Ph-selective delivery system using crosslinked polymeric resins as vehicles

Abstract

This invention provides a method of preparing a polymeric delivery system for active ingredients having enhanced site specific release performance characteristics. The delivery system is formed either by attaching the active ingredient to a linker through an acid-sensitive covalent bond, then forming a covalent bond between the linker and a portion of the subunits of a crosslinked polystyrene polymer, or by attaching a linker to a portion of the subunits of a crosslinked polystyrene polymer, then attaching the active ingredient to the polymer-linker combination through an acid-sensitive covalent bond. The invention also provides a delivery system comprising an active ingredient covalently bonded through an acid-sensitive covalent bond to a linker, which is in turn covalently bonded to a portion of subunits of a crosslinked polystyrene polymer. The invention further provides a method for treatment or prevention of gastric ulcers using a delivery system capable of delivering prostaglandin or prostacyclin drugs, especially misoprostol.

Dependencies are inferred from the claim text.