Controlled-release formulations of propranolol and verapamil

The in vitro and clinical behavior of new controlled-release formulations of propranolol and verapamil are reviewed. In vitro dissolution studies have proved to be of little value in determining the clinical activity of these new dosage forms. There is a difference between the blood levels found with the new formulations and those of the reference products. The once-daily verapamil product was evaluated in black hypertensive patients with promising results and suggests that this dosage form of verapamil may be successful as monotherapy for treating this patient population.