Influence of food and fluid ingestion on aspirin bioavailability.

The influence of test meals and accompanying fluid volume on aspirin bioavailability from commercial tablets was determined following single oral doses to healthy male volunteers. Plasma aspirin and salicylate levels were determined simultaneously using a GLC end-point. Area analysis indicated that approximately 5--8% of absorbed drug entered the systemic circulation as unchanged aspirin in nonfasted subjects compared to 16--18% in fasted individuals. Food tended to reduce the appearance rate of aspirin into the circulation, resulting in lower and somewhat more sustained levels than with fasting. Plasma salicylate levels were not influenced markedly by the various treatments, although levels were higher in fasted than in nonfasted subjects during the 1st hr after dosing. After this time, fat pretreatment tended to produce higher levels than other treatments.