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Measurements and method parameters Spray pattern measurements were performed using a SprayVIEW ® system (Proveris Scientific, Marlborough MA, US). is non-impaction measurement system uses a laser light sheet and high-speed digital camera to collect images. Viota ® software (Proveris Scientific) was used to quantify the time-averaged composite image for spray pattern at 30 mm distance from the edge of the orifice. Spray pattern measurements are visualized as the cross-sectional area perpendicular to the axis of the spray. (Figure 2) Key measurements include D max and D min (maximum and minimum diameter through center of gravity), ovality and area, averaged over time or assessed at individual time points. For each product, ten spray pattern measurements were taken from each canister for each of the eight sump design components. ree canisters from each product were tested. Area and ovality spray pattern results were evaluated. Identical shaking and actuation parameters (shake duration/angle, actuation velocity/acceleration, hold time) were used throughout the study. These parameters were derived from an ergonomic study to be consistent with average patient usage of these products. e laser and camera settings were also kept identical for all canisters from each product. All data were statis- tically analyzed using JMP ® software (SAS Institute, Inc., Cary, NC, US). Spray pattern area throughout the life of the canister was evaluated for both ProAir and Ventolin to ensure consis- tency through actuations. e data showed that, with consistent shaking and spray interval conditions, there were no large fluctuations in spray pattern area through- out the lives of the canisters (ProAir relative standard deviation (RSD) = 7.68%; Ventolin RSD = 12.02%). Results and discussion Device component design effects on spray pattern area Spray pattern is sensitive to the way devices are actuated (stroke length, hold time, actuation velocity), formula- tion properties, actuator design and pump/valve selec- tion. 6 e following experiments look at pMDI spray performance differences in formulations and actuator sump design. Results of comparisons between ProAir and Vento- lin. ProAir and Ventolin contain the same active phar- maceutical ingredient (API) of albuterol sulfate, how- ever, they have different formulations (API + propellant + excipients). e left side of Figure 3 illustrates the vari- ability of the combined results from all eight sumps. Formulation and/or metering valve can impact spray pattern area results, as Ventolin had greater variability (standard deviation (SD) = 19.88) compared to ProAir (SD = 13.33). Despite the formulation differences, both products show similar trends in spray pattern area across all eight sump components (see the trend lines through the mean spray pattern area on the right side of Figure 3). Sump ID# Orifice Diameter (mm) Orifice Length (mm) Chamber Depth (mm) 1 0.25 0.7 7.55 2 0.31 0.7 7.55 3 0.25 0.9 7.55 4 0.31 0.9 7.55 5 0.25 0.7 8.15 6 0.31 0.7 8.15 7 0.25 0.9 8.15 8 0.31 0.9 8.15 Table 1 Actuator sump design features; three parameter factors at two levels. 2 Figure 1 Diagrams of the sump component, its details and design parameters. Ø Orifice Diameter Orifice Jet Length Expansion Chamber or Sump Depth Figure 2 Representative spray pattern measurements from a SprayVIEW ® system. The image highlights a typical spray pattern from a pressurized metered dose inhaler (pMDI). Inhalation OctOber 2017 21