芍药苷微乳溶液在大鼠在体肠的吸收动力学研究

目的考察芍药苷微乳溶液在大鼠在体肠吸收动力学特征,并与其水溶液进行比较,研究芍药苷微乳溶液在各肠段的吸收情况。方法采用大鼠在体肠吸收实验方法,用HPLC和UV法分别测定循环液芍药苷和酚红的浓度。结果在2～20mg.L-1浓度范围内芍药苷微乳溶液的吸收量与浓度成线性关系,吸收速率常数(Ka)值基本保持不变,芍药苷微乳溶液吸收药量和Ka均高于其水溶液;各肠段吸收有差异,结肠吸收药量和Ka明显高于十二指肠、空肠和回肠,Ka值依次为(0.501±0.031)、(0.086±0.003)、(0.108±0.017)、(0.114±0.006)h-1。结论芍药苷微乳溶液在肠道的吸收呈一级吸收动力学,吸收机制为被动吸收;芍药苷微乳溶液在空肠和结肠段吸收较好,且在肠道吸收好于芍药苷水溶液。提示可将芍药苷制成微乳制剂,以提高其生物利用度。

Studies on absorption kinetics of paeoniflorin microemulsion in rat's intestines

Aim To investigate the absorption kinetics of paeoniflorin microemulsion solution in rat intestines compared with the absorption of its solution,and to study the absorption properties of its microemulsion solution in rat intestines.Methods The intestine in rats was cannulated for in situ recirculation,in which HPLC and UV were respectively applied to measuring the concentration of the paeoniflorin in the flux and that of phenolsulfonphthalein in intestine perfusate.Results When the concentration raised from 2.0 to 20.0 mg·L-1,the uptake of paeoniflorin increased linearly.The absorption rate almost kept at the same level,besides,the uptake and absorption rate of paeoniflorin microemulsion solution are higher than paeoniflorin solution;different segments of intestine had different Ka and uptake,for instance,Ka and the uptake of colon were evidently higher than duodenum,jejunum,ileum,the Ka were(0.501±0.031),(0.086±0.003),(0.108±0.017),(0.114±0.006)h-1 respectively.Conclusions The absorption of paeoniflorin microemulsion solution is a first-order process with the passive diffusion mechanism;and the absorption of paeoniflorin microemulsion solution is better in ileum and colon;what's more,the paeoniflorin microemulsion solution's absorption is better than its solution in intestine.So paeoniflorin can be made into microemulsion praeparatum to elevate its bioavailability.