Study On Preparation And Stability Of Allicin Lipsomes

The embedded lipsome is one kind of novel microcapsule technology. After the biological active material was embedded by the lipid protoplasmic membrane made from the phospholipids (PL),its activity can be protected,its stability and biological assimilability can be obviously enhanced.The allicin with outstanding effectacy is the main effective component of garlic. It was applicated extensively in more and more fields,including food industry,pharmaceutical industry,biological research etc. However,the allicin is oxidized easily,has bad stability and its utilization degree is low. These factors limit its application greatly.This thesis is mainly about the research on the preparation technology of allicin lipsome and its stability.Firstly , the different purity membrane material of lipsome: phosphatidylcholine (PC) and phosphatidylethanolamine (PE) was prepared with combining methods of solvent extraction , adsorption method and column chromatography from rapseed oil degummed residues. The combination of single factor experiment and orthogonal method was used to make different kinds of PE at purity of 46.3% and 94.5%,and different kinds of PC,at purity of 66.7%,72.68% and 96.7%.Secondly,the preparation technology of the allicin liposome was studied. The HPLC and encapsulation detection method of allicin was established. The optimum preparation conditions dependenting on the single factor experiment and response surface experiment were as follows:The purity of PC was 66.7%,the ratio of PC and cholesterol was 6.12:1,concentration of allicins was 49.32mg,concentration of tween-80 was 215.54mg. In these conditions,the predictive value of allicin liposome encapsulation efficiency was 61.103% and the entrapment rate was 59.65%.Thirdly,the preparation technology and stability of the allicin lipsome freeze-drying powder was studied. The results showed that,mannitol was the best cryprotectants to allicin lipsome powder. When the ratio of PC and mannitol was 1:3, the effect of freeze-drying was the best. After stability experiment for 180ds,we detected that the hygroscopicity of lipsome increased at first and then decreased. The encapsulation and retention rate decreased gradually,and it kept steady after 120ds. However,the oxidation degree of PC was more and more aggravated. The condition of stability experiment illustrated that the lipsome freeze-drying power will get better preservation under the sistuation of cryogenic seal.Finally,surface modification of the allicin lipsome by using PEG2000,PVA and chitosan was explored preliminarily. Based on encapsulation , the best concentration of three coating materials was explored:when the concentration of PEG 2000 was 15%, the encapsulation was 71.16%; 0.7% is the best concentration for PVA,the entrapment was 79.10%. The coating effect of purified chitosan was better than unpurified chitosan. When concentration of purified chitosan was 1.5%,the best encapsulation was 82.64%. Research shows that the precipitation of the coated liposomes reduced significantly and the encapsulation was increased significantly. It means that this method significantly inhibited the gather and fusion of liposome and slowed the leakage of the drug.