Study on in situ intestinal absorption of active ingredients in Shuanghuanglian oral liquid in rats

Abstract

To study the intestinal absorption kinetics characteristic of the main four active ingredients in Shuanghuanglian oral liquid (SHL) and to investigate the influence of herbal compatibility in SHL on absorption of main effective ingredients. The in situ rat circulation model was used to investigate the concentration change differences of the four active components in SHL during perfusion. The absorption quantity of different concentrations of baicalin, chlorogenic acid, phillyrin and forsythoside A ranging from 40-160, 6-24, 3-12, 2.6-10.4 mg x L(-1) respectively was linear with concentration and showed no saturation at high concentration. The absorption rate constant K(a) and the hourly absorption percentages A were essentially unchanged. The pH changing from 5.0-7.43 had little influence on the absorption of phillyrin except baicalin, chlorogenic acid and forsythoside A. The calculated K(a) and A of the four active ingredients had no significant differences from that obtained after perfusing via duodenum, jejunum, ileum and colon; The calculated K(a) and A of baicalin in Scutellariae Radix (SR), chlorogenic acid in Lonicerae Japonicae Flos (LJF) and phillyrin in Forsythiae Fructus (FF) had no significant differences compared with that in SHL, but the calculated K(a) and A of forsythoside A in FF were obviously superior to that in SHL. The intestinal absorption of the four active ingredients in SHL was mainly passive diffusion and had no difference in different segments of rat intestine; the compatibility of SHL compounds changed the absorption of forsythoside A in FF obviously.