Droplet and particle size distribution… Characterization of personal care aerosols can aid product development and reduce negative health effects. Mårten Svensson Ola Nerbrink Emmace Consulting AB & Respiron Consulting AB, Lund, Sweden Member of MVIC AB This paper was originally presented at the Aerosol Dispensing Forum in Paris, France. of the intended property of the product; it can also minimize unwanted lung deposition. These methods are used to characterize aerosol spray attributes such as the angle, pattern, droplet size, etc., along with the dosing and component concentration. Typical methodologies to access these are spray pattern and plume geometry, together with laser diffraction. Spray Pattern & Plume Geometry The spray pattern and plume geometry method consists of a high speed charge coupled device (CCD) camera and a light emitting source. The light is usually a laser emitting infrared (IR) light in a conical “fishtail” form. Data is captured as high speed pictures (typically 500 hertz Hz) of frontal (spray pattern) or sideways (geometry) projection. These pictures are pixelated and converted to numerical data using standard protocols in proprietary software installed on a computer. The set-up is shown in Figure 1 and Figure 2. These images will give the test administrator information on the aerosolization process versus time. He/she will get visual information on the evolving plume and attributes, such as the angle of the spray from the sideways view and its shape from the frontal view. This data can be used in the development process to observe trends and the influence of Personal care/cosmetic aerosol products produce both droplet aerosols and dry particle aerosols when activated and used. These aerosol products are in daily use by both end consumers and by professionals. The aerosol spray nozzle of these products generates and emits an aerosol cloud containing certain droplet/particle size distributions. Different product types and manufacturers will have different characteristics. Liquid droplets emitted from products will start to evaporate and shrink in size and will thereby potentially reach a size range that can be inhaled by the user. Inhalable aerosols can potentially penetrate into the lungs where they can deposit. There is a strong link between inhalation product development in the pharmaceutical industry (e.g. asthma inhalers) and aerosol product development in the personal care/cosmetics industry. In the pharmaceutical industry, frequent analysis of aerosol characteristics is performed to optimize drug delivery to a patient. In personal care cosmetic aerosol development, the requirements are the opposite—the aerosol should not be inhaled by the professional user or consumer. As a consequence, and as an opportunity, the methods used in pharmaceutical product development can aid the development of, for instance, spray nozzle optimization September 2016 Spray 41 Figure 1: Spray Pattern Set-Up Figure 2: Plume Geometry Set-Up
Spray September 2016
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