Radiolabeling of RGD Containing Peptide by ¹⁸⁸Re and Its Biodistribution

A cyclic RGD containing peptide H-c(RGDyK) (Pc1) was labeled with ¹⁸⁸Re using fac-¹⁸⁸Re(CO)₃(H₂O)₃ as the precursor. The radiolabeling yield and radiochemical purity were more than 90% with in 30 min under 75 ℃. ¹⁹⁹Re -Pc1 was stable in CBS and PBS. RGD peptide had good binding -affinity to cancer cells (IC₅₀=84.9 nmol/L). Its biodistribution showed that ¹⁸⁸Re-Pc1 had a rapid blood clearance and was cleared mainly via the renal and hepatic route. ¹⁸⁸Re-Pc1 had high tumor uptake with a long time of tumor retention.