School of Pharmacy, Monash University Malaysia, Bandar Sunway, Selangor, Malaysia,
Nutrition Unit, Malaysian Palm Oil Board, Bandar Baru Bangi, Selangor, Malaysia,
Int J Nanomedicine. 2019 Feb 12;14:1101-1117. doi: 10.2147/IJN.S184912. eCollection 2019.
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 (Tc) will allow for the tracking of the nanocarrier noninvasively via nuclear imaging. The purpose of this study was to formulate, characterize, and optimize Tc-labeled niosomes.
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 H and C nuclear magnetic resonance spectroscopy). Niosomes were radiolabeled by surface chelation with reduced Tc. Parameters affecting the radiolabeling efficiency such as concentration of stannous chloride (SnCl·HO), 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.
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·HO 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. Tc-labeled niosomes exhibited high radiolabeling efficiency (>90%) and showed good in vitro stability for up to 8 hours.
To our knowledge, this is the first study published on the surface chelation of niosomes with Tc. The formulated Tc-labeled niosomes possessed high radiolabeling efficacy, good stability in vitro, and show good promise for potential use in nuclear imaging in the future.
尼森体是基于非离子表面活性剂的囊泡，具有某些独特的特性，使其成为癌症治疗中持续药物输送的理想纳米载体。生物分布研究对于评估纳米载体系统是否通过增强的通透性和保留效应在肿瘤中优先积累是至关重要的。放射性同位素如锝-99m（Tc）标记纳米载体将允许通过核成像无创跟踪纳米载体。本研究的目的是制备、表征和优化 Tc 标记的尼森体。
尼森体由山梨醇单硬脂酸酯 60、胆固醇和合成的 D-α-生育酚聚乙二醇 1000 琥珀酸二乙三胺五乙酸（通过 H 和 C 核磁共振波谱确认合成）的混合物制备。通过表面螯合还原的 Tc 对尼森体进行放射性标记。评估了影响放射性标记效率的参数，如氯化亚锡（SnCl·HO）的浓度、pH 值和孵育时间。在 37°C 的 0.9%生理盐水和人血清中研究了放射性标记的尼森体的体外稳定性，最长可达 8 小时。
尼森体的平均粒径为 110.2±0.7nm，多分散指数为 0.229±0.008，zeta 电位为-64.8±1.2mV。实验数据表明，30μg/mL 的 SnCl·HO 是放射性标记过程所需的最佳还原剂浓度。获得高放射性标记效率所需的 pH 值和孵育时间分别为 pH5 和 15 分钟。Tc 标记的尼森体表现出高放射性标记效率（>90%），在体外稳定长达 8 小时。
据我们所知，这是首次发表的关于 Tc 与尼森体的表面螯合的研究。所制备的 Tc 标记的尼森体具有高放射性标记效率、良好的体外稳定性，并有望在未来的核成像中得到应用。
