Bioequivalence studies of five brands of ampicillin trihydrate capsules.

Using the microbiological assay method, the bioavailability of ampicillin in healthy human volunteers has been examined. The plasma levels were used to determine the extent and rate of bioavailability following oral administration of 250 mg capsules produced by 5 different manufacturers. Balanced incomplete block design was employed and standard statistical techniques were used to detect any significant difference between multivariate and univariate characteristics. The results indicate that the different brands are almost bioequivalent with respect to the rate of bioavailability but that they are bioinequivalent with respect to the extent of bioavailability.