| Summary: | 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.
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