ABSTRACT
Double cannulation model of conscious rat allowing simultaneous collection of mesenteric lymph and jugular venous blood was established to investigate the intestinal lymphatic transport of breviscapine orally administered in rat. The concentrations of breviscapine in plasma and lymph were determined by HPLC. The pharmacokinetics of breviscapine after oral and intravenous administration was evaluated in the conscious rat model. It was observed that scutellarin distributed from blood circulation to lymphatic system after intravenous injection. The cumulative lymphatic transport amount within 12 h was (2.78 +/- 0.25) microg, equivalent to 0.0792% of intravenous dose. After oral administration of scutellarin to double-cannulation rats, the cumulative lymphatic transport amount within 12 h was (0.92 +/- 0.08) microg, equal to 0.0083% of oral dose. The absolute bioavailability of breviscapine orally administered to double-cannulation rats was 4.91%, indicating that scutellarin was mainly absorbed into the bloodstream through the portal vein. Lymphatic transport of scutellarin appears to reflect high affinity for the lymph lipoproteins to chylomicron. This study provided a biopharmaceutics basis for developing oral lipid delivery system for the promotion of intestinal lymphatic transport to improve oral bioavailability of breviscapine.