MicroSPECT/CT imaging and pharmacokinetics of 188Re-(DXR)-liposome in human colorectal adenocarcinoma-bearing mice.

Nanoliposome can be designed as a drug delivery carrier to improve the pharmacological and therapeutic properties of drug administration. 188 Re-labeled nano- liposomes are useful for diagnostic imaging as well as for targeted radionuclide therapy. In this study, the in vivo nuclear imaging, pharmacokinetics and biodistribution of administered nanoliposomes were investigated as drug and radionuclide carriers for targeting solid tumor via intravenous (i.v.) administration. The radiotherapeutics ( 188 Re-liposome) and radiochemotherapeutics ( 188 Re-DXR- liposome) were i.v. administered to nude mice bearing human HT-29 colorectal adenocarcinoma xenografts. 188 Re-liposome and 188 Re-DXR-liposomes show similar biodistribution profile; both have higher tumor uptake, higher blood retention time, and lower excretion rate than 188 Re-N,N-bis(2- mercaptoethyl)-N',N'-diethylenediamine (BMEDA). In contrast to tumor uptake, the area under the curve (AUC) value of tumor for 188 Re-liposome and 188 Re-DXR-liposome was 16.5- and 11.5-fold higher than that of free 188 Re- BMEDA, respectively. Additionally, 188 Re-liposome and 188 Re-DXR-liposome had a higher tumor-to-muscle ratio at 24 h (14.4±2 .7 and 17.14±4.1, respectively) than 188 Re-