Nanoliposomes are useful carriers in drug delivery. Radiolabeled nanoliposomes have potential applications in radiotherapy and diagnostic imaging. In this study, the biodistribution and pharmacokinetics of Re-188-BMEDA-labelled pegylated liposomes (RBLPL) and unencapsulated Re-188-BMEDA administered by the i.v. route in murine C26-colon tumour-bearing mice were investigated. MicroSPECT/CT images were performed to evaluate the distribution and tumor targeting of RBLPL in mice. For the biodistribution study, the highest uptake of liposome in tumors was 3.62% 0.73% at 24 h after RBLPL administration, and the tumor to muscle ratio of RBLPL was 7.1-fold higher than that of 188Re-BMEDA. With image analysis, the highest SUV in tumor was 2.81 +/- 0.26 at 24 h after injection of RBLPL. The Pearson correlation analysis showed a positive correlation of tumor targeting or uptake of RBLPL between biodistribution and microSPECT semi-quantification imaging analysis (r=0.633). The results of the pharmacokinetics revealed that the area under the tissue concentration-time curve (AUC) of RBLPL was 4.7-fold higher than that of unencapsulated Re-188-BMEDA. These results suggested the potential benefit and advantage of Re-188-labeled nanoliposomes for imaging and treatment of malignant diseases.
