BIODEGRADABLE MICROSPHERES - A NEW DELIVERY SYSTEM FOR GROWTH-HORMONE

A drug delivery system for biologically active agents targeted to spec ific cells could be used to improve tissue repair in orthopaedics. The system should be controllable and capable of drug release over an ext ended period of time. Biodegradable, membrane-moderated, monolithic mi crospheres for the controlled release of growth hormone (GH) were deve loped and the release of GH was monitored in vitro. Cross-linked gelat in microspheres were used as the vehicle, with the drug dispersed with in the gelatin. The amount of GH released from the microspheres was in creased following ultrasonication. The release of growth hormone was m onitored in phosphate buffered saline and horse serum. Interestingly, a higher level of GH was detected in the phosphate buffered saline tha n in serum. In addition, both pH and enzyme-induced degradation had an effect on the swelling kinetics of the gelatin microspheres. The rele ase of GH from the microspheres was diffusion controlled, during the t ime period studied.