The Influence of Dosage Form on Papaverine Bioavailability

Abstract

The bioavailability of sustained-release papaverine HCl dosage forms were compared to equivalent doses of the drug administered as an elixir and conventional compressed tablets to 12 healthy human subjects. Papaverine plasma levels were determined using a gas-chromatographic procedure. The drug was absorbed more rapidly and completely from the 2 nonsustained-release formulations. There was a large intersubject variability, and the plasma half-life of the drug was estimated to be 1 h. The area under the plasma level-time curve for the 9 sustained-release products ranged from 18-64% relative to the area achieved by the papaverine elixir. Apparently, the sustained-release dosage forms of papaverine included in each study group could be considered bioequivalent, but they exhibited inadequate bioavailability relative to the elixir or the compressed tablet dosage form.