Sanguinarine metabolism and pharmacokinetics study in vitro and in vivo

Sanguinarine (SA) is a benzo[c] phenanthridine alkaloid which has a variety of pharmacological properties. However, very little was known about the pharmacokinetics of SA and its metabolite dihydrosanguinarine (DHSA) in pigs. The purpose of this work was to study the intestinal metabolism of SA in vitro and in vivo. Reductive metabolite DHSA was detected during incubation of SA with intestinal mucosa microsomes, cytosol, and gut flora. After oral (p.o.) administration of SA, the result showed SA might be reduced to DHSA in pig intestine. After i.m. administration, SA and DHSA rapidly increased to reach their peak concentrations (C_max , 30.16 ± 5.85, 5.61 ± 0.73 ng/ml, respectively) at 0.25 hr. Both compounds were completely eliminated from the plasma after 24 hr. After single oral administration, SA and DHSA rapidly increased to reach their C_max (3.41 ± 0.36, 2.41 ± 0.24 ng/ml, respectively) at 2.75 ± 0.27 hr. The half-life (T_1/2 ) values were 2.33 ± 0.11 hr and 2.20 ± 0.12 hr for SA and DHSA, respectively. After multiple oral administration, the average steady-state concentrations (C_ss ) of SA and DHSA were 3.03 ± 0.39 and 1.42 ± 0.20 ng/ml. The accumulation indexes for SA and DHSA were 1.21 and 1.11. The work reported here provides important information on the metabolism sites and pharmacokinetic character of SA. It explains the reasons for low toxicity of SA, which is useful for the evaluation of its performance.