Preparation,Stability and Sustained Release of Buckwheat Glycopeptide Liposomes
To prepare a sustained-release liposome of buckwheat glycopeptide(BG)and improve the bioavail-ability of BG,the stability of the prepared BG was firstly analyzed in this study,and reverse evaporation was used to prepared buckwheat glycopeptide liposomes(BGL),whose encapsulation process was optimized by response surface experiment.Subsequently,the stability,in vitro sustained release properties and biological activity of BGL were fur-ther investigated.The results indicated that temperature(20~80 ℃)had little effect on the activity of BG,but it declined rapidly in alkaline environment.Egg yolk lecithin was selected from five phospholipids to prepare BGL,and the optimum embedding conditions determined by the response surface experiment were as follows:the phospholipid to cholesterol mass ratio of 4.2∶1.0,lipid to drug ratio of 7.5∶1.0 and aqueous phase volume of 1 mL.Experiments carried out under these conditions led to the encapsulation rate of 72.64%for BGL.In vitro stability results indicated that the structural integrity of the BGL was easily destroyed under high temperatures(100 ℃).Conversely,BGL re-vealed a broad-spectrum pH(2~10)activity when the treatment time was 1 h and there was no significant effect(P>0.05)on leakage rate of BGL after repeated freezing and thawing five times.BGL had sustained-release char-acteristics in the simulated gastric and intestinal systems in vitro,and the cumulative release rate of 24 h was(84.50± 2.30)%and(60.17±1.42)%,respectively.