Comparative study on the excretion of vitexin-4''-O-glucoside in mice after oral and intravenous administration by using HPLC.

The aim of the present study was to characterize the excretion of pure vitexin-4"-O-glucoside (VOG) in mice following oral and intravenous administration at a dose of 30 mg/kg. A sensitive and specific HPLC method with hespridin as internal standard, a Diamonsil C18 column protected with a KR C18 guard column and a mixture consisting of methanol-acetonitrile-tetrahydrofuran-0.1% glacial acetic acid (6:2:18:74, v/v/v/v) as mobile phase was developed and validated for quantitative analysis in biological samples. VOG could be excreted as prototype in excreta including urine and feces after both routes of administration, and the cumulative excretion of VOG was 24.31 ± 11.10% (17.97 ± 5.59% in urinary excretion; 6.34 ± 5.51% in fecal excretion) following oral dosing and 5.66 ± 3.94% (4.78 ± 3.13% in urinary excretion; 0.88 ± 0.81% in fecal excretion) following intravenous dosing. The results showed that the elimination of VOG after the two routes was fairly low, which meant that VOG was metabolized as other forms and the elimination after oral dosing was almost 4.3-fold that after intravenous dosing. For both routes of administration, VOG excreted as prototype in urine was much more than that in feces, nearly 2.83-fold for oral administration and 5.43-fold for intravenous administration, which should be attributed to enterohepatic circulation. Taken together, renal excretion was the dominant path of elimination of VOG for oral and intravenous administration in mice and biliary excretion contributed less.