Enhanced oral bioavailability of diltiazem by resveratrol in healthy human subjects: An open-label, two-period, sequential study

Background: The purpose of this study was to investigate the bioavailability enhancing potential of resveratrol (RSV) on diltiazem (DLT) treatment in healthy human volunteers. Materials and Methods: An open-label, two-period, sequential study was conducted in 12 healthy human male volunteers. A single dose of RSV 500 mg was administered daily for 10 days during the treatment phase. A single dose of DLT 30 mg was administered during the control phase and after treatment phases under fasting conditions. The blood samples were collected at predetermined time intervals after DLT dosing and analyzed using high-performance liquid chromatography. Results: Treatment with RSV significantly enhanced maximum plasma concentration, area under the curve, whereas the volume of distribution and apparent clearance (CL/F) of DLT was significantly decreased when compared to control. Conclusions: The results suggested that enhanced bioavailability of DLT might be attributed by bio enhancing the potential of RSV resulted by inhibition of P-gp and CYP3A4. Further, the dosage of DLT should be readjusted when it is used concomitantly with RSV supplements or food containing RSV.