Construction of Gelatin Microsphere / Magnesium Phosphate Bone Cement Composite Drug Sustained Delivery System

doi:10.15541/jim20160553

Abstract

Abstract:

Emulsification crosslinking method was applied to prepare drug-loaded gelatin microspheres, of which the particle size was mainly between 100-300 μm. The influence of the crosslinking agent content, drug content and rotation speed on the drug-loading rate and encapsulation efficiency and the influence of the drug content and rotation speed on the microspheres’ diameter were analyzed. The drug-loaded gelatin microspheres were deliberately combined with magnesium phosphate cement to produce porous magnesium phosphate composite bone cement with drug slow-release property, and then the changes of porosity of the composite system in the process of microsphere degradation and the drug release characteristics of the composite system in vitro were both explored. Results show that with the increase of glucose concentration, both the drug-loading rate and encapsulation efficiency increase firstly and then decrease, while both the drug content and the drug-loading rate increase and the encapsulation efficiency increases firstly and then decreases. Both the drug-loading rate and encapsulation efficiency decrease with the increase of rotation speed. Comprehensive analysis show that the gelatin microspheres with high drug-loading rate and suitable diameter can be obtained under the condition of rotation speed of 400 r/min, glucose concentration of 0.5 g/mL and the mass ratio of drug to gelatin of 1:2. The drug release characteristics in vitro were studied by immersing the magnesium phosphate cement, which was combined with different proportions of drug-loaded microspheres, into the Tris-HCl buffer solution. Results show that in the early releasing stage of 1-10 h, the drug release rate is rapid and then it obviously slows down. After being released for 7 d, microspheres almost degraded completely and the drug release ratio reaches 60%-89%. Drug slow-release property is achieved to some extent.

Key words: gelatin microspheres, drug loading, magnesium phosphate based bone cement, drug sustained delivery

CLC Number:

TB321
R318

YU Su-Chun, YU Ying, DAI Hong-Lian. Construction of Gelatin Microsphere / Magnesium Phosphate Bone Cement Composite Drug Sustained Delivery System[J]. Journal of Inorganic Materials, 2017, 32(6): 655-660.

Figures/Tables 10

Fig. 1 Effects of glucose content on drug-loading rate and entrapment efficiency for microsphere

Fig. 2 Effects of drug content on drug-loading rate and entrapment efficiency for microsphere

Fig. 3 Effects of drug content on microspheres’ diameter

Fig. 4 Effects of rotation speed on drug-loading rate and entrapment efficiency

Fig. 5 Effects of rotation speed on microspheres’ diameter

Fig. 6 SEM image of MPBC bone cements hardened for 24 h

Fig. 7 Effect of drug-loaded gelatin microspheres on bone cement degradation rate

Fig. 8 Effect of drug-loaded gelatin microspheres on bone cement porosity

Fig. 9 Cross-sectional SEM images of MPBC-8 bone cements on the 1 d (a) and 7 d (b) of degradation

Fig. 10 Drug release profile of the complex magnesium phosphate bone cement

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