Effects of Food on Oxaprozin Bioavailability

: Twelve healthy volunteers received single 1200‐mg oral doses of oxaprozin while fasting and immediately after a standard breakfast in a two‐period crossover design with three weeks between administrations. Oxaprozin plasma concentrations were monitored during a 10‐day period after each dose. No statistically significant differences were noted between kinetic parameters obtained in the fasting and postprandial states for mean peak plasma concentrations (Cmax, 103 vs, 109 μg/mI), absorption rate constants (ka, 1.1 vs. 0.8 h−1), or total AUC (7042 vs. 7066 μg/ml · hr). Compared with doses administered during fasting, postprandial doses led to a delay in the onset of absorption in the gastrointestinal tract (lag time t0, 24 vs. 9 min), but not in the peak time (tmax ∼5 hours). Oxaprozin's mean residence time t̄ was slightly shorter for subjects in the postprandial state (72 hours) than for those in fasting state (73 hours), probably because of the intrasubject variability in half‐life (48 vs. 50 hours). The results of this study indicate that the ingestion of food has no effect on the bioavailability of oxaprozin.