Biodistribution, pharmacokinetics and microSPECT/CT imaging of ¹⁸⁸Re-BMEDA-liposome in a C26 murine colon carcinoma solid tumor animal model

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 ¹⁸⁸Re-BMEDA-labelled pegylated liposomes (RBLPL) and unencapsulated ¹⁸⁸Re-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 ¹⁸⁸Re-BMEDA. These results suggested the potential benefit and advantage of ¹⁸⁸Re-labeled nanoliposomes for imaging and treatment of malignant diseases.