One of the strategies proposed for the neutralization of SARS-CoV-2 has been to synthetize small proteins able to act as a decoy towards the virus spike protein, preventing it from entering the host cells. In this work, the incorporation of one of these proteins, LCB1, within a spray-dried formulation for inhalation was investigated. A design of experiments approach was applied to investigate the optimal condition for the manufacturing of an inhalable powder. The lead formulation, containing 6% w/w of LCB1 as well as trehalose and L-leucine as excipients, preserved the physical stability of the protein and its ability to neutralize the virus. In addition, the powder had a fine particle fraction of 58.6% and a very high extra-fine particle fraction (31.3%) which could allow a peripheral deposition in the lung. The in vivo administration of the LCB1 inhalation powder showed no significant difference in the pharmacokinetic from the liquid formulation, indicating the rapid dissolution of the microparticles and the protein capability to translocate into the plasma. Moreover, LCB1 in plasma samples still maintained the ability to neutralize the virus. In conclusion, the optimized spray drying conditions allowed to obtain an inhalation powder able to preserve the protein biological activity, rendering it suitable for a systemic prevention of the viral infection via pulmonary administration.