Effects of Atropine and Loperamide on the Agitating Force and GI Transit Time in Dogs in Drug Absorption Studies

Abstract

There are difficulties in drug absorption studies using dogs because of different gastrointestinal (GI) conditions between these animals and humans, including shorter intestinal transit time and strong agitation force in the GI tract. We attempted to modify the agitation force and GI transit time using atropine and loperamide. The agitation force was examined based on in vitro/in vivo correlation for two controlled release (CR) formulations of acetaminophen. Atropine treatment considerably reduced the agitating force whereas that of loperamide did not.