Injectable PLGA microsphere/calcium phosphate cements: physical properties and degradation characteristics
Injectable PLGA microsphere/calcium phosphate cements: physical properties and degradation characteristics
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DOI：
10.1163/156856206778366004
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发表时间：
2006-01-01
影响因子：
3.6
通讯作者：
Jansen, J. A.
中科院分区：
文献类型：
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作者：
Habraken, W. J. E. M.;Wolke, J. G. C.;Jansen, J. A.
磷酸钙骨水泥(CAP)表现出良好的生物相容性，通常具有较高的机械强度，但总体上降解相对较慢。为了提高降解率，可以在水泥中引入大孔，例如通过在水泥中加入可生物降解的微球。本研究的目的是开发一种可注射的PLGA微球/帽水泥，具有足够的凝结/粘结性能和良好的机械和物理性能。采用水包油复乳法制备了PLGA微球。使用的帽水泥是Calcibon(注册商标)，这是一种商业上可获得的羟基磷灰石基水泥。制备了10：90和20：80干质量分数PLGA微球/帽圆柱形支架，并以微孔水泥为参照物。测定了注入性、凝结时间、粘结性能和孔隙率。此外，还在PBS(37摄氏度)中进行了为期12周的降解研究。结果表明，随着PLGA微球含量的增加，可注射性降低。PLGA/CAP样品的初凝时间和终凝时间均高于微孔样品。不同处方的微孔率分别为40.8%、60.2%和69.3%。降解研究表明，从第6周开始，10：90和20：80配方的周围介质有明显的质量损失和pH下降，表明PLGA受到侵蚀。PLGA微球/帽样品的抗压强度随时间显著降低，而微孔样品保持不变。12周后，两种PLGA/CAP样品均呈现球形微孔结构，抗压强度分别为12.2 Mpa(10：90)和4.3 Mpa(20：80)。在20：80的配方中也发现了水泥降解的迹象。总之，对于10：90和20：80的PLGA微球/帽水泥，所有的物理参数都在可行的范围内。12周后，PLGA被完全降解，并形成高度多孔的支架，但仍然坚固。
Calcium phosphate (CaP) cements show an excellent biocompatibility and often have a high mechanical strength, but in general degrade relatively slow. To increase degradation rates, macropores can be introduced into the cement, e.g., by the inclusion of biodegradable microspheres into the cement. The aim of this research is to develop an injectable PLGA microsphere/CaP cement with sufficient setting/cohesive properties and good mechanical and physical properties. PLGA microspheres were prepared using a water-in-oil-in-water double-emulsion technique. The CaP-cement used was Calcibon (R), a commercially available hydroxyapatite-based cement. 10:90 and 20:80 dry wt% PLGA microsphere/CaP cylindrical scaffolds were prepared as well as microporous cement (reference material). Injectability, setting time, cohesive properties and porosity were determined. Also, a 12-week degradation study in PBS (37 degrees C) was performed. Results showed that injectability decreased with an increase in PLGA microsphere content. Initial and final setting time of the PLGA/CaP samples was higher than the microporous sample. Porosity of the different formulations was 40.8% (microporous), 60.2% (10:90) and 69.3% (20:80). The degradation study showed distinct mass loss and a pH decrease of the surrounding medium starting from week 6 with the 10:90 and 20:80 formulations, indicating PLGA erosion. Compression strength of the PLGA microsphere/CaP samples decreased siginificantly in time, the microporous sample remained constant. After 12 weeks both PLGA/CaP samples showed a structure of spherical micropores and had a compressive strength of 12.2 MPa (10:90) and 4.3 MPa (20:80). Signs of cement degradation were also found with the 20:80 formulation. In conclusion, all physical parameters were well within workable ranges with both 10:90 and 20:80 PLGA microsphere/CaP cements. After 12 weeks the PLGA was totally degraded and a highly porous, but strong scaffold remained.