ABSORPTION OF INSULIN USING WATER-IN-OIL-IN-WATER EMULSION FROM AN ENTERAL LOOP IN RATS

The present work was undertaken to prepare water-in-oil-in-water (W/O/ W) emulsions as a carrier for insulin via the enteral route, The emuls ions were prepared by a two-step procedure using a homogenizer. To avo id insulin escape from the inner aqueous phase, 3, 5 or 10% gelatin wa s added in the inner phase. The oily phase was composed of 5% lecithin , 20% Span 80 and 75% soybean oil, The purified water containing 3% Tw een 80, was used for the enter aqueous phase. in addition, these Emuls ions were filtered with a membrane filter (0.45 mu m) to obtain smalle r emulsion particles. The stability of the emulsions Has evaluated by a turbidity measurement method and photomicrographic observation, BS' the addition of gelatin to the inner aqueous phase and storage at 4 de grees C, the stability of the emulsions could he improved. The hypogly cemic effects of insulin after administration of emulsion to the stoma ch, the duodenum, the jejunum, the ileum and the colon were examined u sing an in situ loop method in rats. A significant hypoglycemic effect was observed at the ileum and colon loops after administration of the filtered emulsions containing 5% gelatin in the inner phase. These fi ndings suggest that the W/O/W multiple emulsions stabilized by gelatin can improve ileal and colonic absorption of insulin.