Saha Tushar, Sinha Shubhra, Harfoot Rhodri, Quiñones-Mateu Miguel E, Das Shyamal C
School of Pharmacy, University of Otago, Dunedin 9054, New Zealand.
Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand.
Pharmaceutics. 2022 Jul 8;14(7):1432. doi: 10.3390/pharmaceutics14071432.
SARS-CoV-2, the causative agent of COVID-19, predominantly affects the respiratory tract. As a consequence, it seems intuitive to develop antiviral agents capable of targeting the virus right on its main anatomical site of replication. Ivermectin, a U.S. FDA-approved anti-parasitic drug, was originally shown to inhibit SARS-CoV-2 replication in vitro, albeit at relatively high concentrations, which is difficult to achieve in the lung. In this study, we tested the spray-drying conditions to develop an inhalable dry powder formulation that could ensure sufficient antiviral drug concentrations, which are difficult to achieve in the lungs based on the oral dosage used in clinical trials. Here, by using ivermectin as a proof-of-concept, we evaluated spray-drying conditions that could lead to the development of antivirals in an inhalable dry powder formulation, which could then be used to ensure sufficient drug concentrations in the lung. Thus, we used ivermectin in proof-of-principle experiments to evaluate our system, including physical characterization and in vitro aerosolization of prepared dry powder. The ivermectin dry powder was prepared with a mini spray-dryer (Buchi B-290), using a 23 factorial design and manipulating spray-drying conditions such as feed concentration (0.2% w/v and 0.8% w/v), inlet temperature (80 °C and 100 °C) and presence/absence of L-leucine (0% and 10%). The prepared dry powder was in the size range of 1−5 μm and amorphous in nature with wrinkle morphology. We observed a higher fine particle fraction (82.5 ± 1.4%) in high feed concentration (0.8% w/v), high inlet temperature (100 °C) and the presence of L-leucine (10% w/w). The stability study conducted for 28 days confirmed that the spray-dried powder was stable at 25 ± 2 °C/<15% RH and 25 ± 2 °C/ 53% RH. Interestingly, the ivermectin dry powder formulation inhibited SARS-CoV-2 replication in vitro with a potency similar to ivermectin solution (EC50 values of 15.8 µM and 14.1 µM, respectively), with a comparable cell toxicity profile in Calu-3 cells. In summary, we were able to manipulate the spray-drying conditions to develop an effective ivermectin inhalable dry powder. Ongoing studies based on this system will allow the development of novel formulations based on single or combinations of drugs that could be used to inhibit SARS-CoV-2 replication in the respiratory tract.
严重急性呼吸综合征冠状病毒2（SARS-CoV-2）是冠状病毒病（COVID-19）的病原体，主要影响呼吸道。因此，开发能够在病毒主要复制解剖部位靶向作用的抗病毒药物似乎是合乎常理的。伊维菌素是一种经美国食品药品监督管理局（FDA）批准的抗寄生虫药物，最初显示在体外能抑制SARS-CoV-2复制，尽管所需浓度相对较高，而在肺部难以达到这一浓度。在本研究中，我们测试了喷雾干燥条件，以开发一种可吸入干粉制剂，该制剂能够确保达到足够的抗病毒药物浓度，而基于临床试验中使用的口服剂量在肺部难以实现这一浓度。在此，以伊维菌素作为概念验证，我们评估了喷雾干燥条件，这些条件可促成开发出一种可吸入干粉制剂形式的抗病毒药物，进而可用于确保肺部有足够的药物浓度。因此，我们在原理验证实验中使用伊维菌素评估我们的系统，包括对制备的干粉进行物理表征和体外雾化。伊维菌素干粉使用小型喷雾干燥器（Buchi B-290）制备，采用23析因设计并控制喷雾干燥条件，如进料浓度（0.2% w/v和0.8% w/v）、进口温度（80℃和100℃）以及L-亮氨酸的有无（0%和10%）。制备的干粉粒径范围为1 - 5μm，本质上为无定形，具有皱纹形态。我们观察到在高进料浓度（0.8% w/v）、高进口温度（100℃）以及存在L-亮氨酸（10% w/w）的情况下，细颗粒分数较高（82.5±1.4%）。进行的为期28天的稳定性研究证实，喷雾干燥粉末在25±2℃/<15%相对湿度（RH）和25±2℃/53% RH条件下是稳定的。有趣的是，伊维菌素干粉制剂在体外抑制SARS-CoV-2复制的效力与伊维菌素溶液相似（EC50值分别为15.8μM和14.1μM），在Calu-3细胞中的细胞毒性特征相当。总之，我们能够控制喷雾干燥条件来开发一种有效的可吸入伊维菌素干粉。基于该系统正在进行的研究将促成开发基于单一药物或药物组合的新型制剂，可用于抑制呼吸道中的SARS-CoV-2复制。
