Abstract: THE RELATIONSHIP BETWEEN STRUCTURE AND BIODISTRIBUTION OF 99TcmPYRIDOXYLAMINO ACIDS FOR HEPATOBILIARY IMAGING AGENTSZhang Huaming Luo Shunzhong Liu Zhonglin Zhao Pengji(Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Chengdu 610003)ABSTRACTIn order to investigate the relationship between structure and biodistribution of 99Tcmpyridoxylamino acids(PA), pyridoxylLtryptophan(PHT), pyridoxylaminoLcystine(PHC) and pyridoxylaminotyrosine (PHY) are labelled with 99Tcm using Sn(Ⅱ) as a reductant. The labelling yields of 99TcmPA is better than 95% at pH=7.0. The partition coefficients as lipophilic parameter in the octanolwater system are determined. The biodistribution in male mice shows that 99TcmPA have fast blood clearance, but the difference is apparent in their hepatobiliary uptakes and intestinal accumulations. Particularly, there is a good correlation between the hepatobiliary uptake and the partition coefficient. The larger the partition coefficient, the higher the lipophilicity. This result may be valuable for developing new 99TcmPA of hepatobiliary imaging agent.Key words 99Tcmpyridoxylamino acids 99TcmPA) hepatobiliary imaging agent structure biodistribution relationship