Hypericin-loaded in modified theranostic liposome nanoplatform: a preliminary in vivo study of targeting and diagnosis

Modified theranostic liposomes were created by combining phospholipid 1,2-dipalmitoyl-sn-3-glycerol-phosphatidylcholine with two previously modified Pluronic^® copolymers covalently linked with spermine and folic acid to carry and stabilize the photosensitizer compound hypericin. After physicochemical characterization, the photocytotoxicity was evaluated against different cancer and healthy cells presenting a strong photodynamic effect. The formulation exhibited no photoactivity without illumination and without hypericin. In vivo, pharmacokinetics biodistribution examined the uptake and theranostic potential of this nanoformulation after its intravenous administration in animal models. Fluorescence images revealed the maximum fluorescence between 0.5–4 h post-tail vein injection, making it an appropriate period for photodynamic treatment. The fluorescence of the entire body was monitored for at least 3 days, indicating that the theranostic procedures can be performed within the 0.5–4 h range after administration, after which the intensity decreases, indicating a potent metabolic ability with no significant side effects. The fluorescence images of the main organs consistently showed a signal during the 1st day of its application. After 48 h, only residues of the modified theranostic formulation were detected in the lungs and thyroid. The promising pharmacokinetics observed in our preliminary studies highlight the potential of this system, making it a worthy candidate for further investigation with tumor models.