced after oral administration, and the differences in bioavailability between the preparations became also greater under non-fasting conditions. From the results, it is suggested that the bioavailability of OA of which mean particle size is more than 5μm depends on the dissolution rate, but not of which less than 5μm.
