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首页> 外文期刊>Biomaterials >Characterization of co-polymers of lactic and glycolic acid for supercritical fluid processing.
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Characterization of co-polymers of lactic and glycolic acid for supercritical fluid processing.

机译：乳酸和乙醇酸共聚物的表征，用于超临界流体加工。

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摘要

Polymers of lactic and glycolic acid are often used for the production of injectible microparticles with controlled drug release. In the variety of processes used for the microparticle formulation, the Aerosol Solvent Extraction System (ASES) is rather special. Microparticle formation and drying take place in one step by precipitating a methylene chloride solution of the polymer in supercritical CO2. This process sets special requirements to the polymers in crystallinity, solubility, and thermal behavior that are best fulfilled by blocked copolymers. This study investigates a number of lactide-co-glycolide polymers with blocked distribution of the co-monomers by NMR spectroscopy and powder diffraction. The molar ratios are determined by 1H-NMR spectroscopy to verify the manufacturer's declarations of the purchased specimens. Additionally, the block length is determined by application of 13C-NMR. Therefore, a method reported in the literature was modified and evaluated in order to calculate the length of lactide and glycolide sequences in the polymer. Furthermore, this study looks at the impact of synthesis conditions on block length and crystallinity, and the impact of the blocking on both, crystallinity and solubility of the polymers.
机译：乳酸和乙醇酸的聚合物通常用于生产可控药物释放的可注射微粒。在用于微粒制剂的各种方法中，气溶胶溶剂萃取系统（ASES）相当特殊。通过沉淀聚合物在超临界CO2中的二氯甲烷溶液，一步即可完成微粒的形成和干燥。该方法对聚合物的结晶度，溶解度和热行为提出了特殊要求，嵌段共聚物可以最好地满足这些要求。这项研究通过NMR光谱和粉末衍射研究了许多共聚单体分布受阻的丙交酯-共-乙交酯聚合物。摩尔比通过1 H-NMR光谱确定，以验证制造商对所购买样品的声明。另外，通过应用13 C-NMR确定嵌段长度。因此，对文献中报道的方法进行了修改和评估，以计算聚合物中丙交酯和乙交酯序列的长度。此外，本研究着眼于合成条件对嵌段长度和结晶度的影响，以及嵌段对聚合物的结晶度和溶解度的影响。

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