Preparation of 90Y-labeled different cyclic RGD peptides and evaluation in nude mice bearing human glioma xenografts

90Y-DTPA-Bz-NH-SA-c(KRGDf) and 90Y-DTPA-Bz-NH-c(ERGDf) were prepared, and their in vitro and in vivo properties were compared. ITLC and HPLC show that the labeling yields of both compounds are more than 99% under the optimal conditions(pH=5.5, reac- ting at 80 degree C for 20 min), and they are stable in vitro. The biodistribution in nude mice bearing human glioma xenografts reveals no significant difference between these two radiolabeled com- pounds on uptake for all of tissues at the experimental time points; and pretty good tumor targeting and in vivo stability; and two radiolabeled compounds are mainly excreted through kid- neys, partly excreted through hepatobiliary system. The experimental data demonstrate that both of cyclic KRGDf and cyclic ERGDf are suitable for the further development of polymerconjugated RGD peptide drugs. (authors)