Relative hypoglycemia of rectal insulin suppositories containing deoxycholic acid, sodium taurocholate, polycarbophil, and their combinations in diabetic rabbits

Abstract

In this study, insulin suppositories containing 50 U insulin incorporated with 50 mg of deoxycholic acid, sodium taurocholate, or both were placed in the rectum of alloxan-induced hyperglycemic rabbits. A large decrease in plasma glucose concentrations was observed, and the relative hypoglycemias were calculated to be 38.0%, 34.9%, and 44.4%, respectively, compared with insulin subcutaneous (s.c.) injection (40 U). Insulin suppositories containing 50 mg polycarbophil alone or mixed with 50 mg deoxycholic acid produced relative hypoglycemia of 43.1% and 42.2%, respectively. The most pronounced effect was observed with the addition of polycarbophil to the suppository formulation containing a combination of deoxycholic acid and sodium taurocholate, which produced a 56% relative hypoglycemia compared with subcutaneous injection. These suppository formulations could be very promising alternatives to the current insulin injections, being roughly half as efficacious as subcutaneous injection.