Moraes BarbraKatyúscya Sanches, Vieira Simone Machado, Salgueiro Willian Goulart, Michels Luana Roberta, Colomé Letícia Marques, Avila Daiana Silva, Haas Sandra Elisa
J Nanosci Nanotechnol. 2016 Feb;16(2):1257-64. doi: 10.1166/jnn.2016.11668.
The aim of this work was to develop and characterize clozapine loaded polysorbate-coated polymeric nanocapsules and assess their toxicity in Caenorhabditis elegans, an invertebrate animal model. Formulations were prepared by nanoprecipitation method and characterized by particle size, zeta potential, pH, drug loading, entrapment efficiency and in vitro drug release. All nanocapsules prepared presented diameter around 140 nm, pH slightly acid and negative zeta potential. In vitro studies showed biphasic drug release from nanocapsules with decreasing of the release rate on nanoencapsulation. The t(1/2)beta of clozapine was 7.23 +/- 0.73 and 2.23 +/- 0.97 h for nanoencapsulated and free drug, respectively (p < 0.05), in pH 1.2 medium. Similar results were obtained in pH 6.8 buffer. Regarding toxicity evaluation, worms exposed to clozapine-loaded nanocapsules did not show the same mortality rate compared to others formulations, as the survival was significantly higher than the free drug treated-group. In addition, we observed that free clozapine decreased egg laying at the first reproductive day, whereas nanoencapsulated clozapine did not depict significant change of this parameter. Longevity assay showed no significant difference, demonstrating that the toxicological effects of clozapine observed in C. elegans are acute. In addition, we proved that free and nanoencapsulated clozapine were orally uptake by the worms, as determined by fluorescein-labeled nanocapsules. Then, the use of nanocapsules delayed the drug release and minimized the toxic effects of clozapine in worms, which can be used as a new animal model to evaluate the nanotoxicity of drug delivery systems.
本研究的目的是开发并表征负载氯氮平的聚山梨酯包衣聚合物纳米胶囊，并评估其在无脊椎动物模型秀丽隐杆线虫中的毒性。通过纳米沉淀法制备制剂，并通过粒径、zeta电位、pH值、载药量、包封率和体外药物释放进行表征。制备的所有纳米胶囊直径均约为140nm，pH值呈微酸性，zeta电位为负。体外研究表明，纳米胶囊呈现双相药物释放，纳米包封后释放速率降低。在pH 1.2介质中，纳米包封氯氮平和游离氯氮平的t(1/2)β分别为7.23±0.73小时和2.23±0.97小时（p<0.05）。在pH 6.8缓冲液中也获得了类似结果。关于毒性评估，与其他制剂相比，暴露于负载氯氮平纳米胶囊的线虫死亡率不同，其存活率显著高于游离药物治疗组。此外，我们观察到游离氯氮平在第一个生殖日会降低产卵量，而纳米包封氯氮平对此参数没有显著变化。寿命试验显示无显著差异，表明在秀丽隐杆线虫中观察到的氯氮平毒理学效应是急性的。此外，通过荧光素标记的纳米胶囊测定，我们证明游离和纳米包封的氯氮平均可被线虫口服摄取。因此，纳米胶囊的使用延迟了药物释放，并将氯氮平对线虫的毒性作用降至最低，这可作为评估药物递送系统纳米毒性的新动物模型。
