Study on preparation and in vitro release of gelatin microspheres loaded with steroidal saponins from Ophiopogon japonicus

The purpose of this study is to develop microspheres (core/shell) based on natural polymers used for bone tissue engineering. The morphology, structure, particle size, drug loading and encapsulation efficiency of the microspheres were characterized by field emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FTIR), ultraviolet spectrophotometer (UV) and laser particle size analyzer. The results showed that the gelatin (shell) microspheres loaded with steroidal saponins (core) prepared under the best process conditions were smooth and round, the particle size was about 4 μm. The drug loading and encapsulation efficiency were 24.7% and 97.5%, respectively. In the process of in vitro simulated release, the microspheres conformed to the first-order equation release kinetic model, and cumulative drug release in 8 days reached 85.6%. This may suggest the potential use of microspheres for treatment of bone tissue engineering over long periods.