ABSTRACT
AIM To optimize the preparation of two inclusion compounds of erinacine A and to evaluate their stabilities.METHODS With feed ratio,milling time and milling speed as influencing factors,inclusion rate and yield as evaluation indices,the preparation was optimized by orthogonal test.The obtained inclusion compounds were characterized by infrared spectrophotometry and TLC,whose stabilities at high temperature (60 ℃),strong light (3 000 1x) and high humidity [(90 ±5)％] were investigated.RESULTS The optimal β-cyclodextrin inclusion conditions were determined to be 5 ∶ 1 for feed ratio,60 min for milling time,and 300 r/min for milling speed,the inclusion rate and yield were 20.66％ and 88.21％,respectively.The optimal hydroxypropyl-β-cyclodextrin inclusion conditions were determined to be 25 ∶ 1 for feed ratio,90 min for milling time,and 400 r/min for milling speed,the inclusion rate and yield were 69.25％ and 96.31％,respectively.The inclusion of Hericium erinaceus 80％ ethanol extract was physical process without composition change.At high temperature and strong light,two inclusion compounds' appearance showed no obvious change with little loss of erinacine A,which was just the contrary at high humidity.The inclusion effect of hydroxypropyl-β-cyclodextrin inclusion compound was better than that of β-cyclodextrin inclusion compound.CONCLUSION Both β-cyclodextrin and hydroxypropyl-β-cyclodextrin inclusion compounds of erinacine A exhibit good heat stability and light stability,but deliquescence can easily happen to them.
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Aim To investigate the stabilities and related mechanism of sulfobutyl ether-β-cyclodextrin liposomes loaded with asparaginase(ASDL).Methods Reverse evaporating method was used for the preparation of ASDL,and the acid-base stability,thermal stability,antitrypsin stability,plasma stability and storage stability of ASDL were tested.Moreover,fluorescence spectrum method was utilized to explore the stability enhancement mechanisms of ASDL.Results The results of stability showed that the acid-base stability,thermal stability,antitrypsin stability,plasma stability and storage stability of ASDL were all superior to asparaginase.Fluorescence experiment results indicated that the improved characteristics of ASDL might be related to the changes of the surrounding microenvironment of fluorescent chromophore or the structure of hydrophobic.Conclusion ASDL can effectively protect asparaginase from the external environment,such as hydrolase,pH,temperature and so on,to improve the stabilities of asparaginase.
ABSTRACT
Objective To prepare hyaluronic acid-nricase liposomes (UHLP) and to investigate the activity and stability of UHLP and uricase (UC) in vitro. Methods UHLP was prepared using reverse-phase evaporation and observed by transmission electron microscopy. The entrapment efficiency, particle size and zeta potential of UHLP were detected. The physical and chemical properties of UC in free UC and UHLP-including the optimum pi I and temperature-thermal stability-storage stability, pi I stability, stability to trypsinase, and stability to metal ions and organic compounds, were examined. In addition, the mechanism by which UHLP promotes UC activity was also explored. Results The mean entrapment efficiency of UIILP was (57. 2 ± 3. 93)% (n = 3), mean particle size was (322. 6 ± 8. 2) nm (n=3), and mean zeta potential was (–19.4 ± 1.7) mV (n = 3). UHLP was round or oval in shape and was evenly distributed under transmission electron microscopy. The optimum temperature of UC in UHLP and free UC was 40°C -and the optimum pH values of UC in UHLP and free UC was 8. 0 and 8. 5, respectively. Thermal stability, storage stability, pi I stability, stability to trypsin and stability to metal ions and organic compounds of UC in UHLP were better than those in free UC. The envelopment of UC with UHLP increased the activity of UC by reversing conformation and exposing active center of UC. Conclusion UHLP can not only enhance the activity but also improve the stability of UC in vitro.