エマルションの最前線 エマルションによるドラッグデリバリー

Abstract

A new solid-in-oil-in-water (S/O/W) emulsion consisting of edible surfactants, an edible oil, and a water-soluble drug has been developed for oral administration of peptide/protein drugs. Insulin, which is a hydrophilic macromoleclule, was converted into a lipophilic complex using edible surfactants. As the resultant complex can be directly solubilized in the oil phase, surfactant-insulin complexes can be incorporated into the oil phase of oil-in-water emulsions, allowing the formulation of stable S/O/W emulsions. The capability of S/O/W emulsions in the control of blood glucose was investigated with diabetic model rats. The glucose level in the serum slowly decreased over several hours when the S/O/W emulsions were orally administered, while the aqueous solution of insulin (as the control) showed no significant effect on the blood glucose level. The hypoglycemic effect of surfactant-insulin complex incorporated into the S/O/W emulsions and the stable encapsulation of insulin into dry emulsion formulations will offer one way to oral delivery of biopharmaceuticals.