高车前苷油水分配系数的测定及大鼠在体肠吸收动力学研究

Determination of Oil/Water Partition Coefficient and Absorption Characteristics of Homoplantaginin in Rat Intestine in situ

目的:测定高车前苷的油水分配系数,考察其在大鼠肠道的吸收动力学特性。方法:采用高效液相(摇瓶法)测定高车前苷在正辛醇(水、正辛醇)不同pH缓冲液体系中的油水分配系数;采用大鼠单向在体肠灌流法研究高车前苷吸收特性,用紫外分光光度法测定酚红浓度以标定体积,用高效液相色谱法测定高车前苷在大鼠不同肠段中的浓度。结果:在正辛醇(水体系中,高车前苷的油水分配系数为18.07(lgP=1.26),在正辛醇(缓冲液体系中分配系数受溶液pH值影响不大。高、中、低浓度高车前苷的吸收速率常数(Ka)、有效渗透系数(Peff)无显著性差异,且在大鼠各肠段的Ka,Peff均为空肠>十二指肠>回肠>结肠。结论:高车前苷在全肠段均有不同程度的吸收,其吸收机制为被动扩散。

Objective： To determine the oil/water partition coefficient of homoplantaginin and to investigate its absorption characteristics in various intestinal segments in rats. Method： A HPLC （shake flask method） was established to determine n-octanol/water partition coefficient of homoplantaginin in n-octanol （water and n-octanol） different pH solution; the intestinal absorption characteristics were detected by the in situ perfused rat intestinal model, the concentration of phenol red was determined by UV method while those of homoplantaginin was analysed by HPLC method. Result： The allocation ratio of homoplantaginin in octanol/water system was 18.07 （lgP = 1.26） and the PH of buffer solution had no influence on its distribution coefficient. The K and Poff of homoplantaginin showed jejunum 〉 duodenum 〉 ileum 〉 colon in four regions of intestine. The values of Ka and Peff of different drug concentrations had no significant influence, furthermore, the values of Ka and Pelf of different intestines showed to be jejunum 〉 duodenum 〉 ileum 〉 colon. Conclusion： Homoplantaginin can be absorbed in whole intestinal segment, the absorption mechanism may be related to passive diffusion.