ABSORPTION-PROMOTING ADJUVANTS - ENHANCING ACTION ON RECTAL ABSORPTION

Studies of absorption-promoting adjuvants used for the modification of the barrier function of the rectal membrane are interesting for bioch emical research as well as providing a basis for the development of ne w formulations of poorly absorbed drugs such as some moderately large water soluble drugs and peptides. Compounds such as chelating agents a nd sulfhydryl depleters increase the rectal absorption of drugs throug h the paracellular route and transcellular route, respectively, by mod ifying the barrier function of each route. Salicylate, its derivatives and fatty acids also increase rectal drug absorption through both rou tes. Lectin increases rectal absorption of drugs by inducing microvill ous infusion. With respect to formulation development, ampicillin supp ositories incorporating sodium caprylate as an absorption promoting ad juvant were confirmed clinically to be an effective formulation, acid are a marketed product in Japan. In human trials, administration of in sulin in a combination with salicylate inhibited postprandial hypergly cemia in diabetic patients. (C) 1997 Elsevier Science B.V.