本篇論文主要探討使用逆相蒸發法以及冷凍乾燥方式，將超氧化物歧化酶(Superoxide dismutase,SOD)包覆在不同電荷形式之微脂粒劑型中，並進一步研究在製備過程添加界面活性劑與糖類等冷凍保護劑後，對SOD微脂粒的物理化學特性以及體外釋放、加速安定性試驗之影響。從實驗結果發現，微脂粒粒徑大小範圍約在300nm-800nm之間，評估蛋白質活性分析時，發現對SOD酵素的包覆效率可高達92%。而2.0%－3.6%之溼度殘存量並不會影響SOD 的酵素活性表現。在紅外線光譜分析的結果發現，有保護劑的存在下將會有助於提昇SOD的二級結構穩定性；熱分析結果說明保護劑與脂質、蛋白質有結合作用。觀察體外釋放試驗，所有微脂粒劑型中的藥物有延遲釋放的現象，持續釋放時間可長達72小時以上。安定性試驗結果顯示，添加糖類與界劑保護劑之微脂粒劑型，會比不添加保護劑的微脂粒劑型有更好的穩定性，在恆溫恆濕環境下保存一個月，酵素活性並沒有很明顯地損失。綜合實驗所得到的結果，可提供一種可提高藥物包覆量之微脂粒製備方法，以及藉由添加雙糖類與界面活性劑等保護劑之策略，讓超氧化物歧化酶在製備與儲存過程中能夠更加地穩定。 The aim of this study was to develop novel superoxide dismutase (SOD)-incorporated liposomal formulations with neutral, positive, and negative charges. These liposomes were prepared by modified reverse-phase evaporation method and freeze-dried methods. The effects of surfactants and sugars as stabilizers on the physical and chemical properties of liposomal SOD formulations were investigated.Our experimental results showed that the measured particle size distribution of SOD-liposomes was ranged from 300 nm to 800 nm. The SOD activity assay was determined and the encapsulation efficiency of SOD in liposomes can reach up to 92%. The residual moisture content within the range of 2.0∼3.6﹪did not affect the SOD enzyme activity. In addition, Fourier-transform infrared (FT-IR) spectroscopy was used to analyze the secondary structure of SOD in the liposomal formulations. The quantitative analysis demonstrated that the presence of the stabilizers improved the stability of SOD secondary structure. The results from differential scanning calorimetry (DSC) analysis showed that the lyoprotectants not only exhibited the interaction with lipids and SOD, but also improved glass transition temperature (Tg) of products. Finally, on the basis of in vitro release study, SOD-loaded liposomes displayed the prolonged release of more than 72 hours. The stability tests showed that SOD-loaded liposomes with protectants maintained more SOD activity than those formulations without protectants. No significant loss of the SOD activity was observed within 1 month storage. These results suggest that the strategy of designing liposomal SOD formulations with disaccharides and surfactants may optimize SOD stability and provide an alternative dosage form of SOD.
