Studies on pharmacokinetic properties and intestinal absorption mechanism of sanguinarine chloride: in vivo and in situ.

Sanguinarine (SAN) is an alkaloid with multiple biological activities, mainly extracted from Sanguinaria canadensis or Macleaya cordata. The low bioavailability of SAN limits its utilization. At present, the nature and mechanism of SAN intestinal absorption are still unclear. The pharmacokinetics, single-pass intestinal perfusion test (SPIP), and equilibrium solubility test of SAN in rats were studied. The absorption of SAN at 20, 40, and 80 mg/L in different intestinal segments was investigated, and verapamil hydrochloride (P-gp inhibitor), celecoxib (MPR2 inhibitor), and ko143 (BCRP inhibitor) were further used to determine the effect of efflux transporter proteins on SAN absorption. The equilibrium solubility of SAN in three buffer solutions (pH 1.2, 4.5 and 6.8) was investigated. The oral pharmacokinetic results in rats showed that SAN was rapidly absorbed (T_max=0.5 h), widely distributed (Vz/F = 134 L/kg), rapidly metabolized (CL = 30 L/h/kg), and had bimodal phenomena. SPIP experiments showed that P-gp protein could significantly affect the effective permeability coefficient (P_eff) and apparent absorption rate constant (Ka) of SAN. Equilibrium solubility test results show that SAN has the best solubility at pH 4.5. In conclusion, SAN is a substrate of P-gp, and its transport modes include efflux protein transport, passive transport and active transport.