Bioequivalence of two pharmaceutical forms of diltiazem

Diltiazem, a calcium-channel blocking agent, has been shown to be a potent coronary vasodilator used in the treatment of ischaemic heart disease. The present study was conducted to compare the bioavailability of regular 60 mg tablets administered every 6 h with sustained release capsules of 120 mg administered every 12 h. High-performance liquid chromatographic analysis was carried out for determination of diltiazem and one of its metabolites desacetyldiltiazem in six male patients. The relative bioavailability of this sustained-release pharmaceutical form did not show any significant difference with that of tablets.