Distrubution and excretion of protopine in rats by RP-HPLC method / 中国药理学通报

ABSTRACT

AIM To study the distrubution and excretion of protopine in rats. METHODS Reversed phase high performance liquid chromatographic method (RP HPLC) was developed for determining the level of protopine in rats. The analytical column were packed with 5 ?m C 18 . The mobile phase was a mixture of methanol, water and 10% acetic acid (80∶20∶2), in which the pH was modulated to 5 6 with 15% ammonia. Protopine biological samples were isolated well, in which two extraction with ether under basical condition and an extraction with 0 02 mol?L -1 sulfuric acid were performed, respectively. The content of protopine in the biological sample was measured by an UV detector at 285 nm. The distrubution and excetion of protopine have been investigated in rats after intravenous administration 10 mg?kg -1 . RESULTS Protopine distrubuted in many tissues after iv a dose of 10 mg?kg -1 . The higher level of protopine was found in lung, kidney, spleen and brain, and the highest was observed in lung at 5, 15 minutes after administration. However the top level tissue was testicle at 3 h, which may be due to small blood circulation. The excretion of the parent compound in urine was 36 87% of dose, but the excretion of the parent compound in feces and bile was less than 1% of dose. Plasma protein binding was less than 5%. CONCLUSION The distrubution of protopine is extensive and the parent compoud was mainly excreted by urine and plasma protein binding was low.