Steady-state bioavailability of controlled-release oxycodone in normal subjects

The steady-state bioavailability of a controlled-release (CR) oxycodone tablet was compared with that of an immediate-release (IR) oxycodone solution in a randomized, analytically masked, multiple-dose, crossover study in 24 normal subjects. Each subject received either one 10-mg CR oxycodone tablet every 12 hours for 4 days or 5 mL of a 1-mg/1 mL IR oxycodone solution every 6 hours for 4 days. Steady state was achieved after approximately 1 day of dosing. The mean (+/- SD) maximum plasma oxycodone concentrations for CR oxycodone and IR oxycodone were 15.1 +/- 4.7 ng/mL and 15.6 +/- 4.4 ng/mL, respectively. The time to maximum concentration (Tmax) was approximately twice as long for CR oxycodone (3.2 +/- 2.2 hours) as for IR oxycodone (1.4 +/- 0.7 hours) (P = 0.005). The area under the plasma concentration-time curve from 0 to 12 hours at steady state was 103.6 +/- 40.0 ng.h/mL for CR oxycodone and 99.0 +/- 35.8 ng.h/mL for IR oxycodone. Except for Tmax, there were no significant differences in pharmacokinetic parameters between treatments. Approximately twice as many adverse experiences, several of longer duration than noted with CR oxycodone, were reported with IR oxycodone. The bioavailability of the CR tablet was equal to that of the IR solution; however, the rate of oxycodone absorption from the CR tablet was slower than that from the IR solution, as shown by the Tmax value. The use of CR oxycodone will allow selection of the most clinically appropriate nonopioid analgesic, as well as independent titration and dosing, thereby enhancing therapeutic flexibility.