Abstract
The effect of food on the gastrointestinal absorption of amobarbital was studied in the rats. The presence of food in the gastrointestinal tract decreased significantly the serum level and brain level of amobarbital and reduced the sleeping time induced by the drug. The amounts of amobarbital remaining to be absorbed in the stomach and intestines were determined in fasted and nonfasted rats. Most of the drug unabsorbed was contained in the stomach in both experimental conditions, but the amounts unabsorbed were greater in the nonfasted rats. It was clarified by the in situ experiment that the primary absorption site of amobarbital was the small intestine. Thereafter, it was demonstrated that the presence of food in the gut decreased the pharmacological activity of amobarbital by the decrease of absorption rate based on delayed gastric emptying. Since amobarbital is very rapidly absorbed in the small intestine, the presence of food will not decrease the extent of absorption of the drug.
