Research Of Bovine Serum Albumin Liposomes

Objective to study the preparation technology of BSA liposome and optimize prescription of the BSA freeze-dried liposome with bovine serum albumin (BSA) as a model drug. In order to improve the stability and extend the shelf life of BSA. The follow works have been done in the thesis:Firstly, establish an method for the determination of encapsulation efficiency of BSA liposome. High-speed centrifuge method were used to separate the free drug and liposome, and determine the encapsulation efficiency of BSA liposome by coomassie brilliant blue method.Then, aim to determ the preparation procedures of BSA liposome by reverse phase evaporation technique, using phosphatidyl choline (PC) and cholesterol (CH) as membranous materials, ether as organic phase, pH of phosphate buffer solution was7.4as hydrated vehicle. Different lyophilize agents were added the BSA liposome, the colour, disperse pattern, encapsulation efficiency and particle size of the obtained freeze-dried samples were observed. The ratio of trehalose/PC is6:1, encapsulation efficiency of the BSA freeze-dried liposome is67.20%. The stability was calculated and it was found that the BSA freeze-dried liposome stored under4℃for90days, the colour, particle size and encapsulation efficiency had no significant changes, and the storage stability was good.Finally, response surface methodology was employed to optimize prescription of the BSA freeze-dried liposome. The effects and interaction of three factors on encapsulation efficiency and drug loading of freeze-dried liposome, such as cholesterol(CH)/phosphatidyl choline(PC), bovine serum albumin(BSA) concentration, trehalose concentration, were investigated by method of central composite design. Quadratic regression models were set up according to the experimental data. And response surfaces were delineated on the basis of best-fit mathematic models. The optimal technology conditions of BSA freeze-dried liposome are as follows:the ratio of CH/PC is0.25, BSA concentration is3.40mg/mL and trehalose concentration is33.00mg/mL. The results show that encapsulation efficiency and drug loading of the BSA freeze-dried liposome are63.10%and26.91%respectively under the optimal conditions.