School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
J Control Release. 2010 Mar 3;142(2):187-95. doi: 10.1016/j.jconrel.2009.10.013. Epub 2009 Oct 17.
Microneedle patches coated with solid-state influenza vaccine have been developed to improve vaccine efficacy and patient coverage. However, dip coating microneedles with influenza vaccine can reduce antigen activity. In this study, we sought to determine the experimental factors and mechanistic pathways by which inactivated influenza vaccine can lose activity, as well as develop and assess improved microneedle coating formulations that protect the antigen from activity loss. After coating microneedles using a standard vaccine formulation, the stability of influenza vaccine was reduced to just 2%, as measured by hemagglutination activity. The presence of carboxymethylcellulose, which was added to increase viscosity of the coating formulation, was shown to contribute to vaccine activity loss. After screening a panel of candidate stabilizers, the addition of trehalose to the coating formulation was found to protect the antigen and retain 48-82% antigen activity for all three major strains of seasonal influenza: H1N1, H3N2 and B. Influenza vaccine coated in this way also exhibited thermal stability, such that activity loss was independent of temperature over the range of 4-37 degrees C for 24h. Dynamic light scattering measurements showed that antigen activity loss was associated with virus particle aggregation, and that stabilization using trehalose largely blocked this aggregation. Finally, microneedles using an optimized vaccine coating formulation were applied to the skin to vaccinate mice. Microneedle vaccination induced robust systemic and functional antibodies and provided complete protection against lethal challenge infection similar to conventional intramuscular injection. Overall, these results show that antigen activity loss during microneedle coating can be largely prevented through optimized formulation and that stabilized microneedle patches can be used for effective vaccination.
已经开发出了涂覆有固态流感疫苗的微针贴片，以提高疫苗的功效和患者的覆盖率。然而，用流感疫苗浸涂微针会降低抗原的活性。在这项研究中，我们试图确定使灭活流感疫苗失去活性的实验因素和机制途径，并开发和评估可保护抗原不失去活性的改良微针涂层配方。使用标准疫苗配方涂覆微针后，血凝活性测定表明流感疫苗的稳定性降低至仅 2%。添加羧甲基纤维素以增加涂层配方的粘度被证明会导致疫苗活性丧失。在筛选了一组候选稳定剂后，发现向涂层配方中添加海藻糖可保护抗原并保持三种主要季节性流感株（H1N1、H3N2 和 B）的抗原活性 48-82%。以这种方式涂覆的流感疫苗还表现出热稳定性，在 4-37°C 的温度范围内 24 小时内，其活性丧失与温度无关。动态光散射测量表明抗原活性丧失与病毒颗粒聚集有关，海藻糖的稳定作用在很大程度上阻止了这种聚集。最后，使用优化的疫苗涂层配方的微针被应用于皮肤以对小鼠进行疫苗接种。微针接种诱导了强大的系统和功能性抗体，并提供了针对致命性挑战感染的完全保护，与传统的肌肉内注射相似。总的来说，这些结果表明，通过优化配方可以在很大程度上防止微针涂层过程中抗原活性的丧失，并且稳定化的微针贴片可用于有效接种疫苗。
