Biodegradable particulate vector for transporting molecules having

Abstract

A biodegradable particulate vector for transporting biologically active molecules is prepared containing a nucleus for containing a biologically active molecule, a first layer of fatty acid compounds covalently bonded to the nucleus and a second layer of phospholipids hydrophobically bonded to the first layer. The nucleus is between 10 nm and 10 .mu.m in size and is formed of a cross-linked polysaccharide or oligosaccharide matrix onto which ionic ligands are uniformly grafted. The cross-linked polysaccharide may be dextran, cellulose or starch cross-linked with epichlorohydrin. The ligand may be an acidic compound selected from succinic acid, phosphoric acid, citric acid, glycine, alanine, glutamic acid and aspartic acid, or a basic compound such as choline, hydroxycholine, 2-(dimethylamino)ethanol or 2-(dimethylamino)ethylamine fastened onto the matrix via the acidic compound. The polysaccharide or oligosaccharide may be co-cross-linked with a protein such as keratin/collagen or elastase. The vector may be prepared by reacting succinic acid monochloride in aqueous solution with a cross-linked polysaccharide or oligosaccharide matrix to graft succinic acid onto the matrix to form the nucleus, grinding the nucleus to a size between 10 nm and 10 .mu.m, drying the ground nucleus, coupling fatty acid compounds to the nucleus to form a first layer and hydrophobically bonding phospholipids to the first layer to form a second layer. The succinic acid monochloride is preferably prepared by reacting succinic acid dichloride with free succinic acid to form pure crystalline succinic acid monochloride.