Bioavailability of propranolol and bendrofluazide formulations.

In this comparative bioavailability study in 12 healthy volunteers the blood level profiles of both propranolol and bendrofluazide were studied following the multiple oral administration of the drugs as a fixed combination (Inderetic) and as a free combination at doses of 80 mg propranolol twice daily and 2.5 mg bendrofluazide twice daily. There were no statistically significant differences between the two regimens in terms of individual propranolol blood levels, half-lives and areas under the curve. The half-lives were between 5 and 8 h. Thus the bioavailability of propranolol from the fixed combination is equivalent to that from the free combination. The mean peak bendrofluazide blood levels were slightly higher following the administration of the fixed combination. This difference was statistically significant only at 1 and 2 h after the first dose. There were no statistically significant differences between these two bendrofluazide regimens in terms of half-life and area under the curve. Thus the bioavailability of bendrofluazide from the fixed combination is equivalent to that from the free combination. It is concluded therefore that by combining bendrofluazide and propranolol in a fixed capsule formulation does not affect significantly the systemic bioavailability of either component.