The Effects and Mechanism of Protectants on the Liposomal Formulation of Superoxide Dismutase

• Main Authors: Jui-Nan Thung, 董瑞南
• Other Authors: Yu-Li Lo
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/68184606404217882899

碩士 === 嘉南藥理科技大學 === 生物科技系暨研究所 === 91 === 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.