Biodegradable PLGA Microspheres for Controlled Delivery of Parathyroid Hormone Related Peptide

PLGA microspheres were chosen as the carrier to overcome the limitations of application for parathyroid hormone related peptide (PTHrP) which can increase the number and viability of osteoblasts and promote bone formation with a low-dose, long time, intermittent administration. PLGA microspheres were prepared by a water-in-oil-in-water (W1/O/W2) double emulsion solvent evaporation and PTHrP1-34 was encapsulated to the microspheres by a technique with good sphericity and high efficiency. The micrographs of polyester microspheres were evaluated by scanning electron microscope (SEM). The polyester microspheres had a good spherical shape. PTHrP1-34 loaded microspheres exhibited a slow release behavior for about 25 days, which was accord with expection. The effect of PTHrP1-34 loaded microspheres on pre-osteoblastic proliferation was studied via cell proliferation evaluation experiments. The results demonstrated that PTHrP1-34 loaded PLGA microspheres can enhance the proliferation and differentiation of MC3T3 cell effectively. Alkaline phosphatase (ALP) quantification experiment was also performed to investigate the influence of differentiation. The cells incubated with PTHrP1-34 loaded PLGA microspheres exhibited higher ALP level which was related to the differentiation. In summary,PTHrP1-34 loaded PLGA microspheres show great potential as a promising delivering and releasing carriers for application of oral implantology.