Biodistribution of Busulphan Loaded Biodegradable Nano-carrier Designed for Multimodal Imaging

Multifunctional nanocarriers for pathological site imaging and regulated drug delivery are increasingly promising for disease diagnosis and treatment. We developed a multifunctional theranostic nanocarrier system for anticancer drug delivery and molecular imaging. Superparamagnetic iron oxide nanoparticles (SPIONs) as an MRI contrast agent and busulphan as an antineoplastic agent were encapsulated into poly (ethylene glycol)-co-poly (caprolactone) (PEG-PCL) nanoparticles (NPs) via the emulsion-evaporation method. Busulphan entrapment efficiency was 83% and the drug release showed a sustained pattern over 10 hours. SPION loaded-PEG-PCL NPs showed contrast enhancement in T2 -weighted MRI with high r2* relaxivity. In vitro time-dependent cellular PEG-PCL NP uptake was observed in macrophage cells (J774A). PEG-PCL NPs were further functionalized with VivoTag 680XL Fluorochrome for in vivo fluorescence imaging for study of their biodistribution in Balb/c mice over 48 h. The results of real-time imaging were then confirmed by ex vivo organ imaging and histological examination. Generally, PEG-PCL NPs were highly distributed in the lungs until 4 h post intravenous administration, then redistributed and accumulated in liver and spleen until 48 h. No pathological impairment was found in the studied tissues. Thus, PEG-PCL NPs as biodegradable and biocompatible nanocarriers are an efficient multimodal imaging agent, offer high drug loading capacity, and provide the possibility of disease treatment.