Effect of Colchicine on Drug Absorption from the Rat Small Intestine in Situ and in Vitro

Abstract

The effect of colchicine (1 mg/kg i.p. on 2 successive days) on the absorption of isoniazid, quinidine and sufafurazole (sulfisoxazole) from the rat small intestine was studied in situ and in vitro. Colchicine produced 2 different types of histological damage in the small intestine, 1 with degenerative and the other with regenerative changes predominating. The small intestinal surface area was variably reduced. The colchicine-treated rats were lethargic and hypothermic as compared to controls. Colchicine retarded the disappearance of fluid and all 3 drugs from the small intestinal lumen in situ 2 days after the 1st colchicine injection. In vitro the total amounts of fluid and drugs passed through the intestinal wall were not significantly changed by colchicine, although there was a slight tendency towards an increased quinidine absorption. Colchicine as an antimitotic drug decreases drug absorption from the rat small intestine in situ, apparently due to the decreased surface area of the small intestine, the decreased water flux through the intestinal wall, the retarded intestinal motility and hypothermia of the rats. In vitro the changes are small, which makes the in vitro tests less suitable for studying the effect of colchicine on absorption.