The Objective and Timing of Drug Disposition Studies, Appendix V. A Comparison of the Bioavailability of Three Dosage Forms of Terfenadine

Antagonistic effect against histamine-induced wheals was used to evaluate the bioavailability of terfenadine in monkeys. A rapidly dissolving tablet formulation of terfenadine shows essentially identical bioavailability to a liquid suspesion. A less readily dissolving capsule formulation lags considerably in time with regard to availability, and some question remains as to whether the total quantity in the capsule is available.