Radioiodination, biodistribution and pharmacokinetics of berberine in mice

Berberine was iodized by iodine monochloride, followed by an isotopic exchange reaction with Na125I. The radiochemical purity and in vitro and in vivo stability were quite satisfactory. The biodistribution in mice showed that the concentration of 125I-labeled berberine was high in the gallbladder and gastrointestinal system, as compared to other organs. Berberine was metabolized in the liver, partly excreted through the hepatobiliary tract, and underwent a process of hepatoenteral circulation. Its main route of elimination was renal excretion. Blood concentrationtime curve was fitted with an open two-compartment model. The plasma protein binding rate was (48±3.8)%. The results indicated that the radioiodinated berberine has similar in vivo behavior and pharmacokinetics to berberine reported before. The novel radioiodination is a convenient method to study in vivo behavior of such alkaloids.