Absorption and Excretion of Drugs. XXXIV. An Aspect of the Mechanism of Drug Absorption from the Intestinal Tract in Rats

Abstract

Some qualitative discrepancies from the pH-partition theory demonstrated with barbituric acid derivatives previously were examined with various types of drugs and the confirmation of the suggestion that the binding process to the mucosal surface is an important factor of the absorption from the small intestine was made. The absorption of the ionized form of drugs was also interpreted by this binding factor. Furthermore, the dispositions of the small intestine were compared with that of the other parts of the gastrointestinal tract. The effect of the N-methyl configuration on the absorption was also found to persist the importance of the binding process.