Comparison of the enthalpic relaxation of poly(lactide-co-glycolide) 50:50 nanospheres and raw polymer
Comparison of the enthalpic relaxation of poly(lactide-co-glycolide) 50:50 nanospheres and raw polymer
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DOI：
10.1002/app.11109
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发表时间：
2002-11-21
影响因子：
3
通讯作者：
Mathiowitz, E
中科院分区：
文献类型：
--
作者：
Bailey, NA;Sandor, M;Mathiowitz, E
研究了聚丙交酯-乙醇酸酯（PLGA, 50:50）纳米微球作为受控药物递送系统的焓弛豫现象。样品在玻璃化转变温度（T-g）以下保存不同时间和温度。在39.2度的T-g下15度处发生了显著的弛豫。通过比较原料聚合物和采用新技术形成的纳米球的弛豫动力学，考虑了聚合物形态的影响。结果表明，纳米微球在玻璃化转变时的热容变化比原料聚合物大，平均弛豫时间比原料聚合物长，并讨论了这两个参数之间的关系。对于原料聚合物和纳米球，发现弛豫在室温下以显著的速率发生。因此，在亚环境温度下储存该系统对于保持系统的物理化学性质是重要的。(C) 2002 Wiley期刊有限公司
The phenomenon of enthalpic relaxation was evaluated for poly(lactide-co-glycolide) (PLGA, 50:50), in terms of storage of nanospheres for use as a controlled drug delivery system. Samples were stored for different times and temperatures below the glass transition temperature (T-g). Relaxation occurred at a significant rate up to 15 degrees below the T-g of 39.2degreesC. The effect of polymer morphology was considered by comparing the relaxation kinetics of the raw polymer with that of nanospheres formed using a novel technique. The nanospheres were shown to have a larger change in heat capacity at the glass transition and a longer average relaxation time than that of the raw polymer, and the relationship between these two parameters was discussed. For both the raw polymer and the nanospheres, relaxation was found to occur at a significant rate at room temperature. The storage of this system at subambient temperatures was therefore deemed important for maintaining the physicochemical properties of the system. (C) 2002 Wiley Periodicals, Inc.