POLYMERIC MATERIALS AS BIOMATERIALS UNDER PARTICULAR CONSIDERATION OFBIODEGRADABLE POLYMERS

Biomaterials may be defined as artificial materials which fulfill the mechanical requirements and interact with the biosystem they are in co ntact with in same way as a natural material would react in the same p lace. While the requirements of mechanical properties can be reached b y suitable organo-polymeric and inorganic materials the interfacial bi ocompatiblity is neither understood in all its complexity nor can be f ulfilled by any of the applied materials. Surface modification and cha racterization with greatest scrutiny and the observation of the answer of selected parameters of the biosystem are a subject of utmost inter est. A few examples will be presented. In the long range, however, it has to be considered that any material is degraded and hence should pr esent continuously a renewable biocompatible surface. On the other han d, materials are desired which deliberately are biodegradable. Present ly available materials are polylactides and copolymers. An alternative could be presented by polydepsipeptides because of two reasons, (i) t he local concentration of acid formed upon degradation would be reduce d as compared to polylactides which in certain cases might be advantag eous and (ii) the aminoacid units could carry side groups with bioacti ve molecules attached. Therefore, a new method of acylation of an amin oacid with a hydroxyacid is presented as well as the cyclisation to re sult in the cyclic depsipeptide and the polymerisation to yield the po lydepsipeptide. The microstructure of the polymers, the thermal proper ties and the degradation behaviour is presented.