Biodegradable polymeric drug delivery system with adjuvant activity

An antigen delivery system utilizing a biodegradable polymer with good mechanical properties in combination with a material stimulating the immune system. The material having adjuvant activity may be polymer degradation products or an adjuvant which is contained within or bound to the polymer. In one embodiment, the polymer is formed from tyrosine dipeptides. Poly(CTTH-iminocarbonate) is a preferred tyrosine dipeptide polymer for constructing implantable delivery systems for antigenic material. The polymer is not an adjuvant in itself but degrades into products which stimulate the immune system. The tyrosine dipeptide can also be used as a conventional adjuvant. The advantages of the system are that a polymer can be used to form a biodegradable integral structure which is useful as both an implantable source of an antigen or other biologically active compound and as a control means for the rate of release of the biologically active compound, wherein the result is sustained, relatively constant delivery of antigen with simultaneous stimulation of the immune response.