<p>Characterization, optimization, and in vitro evaluation of Technetium-99m-labeled niosomes</p>

Abstract

Background and purpose Niosomes are nonionic surfactant-based vesicles that exhibit certain unique features which make them favorable nanocarriers for sustained drug delivery in cancer therapy. Biodistribution studies are critical in assessing if a nanocarrier system has preferential accumulation in a tumor by enhanced permeability and retention effect. Radiolabeling of nanocarriers with radioisotopes such as Technetium-99m ( 99m Tc) will allow for the tracking of the nanocarrier noninvasively via nuclear imaging. The purpose of this study was to formulate, characterize, and optimize 99m Tc-labeled niosomes. Methods Niosomes were prepared from a mixture of sorbitan monostearate 60, cholesterol, and synthesized D-α-tocopherol polyethylene glycol 1000 succinate-diethylenetriaminepentaacetic acid (synthesis confirmed by 1 H and 13 C nuclear magnetic resonance spectroscopy). Niosomes were radiolabeled by surface chelation with reduced 99m Tc. Parameters affecting the radiolabeling efficiency such as concentration of stannous chloride (SnCl 2 ·H 2 O), pH, and incubation time were evaluated. In vitro stability of radiolabeled niosomes was studied in 0.9% saline and human serum at 37°C for up to 8 hours. Results Niosomes had an average particle size of 110.2±0.7 nm, polydispersity index of 0.229±0.008, and zeta potential of −64.8±1.2 mV. Experimental data revealed that 30 µg/mL of SnCl 2 ·H 2 O was the optimal concentration of reducing agent required for the radiolabeling process. The pH and incubation time required to obtain high radiolabeling efficiency was pH 5 and 15 minutes, respectively. 99m Tc-labeled niosomes exhibited high radiolabeling efficiency (>90%) and showed good in vitro stability for up to 8 hours. Conclusion To our knowledge, this is the first study published on the surface chelation of niosomes with 99m Tc. The formulated 99m Tc-labeled niosomes possessed high radiolabeling efficacy, good stability in vitro, and show good promise for potential use in nuclear imaging in the future.

Simulation, In Vitro, and In Vivo Cytotoxicity Assessments of Methotrexate-Loaded pH-Responsive Nanocarriers

“…Span 60 and Tween 60 have some functional groups (OH, -ROH, ROR) that have a negative surface charge in water solution. Similar results were reported by Junyaprasert et al [ 71 ], Silva et al [ 72 ], Najlah et al [ 73 ], and many others. The EE% of drug delivery systems is a crucial metric for their effectiveness [ 22 ].…”

<p>Targeting cell cycle protein in gastric cancer with CDC20siRNA and anticancer drugs (doxorubicin and quercetin) co-loaded cationic PEGylated nanoniosomes</p>

“…The designed niosomes showed thermosensitivity, controlled drug release, improved passive targeting, drug stability, prolonged the circulation time, and increased drug concentration in tumor sites. Nanoniosomes have superiority to other kinds of drug delivery systems due to biocompatibilities, biodegradation, no allergic and toxic reactions, and low economic cost 11,12. In our previous study, we successfully prepared and optimized a cationic PEGylated niosome containing siRNA and drugs to combat the drug resistance and decrease the adverse effects 10.…”

Biodistribution Study of Niosomes in Tumor-Implanted BALB/C Mice Using Scintigraphic Imaging

“…TPGS-DTPA was synthesized and characterized following methods described previously (De Silva et al, 2019). Niosomes were prepared by simple sonication method as previously described by De Silva et al (2019).…”

“…Niosomes fabricated in the nanometer range has been proven to be able to encapsulate hydrophobic and hydrophilic compounds (Maniam et al, 2021). In our previous study, niosomes prepared with Span 60 were presented with high biocompatibility and stability in human serum (De Silva et al, 2019). That being said, some suggested that vesicle nanocarriers like liposomes may not release encapsulated compounds even if they are delivered to the tumors via EPR effect if the liposomes are too stable (Maeda, 2021).…”