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.

Abstract: Particle for use especially as a fat substitute, characterized in that it includes an insoluble hydrophile matrix, surrounded by a hydrophobic layer of fatty acids bound to the matrix by covalent bonds and capable of interacting with lipidic or amphiphilic compounds. The invention also concerns a composition for use as a fat substitute and a process for the preparation of such particles.