Biodegradable microparticles with immobilized peptide for wound healing

Thrombin receptor agonist peptide (TRAP-6) may be successfully used instead of thrombin to stimulate regeneration of damaged tissues. Thrombin application is limited by its high price, instability, and proin-flammatory effect at high concentrations. Immobilization of TRAP-6 into a matrix based on lactic and glycolic acid copolymer (PLGA) prevents its destruction by peptidases located in the wound and can also provide controlled release of the peptide. PLGA microparticles with the immobilized peptide were prepared by the double emulgation method. The presence of the immobilized peptide increased the porosity of the microparticle surface detected by scanning electron microscopy. Kinetics of the TRAP-6 release was characterized by a dramatic increase in its concentration in buffer solution (pH 7.5) during the first 2 h after the experiment beginning, and the complete release of the peptide after 20 h. An investigation of TRAP-6 destruction by scanning electron microscopy revealed the increase in the microparticle size and surface porosity already after one day of incubation, and the destroyed microparticles were aggregated by the seventh day of the incubation. Thus, peptide immobilization into PLGA microparticles may be employed for elaboration of a prolonged action preparation with the controlled release of the active agent (peptide).