Relative bioavailability of aspirin gum.

The bioavailability of aspirin gum relative to unbuffered aspirin tablets was determined in six normal volunteers. Twenty-four hours following the administration of two aspirin tablets, 91.2 +/- 1.7% (SE) of the 648-mg dose was recovered in the urine. The relative bioavailability of aspirin gum was 69.5 +/- 3.4% (SE), based on cumulative 4-hr urinary excretion of total salicylate after the chewing of three gum tablets for 15 min. The chewed gum was analyzed for total salicylate and contained an average of 37.8% of the administered dose. When added to the cumulative amount of total salicylate excreted in the urine at 24 hr after dosing, the salicylate contained in the chewed gum accounted for essentially 100% of the dose administered. Chewing aspirin gum for up to 30 min did not significantly (p greater than 0.05) reduce the amount of salicylate entrapped in the gum base when compared to chewing times of 5, 10, and 15 min. Based on the results of this study, four pieces of aspirin gum would be needed to provide the same amount of salicylate to the general circulation as two 324-mg aspirin tablets.