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ISSN Druckformat: 1044-5110
ISSN Online: 1936-2684
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AN ATOMIZER TO GENERATE MONODISPERSE DROPLETS FROM HIGH VAPOR PRESSURE LIQUIDS
ABSTRAKT
This work describes an atomizer capable of generating monodisperse droplets of high vapor pressure liquids such as HFA227ea and HFA134a. This atomizer is expected to be a useful tool in future fundamental explorations of the mechanics of these highly dynamic aerosols. Hydrofluoroalkanes (HFAs) are the most common propellants in metered dose inhalers (MDIs), which are themselves the most common delivery method for pulmonary disease medications. As a result of the high vapor pressure of these fluids, generation of monodisperse droplets and their study are not possible with previously existing monodisperse atomizers due to fluid flashing when exposed to ambient conditions. The new atomizer uses a piezoelectric transducer to disintegrate the propellant jet, a cooling circuit with a low-temperature limit of −30°C to reduce propellant vapor pressure, and a high-pressure feed system (up to 2.7 MPa) to keep the propellant in the liquid phase, thereby avoiding flash atomization. In the current setup, the diameter of the generated droplets was monitored with a laser scattering system (using Fraunhofer diffraction theory) to optimize the operating parameters of the setup (for example, the actuation frequency and amplitude of the piezoelectric transducer). This monitoring system allowed for the measurement of droplet geometric diameter, spacing, and velocity. The capabilities of the atomizer for generating monodisperse droplets are demonstrated by a case study in which monodisperse dry particles of beclomethasone dipropionate (BDP) are generated using a solution of BDP, ethanol co-solvent, and HFA134a propellant.
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Ivey James W., Bhambri Pallavi, Church Tanya K., Lewis David A., McDermott Mark T., Elbayomy Shereen, Finlay Warren H., Vehring Reinhard, Humidity affects the morphology of particles emitted from beclomethasone dipropionate pressurized metered dose inhalers, International Journal of Pharmaceutics, 520, 1-2, 2017. Crossref
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Wang Hui, Bhambri Pallavi, Ivey James, Vehring Reinhard, Design and pharmaceutical applications of a low-flow-rate single-nozzle impactor, International Journal of Pharmaceutics, 533, 1, 2017. Crossref
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Ivey James W., Bhambri Pallavi, Church Tanya K., Lewis David A., Vehring Reinhard, Experimental investigations of particle formation from propellant and solvent droplets using a monodisperse spray dryer, Aerosol Science and Technology, 52, 6, 2018. Crossref
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Wang Hui, Nobes David S., Vehring Reinhard, Particle Surface Roughness Improves Colloidal Stability of Pressurized Pharmaceutical Suspensions, Pharmaceutical Research, 36, 3, 2019. Crossref
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Baldelli Alberto, Jeronimo Matthew, Tinney Matthew, Bartlett Karen, Real-time measurements of formaldehyde emissions in a gross anatomy laboratory, SN Applied Sciences, 2, 4, 2020. Crossref
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Taylor Judith A., McLoughlin Rory, Sandford John, Bevan Ruth, Aldred David, Legionella species: A potential problem associated with rain water harvesting systems?, Indoor and Built Environment, 30, 6, 2021. Crossref
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Baldelli Alberto, Ou Junfei, Barona David, Li Wen, Amirfazli A., Sprayable, Superhydrophobic, Electrically, and Thermally Conductive Coating, Advanced Materials Interfaces, 8, 2, 2021. Crossref
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Wang Zheng, Wang Hui, Vehring Reinhard, Leucine enhances the dispersibility of trehalose-containing spray-dried powders on exposure to a high-humidity environment, International Journal of Pharmaceutics, 601, 2021. Crossref
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Baldelli Alberto, Ou Junfei, Li Wen, Amirfazli Alidad, Spray-On Nanocomposite Coatings: Wettability and Conductivity, Langmuir, 36, 39, 2020. Crossref
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Baldelli Alberto, Wells Simon, Pratap-Singh Anubhav, Impact of Product Formulation on Spray-Dried Microencapsulated Zinc for Food Fortification, Food and Bioprocess Technology, 14, 12, 2021. Crossref
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Baldelli Alberto, Bschaden Ben, Amirfazli Alidad, Sameoto Dan, Reproducibility of superhydrophobic and oleophobic polymeric micro surface topographies, Surface Topography: Metrology and Properties, 8, 4, 2020. Crossref
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Wang Zheng, Ordoubadi Mani, Wang Hui, Vehring Reinhard, Morphology and formation of crystalline leucine microparticles from a co-solvent system using multi-orifice monodisperse spray drying, Aerosol Science and Technology, 55, 8, 2021. Crossref