Enhancing Tumor Targeting Efficiency of Radiolabeled Uridine (via) Incorporation into Nanocubosomal Dispersions

Background: Several nanosystems are currently being utilized to enhance the targeting efficiency of several cancer chemotherapeutic agents. This study was designed to improve tumor accumulation of iodine-125 (I-125)-uridine via incorporation into a nanocubosomal preparation. Materials and Methods: Nanocubosomes were prepared with the aid of Glycerol mono-oleate and Pluronic F127. Each prepared nanocubosomal preparation was adequately characterized by testing their particle size, polydispersity index (PDI), zeta potential (ZP), and transmission electron microscopy. The radiolabeling of uridine with I-125 was attempted using several oxidizing agents to achieve a high radiochemical yield, and the factors affecting the reaction yield were studied in detail. A comparative biodistribution study of free I-125-uridine and I-125-uridine loaded nanocubosomes was performed in normal and tumor bearing mice. The biodistribution was evaluated by intravenous injection of the sterile test solution, and animals were anesthetized and dissected at different time intervals postinjection (p.i.). Results: I-125-uridine was obtained in a high radiochemical yield (92.5% +/- 0.8%). Afterward, I-125 uridine was incorporated in a selected nanocubosome formulation, which showed nanosized cubic particles (178.6 +/- 0.90 nm) with PDI (0.301 +/- 0.04) and a ZP (34.35 +/- 0.4). The biodistribution studies revealed that I-125-uridine nanocubosomes showed higher tumor localization (3.1 +/- 0.4%IA/g at 2 h p.i. and a tumor/muscle ratio of 6.2) compared with the free I-125-uridine (2.7% +/- 0.4%IA/g at 2 h p.i. and a tumor/muscle ratio of 3.3). Conclusion: The results of this study confirmed that I-125-uridine loaded nanocubosome had better efficiency in targeting the tumor site, which makes it an adequate targeting agent for tumor imaging.