低分子量幾丁聚醣對微脂粒包覆斑蝥素物理穩定性之影響
The Effect of Low Molecular Weight Chitosan Study on the Physical Stability of Liposomes Encapsulation Cantharidin
中文摘要
微脂粒穩定性的研究在其應用發展上佔有舉足輕重的影響，因此本研究利用低 分子量水溶性幾丁聚醣來修飾微脂粒表面，觀測幾丁聚醣對微脂粒物理穩定性 的影響，同時也一並探討包覆抗癌藥物斑蝥素，幾丁聚醣對微脂粒包覆斑蝥素 的滲漏情形。
本實驗是以擠壓法(extrusion)製備微脂粒，並在製備完成的微脂粒溶液中添加 (吸附)幾丁聚醣。實驗結果顯示，添加幾丁聚醣於微脂粒溶液中，會使微脂粒的 界面電位下降，並且對微脂粒的初始粒徑會有增大的現象。此外，添加幾丁聚醣 會使微脂粒懸浮液濁度上升。另外，當幾丁聚醣的添加量大於1wt﹪時，在 25℃儲存溫度下，會加速微脂粒粒徑變大，造成所謂融合(fusion)的現象。至 於脂質脂雙層分子間的影響，由DSC 實驗中發現添加幾丁聚醣並不會影響微脂 粒之相轉移溫度。
關於斑蝥素滲漏實驗，無論是在25℃及 4℃下，傳統型與表面修飾型(添加 1wt﹪幾丁聚醣)微脂粒的粒徑與滲漏速率，都無明顯差別。另外，在 37℃下剪 應力流場(300sec-1、800 sec-1)環境下，無論是在粒徑及滲漏速率的比較，
實驗結果顯示傳統型與表面修飾型微脂粒都是無明顯之差異；不過，就不同剪 應力流場對傳統型與表面修飾型微脂粒的影響，兩者(傳統型與表面修飾型微脂 粒)皆顯示出在高剪切率(800 sec-1)的滲漏速率會高於低剪切率(300 sec-1)。
英文摘要
Physical stability of liposomes plays the critical roles in various stages of the applications and development of liposomes. In this study, we applied low
molecular weight chitosan to modify the liposomes surface, and investigated the physical stability of liposomes, Moreover, we encapsulated cantharidin to study the effects of chitosan which cause drug leakage.
In this study, the liposomes were prepared by the extrusion method. Chitosan was added to liposome dispersion to obtain the mixtures of various compositions. We showed that chitosan decreased zeta potential, and increased the size of
liposomes. Whereas, the addition of 1wt﹪chitosan had increased the size of liposome at 25℃, i.e. the behavior of fusion. Also, chitosan would increase the turbidity. Further, the DSC (differential scanning calorimeter) revealed that the addition of chitosan caused no difference in the intravesicle interaction.
To understand the behavior of cantharidin release, the conventional liposomes and modifier liposomes, revealed that there were no significant difference in size
and the rate of drug release at 25℃ and 4℃. Shear forces (shear rate in 300sec-1
、800sec-1) studies of the conventional liposomes and modifier liposomes showed that there were no significant difference in sizes and the rate of drug release at 37℃. Furthermore, both the conventional liposomes and modifier liposomes showed the rate of drug release was higher at shear rate in 800sec-1 than shear rate in 300sec-1.
