Preparation and characterization of PLGA microspheres by the electrospraying method for delivering simvastatin for bone regeneration

Microparticles formulated from poly (D,L-lactic-co-glycolide) (PLGA), a biodegradable polymer, have been investigated extensively as a drug delivery system. In this study, solid tiny PLGA microspheres were fabricated using the electrospraying method. PLGA polymer was dissolved in dichloromethane (DCM), and the solution was electrosprayed. The electrospraying conditions were adjusted so that the stream ejected from the needle was divided into spheres instead of continuous fibers or irregular-shaped particles. Several experiments were carried out using the PLGA-DCM source solution with different amounts of simvastatin (SIM), a drug that enhances bone regeneration, to understand this drug delivery system. The surface morphology and microstructure of the microspheres formed were characterized by scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and differential scanning calorimetry. The in vitro experiments on drug loading and drug release behavior of the microspheres suggested a drug encapsulation efficacy >90%. The drug was continuously released from the microspheres for >3 weeks. Other experiments, such as MTT, cell attachment and proliferation and reverse transcription-polymerase chain reaction showed good biocompatibility of the electrosprayed PLGA microspheres, which increased in the presence of SIM. Thus, electrosprayed PLGA microspheres have potential as a drug delivery system and application in bone tissue engineering.