Preparation And Token Of TP Liposomes

The liposomes ware prepared by reverse phase evaporation technique through using SPC and CH as membranous material. Encapsulation efficiency was determined with HPLC method. Using encapsulation efficiency as index of examination and designing an orthogonal experiment the optimal formulation of liposomes was determined. The structure of TP liposomes was observed under the optical microscope and transmission electron microscope ,and the mean particle size was measured by Submicron Particle Size Analyzer. The test of percutaneous absorption through rabbit skin in vitro was performed in Franz diffusion cell .We found that The optimum preparation formulation: SPC/CH(molar ratio): 2∶1; TP concentration: 10mg/ml; VE/ SPC(mass ratio): 1∶8; Oil-phase/ Water-phase(volume ratio): 3∶1. Under the formulation, the encapsulation efficiency was (50.81±1.92)%. The encapsulation efficiency of the liposomes could increase to 51.56% with PBS concentration of 3.4mmol/mL . The mean particle size of (198.14±12.29)nm and PI of (0.324±0.092) were smaller with PBS concentration of 6.7mmol/mL .So the concentration area of PBS: 3.4mmol/mL～6.7mmol/mL was selected. The structure of liposomes was observed under the microscope. The values of potential were -49～-46mV with Zeta Potential Analyzer. The permeation rate of TP solution was higher than that of TP liposomes. The cumulative release amount of TP solution rose more quickly accompanying with time, whereas cumulative release amount of TP liposomes rose more slowly. The cumulative release amount of TP solution was higher than that of TP liposomes at any time except in the first 0.5h and 1h.TP concentration hardly affected on permeation rate when it's10～20mg/mL under the same lipoid ratio, and the permeation rate could go up when concentration was increased to 30mg/mL. Changing the molar ratio of SPC and CH(from 1∶1 to 1∶0.5) hardly affected on permeation rate with the same TP concentrations. But permeation rate could be increased, when molar ratio of SPC and CH was 1∶0.3.The cumulative release amount of TP liposomes with higher encapsulation efficiency was obviously lower than that with lower.The operation of preparation is handy and credible as well as simple equipment, good recurrence. To embed medicament of water-solubility is appropriate. The factors of affecting on encapsulation efficiency is the ratio of SPC and CH, drug concentration, VE content, the volume ratio of organic solvent and TP solution, as well as concentration of buffer solution besides operation condition for preparation technics. TP liposomes can permeate through the rabbit skin rapidly up to a certain amount in a short time, then begins to realease drug slowly and permanently. The concentration of drug and PBS have influence on the particle size of TP liposomes. The cumulative release amount of drug is relative to encapsulation efficiency and content of CH et al .In this experiment, Liposoluable tea polyphenols(LTP) have been synthesized by means of acylation with lauroyl chloride.The results indicated that optimal conditions under which oil-soluable TP were synthesized are that lauroyl chloride and TP with molar number ratio 5∶1 react at 75~78℃under protection of nitrogen atmosphere. When Liposoluable tea polyphenols are embedded, the encapsulation efficiency of drug could be increased.