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Objective:To prepare polyvinyl alcohol (PVA) and hydroxyapatite (HA) composite embolization microspheres and investigate their physicochemical properties.Methods:PVA/HA composite embolization microspheres were prepared by reverse suspension polymerization, using PVA and HA as dispersed phases, liquid paraffin containing sorbitan fatty acid ester as the continuous phase, and glutaraldehyde as the cross-linking agent. The morphology, particle size distribution, and microscopic morphology of PVA/HA composite embolization microspheres were observed by optical microscopy and scanning electron microscopy. The chemical structure of PVA/HA composite embolization microspheres and the elasticity, drug loading, and drug release properties of PVA/HA composite bolus microspheres were characterized by Fourier infrared spectroscopy.Results:The PVA/HA composite embolization microspheres were internal, porous round spheres with a particle size distribution of 50-300 μm. The elastic properties of PVA/HA composite embolization microspheres were(13.6±0.145) kPa, which was 2.28 times that of PVA microspheres, and the drug loading capacity and encapsulation efficiency were (76.80±1.22) mg/g and (38.4±12.7)%, respectively. The maximum cumulative release rate of the microspheres within 7 days was (7.37±0.101)%, and the maximum cumulative release was (256.2±9.8) μg.Conclusions:PVA/HA composite embolization microspheres have good mechanical properties and drug-loading and drug-releasing properties, which provide an important reference for their use as medical devices.
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Objective To evaluate the sterilizing efficiency ofabscrbable poly-L-lactide (PLLA) screws sterilized with ethylene oxide and 60Co-γ radial. Methods One group of PLLA screws was sterilized in the ethylene oxide sterilization ease. In order to eliminate the rudimental ethylene oxide, the sterilized screws was put in the air for five days. The other group of PLLA screws was sterilized with 60Co-γ radial with absorbable dose of 15 kGy. Then all sterilized screws were characterized. Results Compared with the primal bend intensity of the PLLA screws, the bend intensity of sterilized screws did not descend remarkably (P＞0.05). Compared with the primal molecular weight of the PLLA screws, the molecular weight of screws with 60Co-γ radiation sterilization re-markably decreased 11%. It indicated that the material had degraded. The molecular weight of screws with ethylene oxide sterilization ordy decreased 3%. It indicated that the material didn't degrade obviously. Conclusion Ethylene oxide sterilization is a better way for sterilizing absorbable PLLA screws.