以生物可分解高分子作為藥物載體已被廣為研究，近年來更開發了溫度敏感型水膠的藥物載體。溫感型水膠在加工上可以避免使用有機溶劑而改用大量的水，不僅可減少後製的純化步驟，更因為富含親水的特性，與活體組織相類似，因此可應用在親水性、親油性藥物的藥物傳遞，及不穩定的蛋白質分子傳輸如蛋白質、基因等組織工程方面。除此之外，水膠材料可具備生物相容性、生物可降解性、無毒性等性質，隨著不同官能基對外在環境會有不同應答，使得水膠的應用範圍更為廣泛。
因聚酯類降解的時間較好控制，作為藥物載體時具有良好、易控制釋放的優點而廣受到醫藥學界的重視。實驗中利用生物可分解材料甲氧基化聚乙二醇(methoxy poly(ethylene glycol), mPEG )與聚酯類以開環聚合方式( ring-opening polymerization )獲得具有生物可分解、生物相容性、有親疏水兩性鏈段的二團聯共聚物。將兩團聯共聚物水溶液經過分析，測其臨界微胞濃度，都低於10-3 mg/mL以下；粒徑分布在100~150nm之間；此外mPEG-PδVLA與mPEG-PγVLA的臨界成膠濃度皆為15wt%，而mPEG-PαVLA的臨界成膠濃度則為12wt%，實驗中使用的材料皆能在人體體溫37℃時形成水膠，尤其以mPEG-PαVLA的溫度適用範圍為最大(22℃~50℃)。mPEG-PδVLA、mPEG-PγVLA及mPEG-PαVLA在37℃緩衝溶液下，經過一個月的降解測試，約有50~80%的材料會被降解掉。以MTT進行細胞毒殺實驗時，發現無包藥的材料在培養一至兩天內，對老鼠的纖維母細胞( 3T3 cell )而言皆沒有明顯的毒性。水膠包埋替考拉寧( Teicoplanin )的藥物釋放， 在連續30 天觀察累積藥物釋放結果，以15 wt% mPEG-PγVLA水膠釋放最多可達32％，而15wt% mPEG-PαVLA水膠達到最慢釋放效果，30 天累積釋放28%，根據累積釋放曲線的觀察，可推測此水膠的釋放級數應為趨近於零級反應，故本實驗所研究的二團聯共聚物，應為一穩定且具有緩慢釋放效果的藥物釋放載體。

The biodegradable polymers used as drug delivery carriers have been widely researched in the past years. In recent years, one of the drug delivery carrier, hydrogel, has also been developed. Synthetic hydrogel without the organic solvent will be reduced the purify steps in the following formulation. Hydrogels can contain amount of water and resemble nature living tissue, so it can be used as drug delivery carrier for protein, hydrophilic and hydrophobic drugs. In additionally, they are biodegradability, biocompatibility, non-toxicity, and own the various responses to the environment. Hydrogels are extensively application of their unique behaviors.
In this study, we used the various mPEG-PVLA copolymers prepared by ring-opening polymerization of the mPEG, L-lactide, and various isomers of the δ-Valerolactone for the advanced drug delivery systems. Their structures will be measured by the GPC, 1H-NMR, DSC. Thermosensitive properties of the copolymers were tested using the tube inversion method. As a result, the sol–gel–sol transition temperature range could be varied, which might be very useful for its application as injectable drug delivery systems. The various hydrogel showed low cytotoxicity toward mouse fibroblasts 3T3 cell. After hydrogel particles were prepared, Teicoplanin is encapsulated. During 30 days accumulative drug release, 15 wt% mPEG-PγVLA has the most amount of release ratio 32%, and the most stable release is 15wt% mPEG-PαVLA, 28%. In thiis study, these amphiphilic diblock copolymers released Teicoplanin in a gradual mechanism and exhibited good stability, according to in vitro degradation behavior and in vitro drug release behavior. Because the materials degradation very slowly, the initial stage Teicoplanin release only by diffusion. As results, these hydrogels are very potential in long term controlled release of drug. controlled release system.

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