PEGylated Gambogic Acid Nanoparticles Enable Efficient Renal-Targeted Treatment of Acute Kidney Injury.

Acute kidney injury (AKI) is a common clinical syndrome lacking effective pharmacotherapy. Gambogic acid (GA), as an active ingredient of herbal medicines, exhibits antioxidant and anti-inflammatory effects that benefit the treatment of AKI, but its poor aqueous solubility limits effective renal delivery. We, for the first time, developed GA-based nanoparticles (GA-NPs) with preferential renal uptake for AKI treatment. By PEGylating with NH2-PEG5000-NOTA, hydrophobic GA was self-assembled into ∼4.5 nm nanoparticles, which showed the enhanced renal accumulation in AKI models from PET images. Importantly, the in vitro cell assays and in vivo tests of the two AKI models have confirmed the obvious nephroprotective effects and biosafety of GA-NPs. Therefore, this work indicates that GA-NPs can be a promising therapeutic candidate for the management of AKI.

Synthesis and Preclinical Evaluation of a 68Ga-Labeled Pyridine-Based Benzamide Dimer for Malignant Melanoma Imaging.

Benzamide (BZA), a small molecule that can freely cross cell membranes and bind to melanin, has served as an effective targeting group for melanoma theranostics. In this study, a novel pyridine-based BZA dimer (denoted as H-2) was labeled with 68Ga ([68Ga]Ga-H-2) for positron emission tomography (PET) imaging of malignant melanomas. [68Ga]Ga-H-2 was obtained with high radiochemical yield (98.0 ± 2.0%) and satisfactory radiochemical purity (>95.0%). The specificity and affinity of [68Ga]Ga-H-2 were confirmed in melanoma B16F10 cells and in vivo PET imaging of multiple tumor models (B16F10 tumors, A375 melanoma, and lung metastases). Monomeric [68Ga]Ga-H-1 was prepared as a control radiotracer to verify the effects of the molecular structure on pharmacokinetics. The values of the lipid-water partition coefficient of [68Ga]Ga-H-2 and [68Ga]Ga-H-1 demonstrated hydrophilicity with log P = -2.37 ± 0.07 and -2.02 ± 0.09, respectively. PET imaging and biodistribution showed a higher uptake of [68Ga]Ga-H-2 in B16F10 primary and metastatic melanomas than that in A375 melanomas. However, the relatively low uptake of monomeric [68Ga]Ga-H-1 in B16F10 tumors and high accumulation in nontarget organs resulted in poor PET imaging quality. This study demonstrates the synthesis and preclinical evaluation of the novel pyridine-based BZA dimer [68Ga]Ga-H-2 and indicates that the dimer tracer has promising applications in malignant melanoma-specific PET imaging because of its high uptake and long-time retention in malignant melanoma.