Preparation, characterization and evaluation of [125I]-pirarubicin: A new therapeutic agent for urinary bladder cancer with potential for use as theranostic agent

Preparation and evaluation of radiolabeled acetaminosalol microspheres: A new potential selective radiotracer for ulcerative colitis early diagnosis

Acetaminosalol labeling reaction with technetium-99m was optimized, and the radiocomplex was obtained in a high radiochemical yield of 98.9 ± 0.6% and high stability (>30 h). The tracer was characterized, and its binding to the PPARγ receptor was assessed in silico. To reduce radiation exposure to non-target organs and increase accumulation in the colon, the tracer was formulated as pH-sensitive microspheres with a mean particle size of 201 ± 2.1 μm, a polydispersity index of 0.18, a 25.3 ± 3.6 zeta potential, and 98.6 ± 0.33% entrapment efficiency. The system suitability was assessed in vivo in normal and ulcerative rats, and the biodistribution profile in the colon showed 56.5 ± 1.4% localization within 4 h. Blocking study suggested the selectivity of the tracer to the target receptor. Overall, the reported data encouraged the potential use of the labeled microspheres to target ulcerative colitis.

Targeted hollow pollen silica nanoparticles for enhanced intravesical therapy of bladder cancer

Bladder cancer (BC), such as non-muscle invasive bladder cancer (NMIBC), has a significantly high recurrence rate even after intravesical therapy because traditional intravesical chemotherapeutic drugs have short retention time in the bladder and lack efficient uptake in BC cells. Pollen structure usually shows potent adhesion ability to tissue surfaces, different from traditional electronic interaction or covalent binding. 4-Carboxyphenylboric acid (CPBA) has high affinity to sialic acid residues that are overexpressed on BC cells. In the present study, hollow pollen silica (HPS) nanoparticles (NPs) were prepared and modified with CPBA to form CHPS NPs, which could be further loaded with pirarubicin (THP) to form THP@CHPS NPs. THP@CHPS NPs showed high adhesion to skin tissues and could be more efficiently internalized by a mouse bladder cancer cell line (MB49) than THP, inducing more significant apoptotic cells. After intravesical instillation into a BC mouse model through an indwelling catheter, THP@CHPS NPs could more significantly accumulate at the bladder than THP at 24 h post-instillation, and after 8 days of intravesical treatments, magnetic resonance imaging (MRI) revealed that the bladders treated with THP@CHPS NPs showed more smooth bladder lining and more reduction in size and weights than those with THP. Moreover, THP@CHPS NPs exhibited excellent biocompatibility. THP@CHPS NPs hold great potential for intravesical treatment of bladder cancer.

Preparation and evaluation of radiolabeled gliclazide parenteral nanoemulsion as a new tracer for pancreatic β-cells mass

PURPOSE

The present investigation aims to develop and evaluate a radiopharmaceutical for targeting and assessing β-cells mass based on gliclazide, an antidiabetic drug that specifically binds the sulfonylurea receptor unique to the β-cells of the pancreas.

METHODS

Conditions were optimized to radiolabel gliclazide with radioiodine via electrophilic substitution reaction. Then, it was formulated as a nanoemulsion system using olive oil and egg lecithin by hot homogenization followed by ultrasonication. The system was assessed for its suitability for parenteral administration and drug release. Then, the tracer was evaluated in silico and in vivo in normal and diabetic rats.

RESULTS AND CONCLUSIONS

The labeled compound was obtained with a high radiochemical yield (99.3 ± 1.1%) and good stability (>48 h). The radiolabeled nanoemulsion showed an average droplet size of 24.7 nm, a polydispersity index of 0.21, a zeta potential of -45.3 mV, pH 7.4, an osmolality of 285.3 mOsm/kg, and viscosity of 1.24 mPa.s, indicating suitability for parenteral administration. In silico assessment suggested that the labeling did not affect the biological activity of gliclazide. The suggestion was further supported by the in vivo blocking study. Following intravenous administration of nanoemulsion, the pancreas uptake was highest in normal rats (19.57 ± 1.16 and 12 ± 0.13% ID) compared to diabetic rats (8.51 ± 0.16 and 5 ± 0.13% ID) at 1 and 4 h post-injection, respectively. All results supported the feasibility of radioiodinated gliclazide nanoemulsion as a tracer for pancreatic β-cells.

An Overview of In Vitro Assays of 64Cu-, 68Ga-, 125I-, and 99mTc-Labelled Radiopharmaceuticals Using Radiometric Counters in the Era of Radiotheranostics

Radionuclides are unstable isotopes that mainly emit alpha (α), beta (β) or gamma (γ) radiation through radiation decay. Therefore, they are used in the biomedical field to label biomolecules or drugs for diagnostic imaging applications, such as positron emission tomography (PET) and/or single-photon emission computed tomography (SPECT). A growing field of research is the development of new radiopharmaceuticals for use in cancer treatments. Preclinical studies are the gold standard for translational research. Specifically, in vitro radiopharmaceutical studies are based on the use of radiopharmaceuticals directly on cells. To date, radiometric β- and γ-counters are the only tools able to assess a preclinical in vitro assay with the aim of estimating uptake, retention, and release parameters, including time- and dose-dependent cytotoxicity and kinetic parameters. This review has been designed for researchers, such as biologists and biotechnologists, who would like to approach the radiobiology field and conduct in vitro assays for cellular radioactivity evaluations using radiometric counters. To demonstrate the importance of in vitro radiopharmaceutical assays using radiometric counters with a view to radiogenomics, many studies based on ⁶⁴Cu-, ⁶⁸Ga-, ¹²⁵I-, and ^99mTc-labeled radiopharmaceuticals have been revised and summarized in this manuscript.

Preparation and preliminary evaluation study of [131I]iodocolchicine-gallic-AuNPs: a potential scintigraphic agent for inflammation detection

BACKGROUND

Nanomedicine offers great potential for scintigraphic diagnostic imaging with lower risk and higher quality compared to other traditional techniques.

OBJECTIVES

This work aimed to develop and evaluate gold nanoparticles combined with gallic acid (gallic-AuNPs) and [¹³¹I]iodocolchicine as a scintigraphic probe for inflammation.

METHODS

[¹³¹I]iodocolchicine-gallic-AuNPs were synthesized via chemical reduction method where gallic acid was used as reducing agent and [¹³¹I]iodocolchicine was used as stabilizing agent. Then a characteristic profile for the synthesized nano-platform was performed including size analysis, zeta potential, radiochemical yield and in-vivo biodistribution in inflammation bearing mice.

RESULTS AND CONCLUSION

This platform was successfully synthesized with good stability, appropriate particle size (10 nm diameter for AuNPs), and high radiochemical purity for [¹³¹I]iodocolchicine (96.79%). The in-vivo study indicated that [¹³¹I]iodocolchicine-gallic-AuNPs accumulated with a high target to non-target ratio in intravenous injection and high retention value in intra-inflammation injection in inflammation model. The obtained data supported the usefulness of the new platform ([¹³¹I]iodocolchicine-gallic-AuNPs) as a tracer for the detection and localization of inflammation.