CHARACTERIZATION OF FLUIDS FROM THE STOMACH AND PROXIMAL JEJUNUM IN MEN AND WOMEN

Purpose. To chemically characterize the fluids available for drug diss olution in the upper gastrointestinal tract during the fasted state in humans, and to examine variations and potential gender differences re garding the physico-chemical properties of these fluids. Methods. Twen ty-four healthy volunteers, 12 females and 12 males, were intubated, a nd fluids from the stomach and upper jejunum were collected separately . Bulk pH, osmolality, electrolytes and total concentrations of bile a cids and proteins were assessed. To study intraindividual variations, eleven of the individuals were studied on more than one occasion. Resu lts. The stomach and upper jejunal fluids varied significantly in all the measured entities, except the total concentration of proteins. The intraindividual variability was pronounced in some of the individuals , both in the stomach and the upper jejunum. We did not, however, obse rve any gender differences. Conclusions. This study demonstrates the c omplex nature of the fluids available for drug dissolution in the stom ach and the upper small intestine in humans. The results can be used w hen designing a more physiological in vitro dissolution media represen tative for the fasted state. When designing such a medium, we suggest that gender differences not be taken into account.