Example: Theophylline liquid preparation was used as a standard for the evaluation of two new oral theophylline tablets. The AUC after administration of 400 mg of the liquid preparation was 100 mg-hr/L. If the AUC after administration of 400 mg of product 1 was 86 mg-hr/L and the AUC after administration of 200 mg of product 2 was 38 mg-hr/L, calculate the bioavailability of the two new products relative to the standard formulation
The relative bioavailability can be determined from the AUC(test)/AUC(standard) ratio after administration of similar doses. When the doses are different, the AUCs have to be adjusted to represent equal doses before determining the ratio.
