A steady-state evaluation of the bioavailability of chronotherapeutic oral drug absorption system verapamil PM after nighttime dosing versus immediate-acting verapamil dosed every eight hours.

To compare the steady state pharmacokinetics of the 200 mg verapamil PM CODAS (chronotherapeutic oral drug absorption system) formulation dosed nightly versus immediate-acting verapamil 80 mg tablets dosed three times daily, an open-label, single-dose, two-treatment, two-period, two-sequence, balanced, randomized crossover study was performed with a 7-day washout between two treatment periods. Twenty-four healthy male subjects completed the study. All subjects received CODAS verapamil PM 200 mg under fasting conditions dosed at nighttime or verapamil 80 mg dosed three times daily at 8-hour intervals in a randomized fashion. CODAS verapamil PM 200 mg dosed at night for 5 days results in a plasma profile with a lag time of approximately 4 hours suitable for nighttime dosing. Significantly lower plasma concentrations of both enantiomers of verapamil and norverapamil resulted in lower peak-to-trough fluctuations and should ensure the safety of the product. Both medications tested in this study were well tolerated by the group of healthy volunteers.