[Studies on absorption kinetics of scopoletin in rat stomachs and intestines].

OBJECTIVE: To study absorption kinetics of scopoletin in rat stomachs and intestines. METHOD: Rats was cannulated for in situ recirculation. UV and HPLC methods were used to determine the concentrations of phenolsulfonphthalein and scopoletin, respectively. RESULT: The absorption rates in rat stomachs at 2 h after administration was 76.31%; The absorption rates at colon, duodenum, ileum and jejunum were 46.25%, 40.54%, 38.21%, 32.77%, respectively. The absorption rate constant (Ka) at concentrations of 10.0144, 20.0288-40.0576 mg x L(-1) in intestine were 0.6434, 0.6137, 0.5970 h(-1), respectively. The Ka of scopoletin at pH of 6.0, 6.8 and 7.4 in intestine were 0.6217, 0.6033, 0.6137 h(-1), respectively. CONCLUSION: The concentrations and pH values of scopoletin solution had no distinctive effect on the absorption kinetics. The absorption of scopoletin was a first-order process with passive diffusion mechanism. Scopoletin was well absorbed at stomachs and intestines in rats. Colon was the best absorption site of scopoletin, which suggest that a sustained-release preparation should be suitable for this compound.