紫草素微乳改善大鼠小肠吸收的研究

目的:研究紫草素微乳( Skn-ME)对紫草素(Skn)实验性小肠吸收的改善作用.方法:采用大鼠单向灌流模型和离体外翻肠囊模型,紫外分光光度法测定肠灌流液中紫草素的浓度变化,研究紫草素微乳在大鼠小肠的吸收部位和吸收动力学特征.结果:大鼠在体小肠吸收实验中,紫草素微乳可被大鼠全肠段吸收,在十二指肠、空肠回肠及结肠各肠段的药物吸收速率常数(Ka)分别是0.213 4,0.221 8,0.217 6,0.221 1 min-1;药物表观吸收系数(Papp)分别是0.035 69,0.036 37,0.036 32,0.037 27 cm·min -,结肠段吸收最好(P＜0.001).在15 ～60 mg·L-1内,紫草素微乳在小肠的Ka不具有显著性差异.离体小肠吸收实验中,紫草素微乳吸收量和吸收率较紫草素提高106.1％,肠壁通透性增加123.02％.在15 ～60 mg·L-1内,吸收符合Fick's扩散定律,表现出一级动力学过程.结论:紫草素微乳通过提高肠壁通透性一定程度地改善其吸收,在小肠的吸收主要以被动扩散方式吸收.

Enhanced Absorption of Shikonin Microemulsion into Small Intestine in Rats

Objective: To investigate whether the absorption of shikonin can be enhanced by using shikonin microemulsion. Method: The uptake and intestinal permeability of shikonin and shikonin microemulsion were observed by using single-pass intestinal perfusion model and reverted gut sac method. Result: The shikonin microemulsion could be absorbed in whole intestinal segments. The absorption rate constants(Ka) of shikonin microemulsion at duodenum,jejunum,ileum and colon was 0.213 4, 0.221 8, 0.217 6, 0.221 1 min^-1, respectively;the apparent permeability coefficients(P_app) of was 0.035 69,0.036 37,0.036 32,0.037 27 cm·min^-1. Ka and P_app at colon were significantly higher than that at the other regions of intestine(P<0.001). Ka of shikonin microemulsion in intestine had no significant difference in the range of 15-60 mg·L^-1.The uptake and absorption rate of shikonin microemulsion increased with 106.1%; the permeability coefficient with 123.02%. The absorption process obeyed the Fick's law in the range of 15-60 mg·L^-1. Conclusion: The absorption shikonin microemulsion is enhanced by increasing the permeability through a passive mechanism.