Biodegradable particulate vector for transporting molecules having

Abstract

A biodegradable particulate vector for transporting biologically active molecules is prepared containing a nucleus formed of a cross-linked polysaccharide or oligosaccharide matrix having grafted ionic ligands, a layer of fatty acid compounds covalently bonded to the nucleus and a layer of phospholipids hydrophobically bonded to the layer of fatty acid compounds. Dextran, cellulose or starch may be cross-linked with epichlorohydrin to form a cross-linked polysaccharide matrix. Ionic ligands may be grafted using an acidic compound such as succinic acid, phosphoric acid or phosphorous oxychloride, or a basic compound such as choline, hydroxycholine, 2-(dimethylamino)ethanol or 2-(dimethylamino) ethylamine fastened onto the grafted acidic compound. Phosphoric acid or phosphorous oxychloride in one step provide both cross-linking and ionic ligands. Co-cross-linking can be obtained using a protein such as keratin, collagen or elastase. The vector may be prepared by reacting succinic acid monochloride with a cross-linked polysaccharide matrix to graft succinic acid onto the matrix to form the nucleus having ionic ligands, grinding the nucleus to a size between 10 .mu.nm and 10 .mu.m, drying, coupling fatty acid compounds to the nucleus and hydrophobically bonding phospholipids to the fatty acid compounds. After coupling the fatty acid compounds and before bonding the phospholipids, a molecule having biological activity may be added. The succinic acid monochloride is preferably prepared by reacting succinic acid dichloride with free succinic acid to form pure crystalline succinic acid monochloride.