Multiple Plasma Peaks of Acetaminophen and Ranitidine after Simultaneous Oral Administration to Rats

Acetaminophen (AAP) and ranitidine (RT) were coadministered orally to nine rats, and the possible contribution of the gastric emptying to the plasma concentration profiles of them was examined. The drugs showed multiple plasma peaks similar to the respective ones after separated administration of each durg. IT Implies that there is no significant interaction between AAP and RT in terms of the gastric emptying or drug absorption. There were no significant linear correlations of the peak patterns (peak height and peak time) between AAP andd RT. It is contrary to the expectation from the biphasic gastric emptying (BGE) theory previously suggested for AAP and RT. The BGE theory. Therefore, seemed to have some draw-backs in explaining satisfactorily the multiple plasma peaks of AAP and RT. Two more doubts raised previously against the BGE theory were also discussed.