AN EVALUATION OF THE EFFECT OF FOOD ON THE ORAL BIOAVAILABILITY OF SUSTAINED-RELEASE MORPHINE-SULFATE TABLETS (ORAMORPH SR) AFTER MULTIPLE DOSES

The effect of food on the oral bioavailability of sustained-release morphine sulfate tablets (ORAMORPH SR; Roxane Laboratories, Inc., Columbus, OH; OSR) was examined in an open-label, randomized, two-period crossover study. Healthy male volunteers received a 30-mg OSR tablet orally every 12 hours for seven doses during both the fasted and fed states. Dosing periods were separated by a 14-day washout. Volunteers in the fasted group received all doses either 2 hours before or after meals. Volunteers in the fed group received all doses immediately after meals. All meals were standardized. Serial blood samples were collected for analysis of plasma morphine concentration by radioimmunoassay. Pharmacokinetic parameters were calculated using plasma concentration data collected after the last dose at 72 hours of each dosing period. The two one-sided t analysis indicated confidence intervals between 80% and 120% for maximum peak plasma concentration (Cmax), AUC72-84hr, Cavg, and Cmin. The relative bioavailability of OSR administered after meals was 90.2% of that administered in the fasted state. As compared with the fasted condition, morphine bioavailability was essentially unchanged when multiple oral doses of 30-mg OSR tablets were given after meals.