Miscibility of Bioerodible Polyphosphazene/Poly(lactide-co-glycolide) Blends
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- 作者：Nicholas R. Krogman ; Anurima Singh ; Lakshmi S. Nair ; Cato T. Laurencin ; Harry R. Allcock ;
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- 刊名：Biomacromolecules
- 出版年：2007
- 出版时间：April 2007
- 年：2007
- 卷：8
- 期：4
- 页码：1306 - 1312
- 全文大小：448K
- 年卷期：v.8,no.4(April 2007)
- ISSN：1526-4602
文摘
We have previously demonstrated the feasibility of blending bioerodible polyphosphazenes with poly(lactide-co-glycolide) (PLGA) to form versatile polymeric materials with altered bioerosion properties. These studiesdemonstrated the effective neutralization of the acidic degradation products of PLGA by the polyphosphazenehydrolysis products. In the present study, five new polymers of dipeptide polyphosphazenes poly[(ethyl glycinato)x(glycyl-ethyl glycinato)yphosphazene] and novel blends of these polyphosphazenes with poly(lactide-co-glycolide)(PLGA) were synthesized and fabricated. The miscibility was analyzed using differential scanning calorimetryand scanning electron microscopy. Hydrogen bonding within the blends was assessed by attenuated total reflectanceinfrared spectroscopy. The phosphazene component of the blend contained varying ratios of the glycyl-glycineethyl ester to the glycine ethyl ester. Poly[(ethyl glycinato)0.5(glycine ethyl glycinato)1.5phosphazene formedcompletely miscible blends with PLGA (50:50) and PLGA (85:15). This is ascribed to the multiple hydrogen-bonding sites within the side groups of the polyphosphazene. The components of the blend act as plasticizers foreach other because a glass transition temperature for each blend was detected at a lower temperature than foreach individual polymer. A hydrolysis study showed that unblended solid poly[(ethyl glycinato)0.5(glycyl ethylglycinato)1.5phosphazene] hydrolyzed in less than 1 week. However, the blends degraded at a slower rate thanboth parent polymers. This is attributed to the buffering capacity of the polyphosphazene hydrolysis products,which increases the pH of the degradation media from 2.5 to 4, thereby slowing the degradation rate of PLGA.