**5.2 Soft mist inhaler**

Soft mist inhaler (SMI) is a relatively new generation, propellant-free inhaler that delivers drugs to the lung more efficiently than pMDIs because of the lower spray velocity and longer duration time [66]. Carrigy et al. compared the delivery efficiency of phage among vibrating mesh nebulizer, jet nebulizer and SMI [14]. SMI was showed to deliver phage D29 at high titers quickly (~5 × 108 pfu/actuation) with an acceptable titer reduction (0.6 log pfu/ml) and a higher lung delivery (3.2 × 106 pfu/actuation of inhalable active phage). This compact and light weight device may act as an attractive option for self-administration of phage aerosols.
