| Puerarin is a kind of Isoflavone which extracted from the rhizoma of Pueraria lobata (Willd.) Ohwi or Puer-qria thomsonii Benth. It possesses the efficacy of decreasing blood pressure and lowering blood sugar. It is a usual cardiovascular drug in clinic with high curative effects and less side effects, But its solubility in water is weak and it has poor oral absorption, most of the drugs will be excreted out of body as a original substance with excrement, so it had low bioavailability and its effect was limited.Orthogonal design was adopted to research the factors: concentration of ethanol, extraction time, ratio of ethanol to materials and times of extraction. The results of variance analysis showed that there were no significant difference between the factors, and according to the calculation results of the orthogonal design, it indicated that the best extracting condition is: 90% ethanol, ratio of ethanol to materials is 6, extract 1 times and 1.5 hour of each times. With the best extracting condition, the content of puerarin in the will be 1.72mg/g, and the transferring rate of puerarin is 87%.Macroreticular adsorbent were used in separating purify puerarin. By comparing the adsorption ratio and elution ratio, Macroreticular adsorbent type was chosen. The results of the experiment showed that D101 was better than D201 and CAD-40 macroreticular adsorbent in the performance of adsorption and elution. According to the yield of puerarin and the figure of HPLC, the concentration of the eluent and the procedure of the elution were chosen .To study the influence of the ratio (diameter to length) of chromatography column, velocity of flow and volume of eluent, orthogonal design was adopted. The result indicated that the best elution condition is choosing the chromatography column with ratio of diameter to length which is equaling to20: 1, Procedure of elution is: 3BV water , 1BV 5%ethanol , 4BV 30% ethanol .Collect theeluent of 30% ethanol and control the velocity of flow as 2ml/min. By this elution condition, the content of puerarin above 75% will be got.Based on comparison of efficiency of 4 kinds of solvent, acetic acid-methanol (1:1) was chosen as the solvent of recrystallization with 3 times. The crystal was identified by spectral analysis of MS ,IR and HNMR ,then its structure was deduced as 8- P -D-glucopyranosyloxy-4 -7-dihydroxy Isoflavone.Puerarin was chosen as a model drug, and according to the time of disaggregation and the homogeneity of dispersible tablet, the kinds and ratio and adding method of disintegrants and diluents were selected, So the best recipe is: MCC 22.7%, PGS30% , PPVP12% ,PVP1%, magnesium stearate 1% .We determined the dissolution time of the dispersible tablets. As a result, it can dissolve 90% in 10 minutes , and performed better dissolution than common tablets. Method of HPLC was developed in determining the contents of puerarin in the dispersible tablets. It has good sensitivity, nice specialization and it is easy to carry out.we determined the concentration of puerarin in plasma with HPLC method. We studied the Pharmacokinetics parameter and results showed that the drug movement in the body of puerarin dispersible tablets and puerarin tablet were according with two-compartment model : Tmax : 22.91 lmin, 43.306min, Cmax: 1.503ug/ ml , 0.772 Hg /ml, AUC: 282.702 ug ? min/ml, 267.942 ± 37.102ug ? min/ ml. and the drug movement in the body of dispersible tablets is better than puerarin tablet.
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