The demand for tailored, disease-adapted, and easily accessible radiopharmaceuticals is one of the most persistent challenges in nuclear imaging precision medicine. In this study, two radiotracers were developed to bind SPECT and PET radionuclides.

Methotrexate (MTX) is a folic acid antagonist routinely used in cancer treatment, characterized by poor water solubility and low skin permeability. These issues could be mitigated by using drug delivery systems, such as functionalized gold nanoparticles (AuNPs), known for their versatility and unique properties. This study aimed to develop multi-shell AuNPs functionalized with MTX for the improvement of MTX antitumoral, antioxidant, and biocompatibility features. Stable phosphine-coated AuNPs were synthesized and functionalized with tailored polyethylene glycol (PEG) and short-branched polyethyleneimine (PEI) moieties, followed by MTX covalent binding. Physicochemical characterization by UV-vis and Fourier-transform infrared spectroscopy (FTIR) spectroscopy, dynamic light scattering (DLS), scanning transmission electron microscopy (STEM), and X-ray photoelectron spectroscopy (XPS) confirmed the synthesis at each step. The antioxidant activity of functionalized AuNPs was determined using DPPH radical scavenging assay, ferric ions' reducing antioxidant power (FRAP), and cupric reducing antioxidant capacity (CUPRAC) assays. Biocompatibility and cytotoxicity were assessed using MTT and LDH assays on HaCaT human keratinocytes and CAL27 squamous cell carcinoma. MTX functionalized AuNPs demonstrated enhanced antioxidant activity and a pronounced cytotoxic effect on the tumoral cells compared to their individual components, highlighting their potential for improving cancer therapy.

Although niflumic acid (NA) is one of the most used non-steroidal anti-inflammatory drugs, it suffers from poor solubility, low bioavailability, and significant adverse effects. To address these limitations, the complexation of NA with cyclodextrins (CDs) is a promising strategy. However, complexing CDs with low molecular weight drugs like NA can lead to low CE. This study explores the development of inclusion complexes of NA with 2-hydroxypropyl-β-cyclodextrin (2HP-β-CD), including the effect of converting NA to its sodium salt (NAs) and adding hydroxypropyl methylcellulose (HPMC) on complex formation. Inclusion complexes were prepared using co-evaporation solvent and freeze-drying methods, and their CE and Ks were determined through a phase solubility study. The complexes were characterized using physicochemical analyses, including FT-IR, DSC, SEM, XRD, DLS, UV-Vis, ¹H-NMR, and ¹H-ROESY. The dissolution profiles of the complexes were also evaluated. The analyses confirmed complex formation for all systems, demonstrating drug–cyclodextrin interactions, amorphous drug states, morphological changes, and improved solubility and dissolution profiles. The NAs-2HP-β-CD-HPMC complex exhibited the highest CE and Ks values, a 1:1 host-guest molar ratio, and the best dissolution profile. The results indicate that the NAs-2HP-β-CD-HPMC complex has potential for delivering NA, which might enhance its therapeutic effectiveness and minimize side effects.

Hybrid nanomaterials that integrate surface functionality, colloidal stability, and efficient electron-transfer pathways are highly attractive for improving electrochemical sensing performance. Herein, we report the fabrication and evaluation of polyethyleneimine-functionalized gallium nitride nanoparticles (GaN) decorated with gold nanoparticles (GaN-PEI-Au) as a tunable electrode modifier for enhanced differential pulse voltammetry (DPV) detection of erythromycin. Branched polyethyleneimine was employed as a multifunctional interfacial layer to stabilize GaN dispersions, introduce amine-rich surface chemistry, and enable in situ gold nanoparticle formation at the GaN-PEI. The optimized GaN-PEI-Au material exhibited high colloidal stability, a characteristic Au localized surface plasmon resonance in the ~520–525 nm range, and well-defined Au nanoparticles attached to the GaN surface. When applied as an electrode coating, GaN-PEI-Au significantly enhanced the erythromycin oxidation response compared to bare Au and GaN-PEI interfaces, consistent with synergistic increases in electroactive surface area and interfacial charge-transfer efficiency. Under optimized DPV conditions, GaN-PEI-Au-modified electrodes enabled quantitative erythromycin determination with a linear range of 5 nM–2 µM (R² = 0.990), sensitivity of 1.32 × 10⁻³ µA nM⁻¹, and a limit of detection of 52.5 nM, while maintaining stable baseline behavior during repeated scans. The reported GaN-PEI-Au nanocomposites represent a robust platform for sensitive electrochemical detection of pharmaceutical compounds.