Copelli D, Bodria A, Magnani I, Militerno G, Ponticelli M, Usberti F and Leardi R
During the development of a new Pressurized Metered Dose Inhalers (pMDI) one of the key aspect is to achieve the right performances of the emitted aerosol. Among all variables that can impact the performances, the configuration of the actuator largely affects the atomization process and, as a consequence, the pMDI performances. In order to understand the effect of actuator orifice diameter and actuator sump volume on the final performance, a Face Centered Design has been applied. For each experiment fifteen responses were measured, using a Unit Spray Collector Apparatus (USCA) for the Delivered/Metered Dose and a Next Generation Impactor (NGI) for the Aerodynamic Particle Size Distribution tests. A Principal Component Analysis showed that the NGI responses can be used to demonstrate how the two variables affect the performance of the actuators, while the USCA responses are useless for this purpose. The effect of orifice diameter and sump volume on Fine Particle Mass, Fine Particle Fraction and Mass Median Aerodynamic Diameter, three relevant Aerodynamic Particle Size Distribution responses, were then quantitatively evaluated by Multiple Linear Regression.