SARS-CoV-2 inhibition in human airway epithelial cells using a mucoadhesive, amphiphilic chitosan that may serve as an anti-viral nasal spray

There are currently no cures for coronavirus infections, making the prevention of infections the only course open at the present time. The COVID-19 pandemic has been difficult to prevent, as the infection is spread by respiratory droplets and thus effective, scalable and safe preventive interventions are urgently needed. We hypothesise that preventing viral entry into mammalian nasal epithelial cells may be one way to limit the spread of COVID-19. Here we show that N-palmitoyl-N-monomethyl-N,N-dimethyl-N,N,N-trimethyl-6-O-glycolchitosan (GCPQ), a positively charged polymer that has been through an extensive Good Laboratory Practice toxicology screen, is able to reduce the infectivity of SARS-COV-2 in A549ACE2+ and Vero E6 cells with a log removal value of -3 to -4 at a concentration of 10 – 100 g/ mL (p < 0.05 compared to untreated controls) and to limit infectivity in human airway epithelial cells at a concentration of 500 g/ mL (p < 0.05 compared to untreated controls). GCPQ is currently being developed as a pharmaceutical excipient in nasal and ocular formulations. GCPQ’s electrostatic binding to the virus, preventing viral entry into the host cells, is the most likely mechanism of viral inhibition. Radiolabelled GCPQ studies in mice show that at a dose of 10 mg/ kg, GCPQ has a long residence time in mouse nares, with 13.1% of the injected dose identified from SPECT/CT in the nares, 24 hours after nasal dosing. With a no observed adverse effect level of 18 mg/ kg in rats, following a 28-day repeat dose study, clinical testing of this polymer, as a COVID-19 prophylactic is warranted.

目前尚无针对冠状病毒感染的治愈方法，因此预防感染成为当前唯一可行的途径。COVID-19大流行防控难度颇大，感染主要通过呼吸道飞沫传播，因此迫切需要有效、可扩展且安全的预防干预措施。本研究假设，防止病毒进入哺乳动物鼻腔上皮细胞可能是限制COVID-19传播的一种方法。本研究表明，N-棕榈酰-N-单甲基-N,N-二甲基-N,N,N-三甲基-6-O-甘油壳聚糖（GCPQ），一种经过广泛良好实验室实践毒理学筛选的带正电荷聚合物，能够在10-100微克/毫升的浓度下，对A549ACE2+和Vero E6细胞中的SARS-CoV-2感染性降低至对数清除值-3至-4（与未处理对照组相比，p < 0.05），并在500微克/毫升的浓度下限制人类气道上皮细胞的感染性（与未处理对照组相比，p < 0.05）。GCPQ目前正作为鼻用和眼用制剂的药物赋形剂进行开发。GCPQ通过静电结合病毒，防止病毒进入宿主细胞，可能是病毒抑制的最可能机制。放射性标记的GCPQ在小鼠中的研究显示，在10毫克/千克剂量下，GCPQ在小鼠鼻孔中的滞留时间较长，注射后24小时，13.1%的注射剂量在鼻孔的SPECT/CT扫描中被识别。在大鼠中，经过28天的重复剂量研究，观察到无不良反应的剂量为18毫克/千克，因此，将该聚合物作为COVID-19预防剂进行临床测试是必要的。