Effect of the Lactide/Glycolide Ratio and Molecular Weight of PLGA on the Bovine BMPs Microspheres Systems

Abstract

The present investigation was aimed at optimization of BMPs loaded PLGA microspheres formulations resulting in improved encapsulation efficiency and sustained release of BMPs by varying the molecular weight and copolymer composition of PLGA. Double-emulsion solvent evaporation method was used to prepare the microspheres. The effect of polymer molecular weight and copolymer composition on particle properties and release behavior in vitro was reported. The particle size and encapsulation efficiency increased with increase in molecular weight and lactide content of PLGA. While BMPs release in vitro decreased with increase in molecular weight and lactide content of PLGA. SEM pictures revealed that almost all microspheres were spherical but internal morphology was different. The morphology of PLGA microspheres with exorbitant molecular weight(100kD) was anomalistic whereas the morphology of PLGA microspheres with higher glycolide content(50) have porous structures.

Strategies to Control or Mimic Growth Factor Activity for Bone, Cartilage, and Osteochondral Tissue Engineering

“…For example, increasing cross-linking density and decreasing degradation rate and particle size have been shown to decrease the amount of GF released over time . Synthetic copolymers of poly­(lactic- co -glycolic acid) (PLGA) have been widely used for GF delivery due to their tunable physicochemical properties and well-known degradation patterns. − GF retention time in PLGA microparticles has been controlled by tuning molecular weight, − lactic to glycolic acid ratio, end-group functionalization, and GF concentration . For example, BMP-2 release from low-molecular-weight PLGA microparticles was significantly faster than release from high-molecular-weight PLGA microparticles…”