Bioavailability of propranolol and bendrofluazide formulations

Area of Science:

• Pharmacokinetics
• Clinical Pharmacology
• Drug Formulation

Background:

• Propranolol and bendrofluazide are commonly prescribed medications, often used in combination for managing hypertension.
• Fixed-dose combination formulations aim to improve patient compliance and therapeutic outcomes.
• Assessing the bioavailability of each component in a fixed-dose combination is crucial for ensuring therapeutic equivalence.

Purpose of the Study:

• To compare the bioavailability of propranolol and bendrofluazide when administered as a fixed combination (Inderetic) versus a free combination.
• To determine if the fixed formulation significantly alters the systemic absorption of either drug.

Main Methods:

• A comparative bioavailability study involving 12 healthy volunteers.
• Multiple oral administration of propranolol (80 mg BID) and bendrofluazide (2.5 mg BID) in both fixed and free combination forms.
• Analysis of blood level profiles, including peak concentrations, half-lives, and areas under the curve (AUC).

Main Results:

• No statistically significant differences were observed in propranolol blood levels, half-lives, or AUC between the fixed and free combinations.
• Mean peak bendrofluazide blood levels were slightly, but not significantly, higher in the initial hours after the first dose with the fixed combination.
• Bendrofluazide's half-life and AUC were equivalent between the two formulations, indicating comparable overall bioavailability.

Conclusions:

• The fixed capsule formulation of propranolol and bendrofluazide does not significantly affect the systemic bioavailability of either component.
• The bioavailability of propranolol from the fixed combination is equivalent to that from the free combination.
• The bioavailability of bendrofluazide from the fixed combination is equivalent to that from the free combination.