In vitro evaluation of aerosol delivery of aztreonam lysine (azli): an adult mechanical ventilation model

<b>Background</b>: The delivery profile of Aztreonam lysine (AZLI) during mechanical ventilation (MV) is unknown. We evaluated the amount of AZLI drug delivered using an <i>in vitro</i> model of adult MV. <b>Methods</b>: An adult lung model designed to mimic current clinical practice was used. Both nebulizers were placed before a Y-piece and 4 settings were tested: A) Aeroneb solo® [AS] with a t-piece; B) AS with the spacer; C) M-Neb® [MN] with a t-piece and D) MN with the spacer. Performance was evaluated in terms of: 1) Mass median aerodynamic diameter (MMAD); 2) Geometric standard deviation (GSD), 3) Fine particle dose (FPD), 4) Fine particle fraction (FPF), 5) Inhalable mass (IM), and 6) Recovery rate (RR). <b>Results</b>: Both devices showed an adequate delivery of AZLI during MV, with MMAD between 2.4-2.5 µm and 87% of FPF. The FPD (38.8 and 31.7), IM (44.8 and 36.1) and RR (30 and 24) were similar for AS and MN respectively. Nebulizer aerosol delivery increased (50% and 70% respectively) for both nebulizers when using the spacer. <b>Conclusion</b>: Both AS and MN showed a good aerosol delivery profile for AZLI during <i>in vitro</i> mechanical ventilation. Better aerosol delivery performance was obtained using the spacer.