The invention relates to biopolymer-gel based depot systems for prolonged and/or controlled release delivery of biologically active agents, methods for the manufacture of the biopolymer based gel-depots which include a biologically active agent, and uses of such biopolymer gel-depots in therapy. The biopolymer-gel based depot systems comprise a biocompatible polyaminosaccharide and/or protein a biocompatible phosphate and/or sulphonamide compound a biologically active agent an aqueous insoluble alkaline earth metal phosphate and a biocompatible glycan and/or proteoglycan.
