Purpose <p>Intranasal delivery of monoclonal antibodies (mAb) offers an attractive approach for preventing or treating respiratory viral infections. Previously, we showed that thin-film freeze-dried powder (TFFD powder) of AUG-3387, an anti-SARS-CoV-2 spike protein mAb, could be sprayed into the posterior nasal cavity region of a nasal cast model using Aptar’s unidose powder (UDSp) nasal spray system. This work investigated the feasibility of filling TFFD mAb powders into the UDSp system using drum filling.</p> Methods <p>New TFFD AUG-3387 powders were prepared by including magnesium stearate and/or hydroxypropyl methylcellulose in them. The powders were comminuted and their flow properties measured. A selected powder was filled into UDSp systems using a Harro Höfliger Drum TT benchtop filler or a Quantos hand-held powder dispenser at target fill weights of 0.5 and 1.0&#xa0;mg, and the performance of the filled systems was evaluated.</p> Results <p>The F8 TFFD AUG-3387 powder was selected for drum filling due to its ‘passable’ to ‘excellent’ flowability and its minimal sensitivity to controlled moisture exposure. Drum filling succeeded at both target fill weights, consistently compacting the powder into pucks without ejection failures. The average fill weight was 0.54 ± 0.09&#xa0;mg for the 0.5&#xa0;mg target and 1.11 ± 0.08&#xa0;mg for the 1.0&#xa0;mg target. The drum-filled UDSp systems performed similarly to the Quantos-filled systems in shot weight uniformity, emitted particle size, and deposition in a nasal cast, although differences were observed in certain spray characteristics.</p> Conclusions <p>It is feasible to drum fill TFFD mAb powder at low fill weights.</p> Graphical Abstract <p></p>