In vitro adsorption of diphenoxylate hydrochloride on activated charcoal and its relationship to pharmacological effects of drug in vivo. I.
The adsorption of diphenoxylate hydrochloride, a potent antidiarrheal agent, on activated charcoal powder was studied in vitro. Langmuir adsorption isotherms were established at pH 4 and 7, and the maximum adsorption capacity of charcoal for this drug was estimated using these values. Activated charcoal modified the bioavailability of diphenoxylate hydrochloride in vivo. The antipropulsive action of diphenoxylate in the mouse was strongly inhibited in the presence of activated charcoal. A comparative evaluation of charcoal and chromium oxide used as inert, nonabsorbable markers revealed that chromium oxide may be the marker of choic in GI transit studies in laboratory animals since it does not influence the bioavailability of diphenoxylate hydrochloride.
D000327:Adsorption; D000818:Animals; D001682:Biological Availability; D002606:Charcoal / Q000494:pharmacology; D002857:Chromium / Q000494:pharmacology; D004157:Diphenoxylate / Q000378:metabolism / Q000494:pharmacology; D005769:Gastrointestinal Motility / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D007540:Isonipecotic Acids; D008297:Male; D051379:Mice; D010087:Oxides / Q000494:pharmacology
D007540:Isonipecotic Acids; D010087:Oxides; D002857:Chromium; D002606:Charcoal; D004157:Diphenoxylate