Studyies On Liposome Of Astragalus Extract

A modified ethanol injection-extrude method was developed to prepare liposome, which contains effective components of Astragalus. The content of astragalus extraction and the liposome entrapment efficiency were accurately determined. Liposome physicochemical properties, stabilities, and primary pharmacodynamics were also investigated in this paper.Two colorimetric methods were established in quantitative determination of total sapoins and flavonoids. The content of the two kinds of effective components added up to 71.66% in the astragalus extraction. Total saponins were separated and purified by D101 macroreticular resin, which eliminating the interference from other impurities for the quantitative test, then measured by spectrophotometry with venina-perchlonic acid and the result is 38. 28%. The total flavonoids were determined by another colorimetric method directly, the result is 33. 37%.For further preparation, astragaloside IV and formononentin, two important index components, were determined by HPLC. The content of astragaloside IV was 3.84mg/ml measured by HPLOELSD. It is obviously prior to HPLC-UV and give rise to a new quantitativeanalysis of astragaloside IV. The content of formononentin was 0. 54mg/ml determined by HPLC-UV at 250nm.On the basis of single-factor test for effective preparation procedures and formulation constituents, a uniform design was carried out to obtain the optimum component of liposome with high entrapment efficiency (EN%) and good stability. The EN% of astragaloside IV is 34. 56% and EN% of formononentin is 29. 86%. After extruding by Lipex-extruder, the mean size of the liposome decreased to 210nm,with low polydispersion index. This method was proved suitable for liposome preparation and sterilization through 220nm film.In accelerated test, it was found that the liposome suspension was stable at low temperature in oxygen-free atmosphere without light. Primary pharmacodynamics test showed that the liposome of astragalus extraction could prolong duration time in trachea closed mice; obviously alleviate acute myocardial ischemia induced by pituitrin and isoprenaline in rats. In addition , the activity of SOD is increased and the content of MDA is decreased in ischemic myocardium caused by isoprenaline.