Development and evaluation of Dry Powder Inhalation Formulation of Remdesivir Nanosuspension by Spray Drying Technique

Introduction: Significant global health issues are caused by respiratory viral infections, such as COVID-19, which call for effective and focused drug delivery methods to improve treatment effectiveness and lessen systemic side effects. The broad-spectrum antiviral Remdesivir has demonstrated potential in treating these infections; however, it has low pulmonary access and poor aqueous solubility when administered by traditional methods. Antivirals can be directly and non-invasively delivered to the lungs, the main site of infection, using Dry Powder Inhaler Pulmonary Drug Delivery System. In order to optimise therapeutic advantages, reduce side effects, and increase local drug concentration, this study attempts to create a DPI formulation of Remdesivir. Objectives: The aim is to formulate and assess a spray-dried Remdesivir DPI for better bioavailability and pulmonary delivery. Materials and Methods: Remdesivir was formulated as a nanosuspension and then spray-dried into particles that could be inhaled in. The powder was comprehensively characterized using Fourier-Transform Infrared Spectroscopy, Scanning Electron Microscopy, X-ray Powder Diffraction, and Differential Scanning Calorimetry. Solubility enhancement, aerosolisation, and in vitro drug release were evaluated. Results: The particles had a fine particle percentage of 68.84±4% and a respirable size of 1-5 μm. Aerosolisation was enhanced by the rough, corrugated surfaces that were visible through SEM. Amorphous conversion was verified by DSC and XRPD, increasing solubility by 17-18 times. Within 150 min, more compared to 70% of the drug was released, and cascade impaction confirmed deep lung deposits. Conclusion: Remdesivir's modified DPI formulation showed improved solubility, effective lung targeting, and prolonged drug release, indicating a high potential for treating viral respiratory infections.