Daniel J Duke1, Alan L Kastengren2, Nicholas Mason-Smith3, Yang Chen4, Paul M Young4, Daniela Traini4, David Lewis5, Daniel Edgington-Mitchell3, Damon Honnery3. 1. Energy Systems Division, Argonne National Laboratory, Lemont, Illinois, USA. dduke@anl.gov. 2. X-ray Science Division, Argonne National Laboratory, Lemont, Illinois, USA. 3. Laboratory for Turbulence Research in Aerospace & Combustion, Department of Mechanical & Aerospace Engineering, Monash University, Melbourne, Victoria, Australia. 4. Respiratory Technology, Woolcock Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia. 5. Chiesi Limited, Chippenham, UK.
Abstract
PURPOSE: Drug concentration measurements in MDI sprays are typically performed using particle filtration or laser scattering. These techniques are ineffective in proximity to the nozzle, making it difficult to determine how factors such as nozzle design will affect the precipitation of co-solvent droplets in solution-based MDIs, and the final particle distribution. METHODS: In optical measurements, scattering from the constituents is difficult to separate. We present a novel technique to directly measure drug distribution. A focused x-ray beam was used to stimulate x-ray fluorescence from the bromine in a solution containing 85% HFA, 15% ethanol co-solvent, and 1 [Formula: see text] / [Formula: see text] IPBr. RESULTS: Instantaneous concentration measurements were obtained with 1 ms temporal resolution and 5 [Formula: see text] spatial resolution, providing information in a region that is inaccessible to many other diagnostics. The drug remains homogeneously mixed over time, but was found to be higher at the centerline than at the periphery. This may have implications for oropharyngeal deposition in vivo. CONCLUSIONS: Measurements in the dynamic, turbulent region of MDIs allow us to understand the physical links between formulation, inspiration, and geometry on final particle size and distribution. This will ultimately lead to a better understanding of how MDI design can be improved to enhance respirable fraction.
PURPOSE: Drug concentration measurements in MDI sprays are typically performed using particle filtration or laser scattering. These techniques are ineffective in proximity to the nozzle, making it difficult to determine how factors such as nozzle design will affect the precipitation of co-solvent droplets in solution-based MDIs, and the final particle distribution. METHODS: In optical measurements, scattering from the constituents is difficult to separate. We present a novel technique to directly measure drug distribution. A focused x-ray beam was used to stimulate x-ray fluorescence from the bromine in a solution containing 85% HFA, 15% ethanol co-solvent, and 1 [Formula: see text] / [Formula: see text] IPBr. RESULTS: Instantaneous concentration measurements were obtained with 1 ms temporal resolution and 5 [Formula: see text] spatial resolution, providing information in a region that is inaccessible to many other diagnostics. The drug remains homogeneously mixed over time, but was found to be higher at the centerline than at the periphery. This may have implications for oropharyngeal deposition in vivo. CONCLUSIONS: Measurements in the dynamic, turbulent region of MDIs allow us to understand the physical links between formulation, inspiration, and geometry on final particle size and distribution. This will ultimately lead to a better understanding of how MDI design can be improved to enhance respirable fraction.
Authors: Virgil A Marple; Daryl L Roberts; Francisco J Romay; Nicholas C Miller; Keith G Truman; Michiel Van Oort; Bo Olsson; Michael J Holroyd; Jolyon P Mitchell; Dieter Hochrainer Journal: J Aerosol Med Date: 2003
Authors: Nicolas A Buchmann; Daniel J Duke; Sayed A Shakiba; Daniel M Mitchell; Peter J Stewart; Daniela Traini; Paul M Young; David A Lewis; Julio Soria; Damon Honnery Journal: Pharm Res Date: 2014-06-17 Impact factor: 4.200
Authors: Nicholas Mason-Smith; Daniel J Duke; Alan L Kastengren; Peter J Stewart; Daniela Traini; Paul M Young; Yang Chen; David A Lewis; Julio Soria; Daniel Edgington-Mitchell; Damon Honnery Journal: Pharm Res Date: 2016-02-17 Impact factor: 4.200
Authors: Nicholas Mason-Smith; Daniel J Duke; Alan L Kastengren; Daniela Traini; Paul M Young; Yang Chen; David A Lewis; Daniel Edgington-Mitchell; Damon Honnery Journal: Pharm Res Date: 2017-01-17 Impact factor: 4.200