The small nozzle pores still have a relatively low flow resistance because the silicon nozzle plates are locally thinned to below one micron. Despite these thin membranes, the nozzle units can withstand very high operating pressures, while the necessary operating pressure is kept low. Simple existing “engines” can be used, such as trigger sprayers, finger spray pumps or compressed air aerosol cans. The flow rate of the nozzle chip can be determined by the number of pores—one, 10, 100, 200—or whatever is needed for the application. Each pore can be meticulously placed on the surface of the nozzle chip and each liquid jet from each single pore can be designed with its own vector. The jet coming out of each pore breaks up in primary droplets, which are two times the size of the spray pore as the British Lord Rayleigh discovered in 1870, on a bit larger scale. Two micron pores create four micron primary droplets. Twenty micron pores create 40 micron droplets. By engineering the size of the pores, their geometric pattern and their vectors, this enables Medspray to tailor the spray and to create any custom spray pattern. Hollow cones, massive cones, elliptical shapes and even square spray patterns can be achieved if the application requires it. For inhalation drugs, such as those needed to treat asthma or chronic obstructive pulmonary disease (COPD), the current “holy grail” is to replace the current pressurized metered dose inhalers (pMDIs) that use liquid hydrofluoroalkane (HFA) propellants, which have a high global warming potential. With the Medspray nozzle technology, it becomes feasible to create a fine, inhalable mist without the need for a fast evaporating propellant or excipient. A simple pump with a water-based formulation can be used. The inhalation spray comes out over a long period (e.g. two seconds) and at a low velocity. Compared to current inhaler devices, where the drug load comes out of the pMDI in two-tenths of a second, this is a big benefit. A gentler aerosol cloud means that less medication is lost in the mouth and throat and more medication reaches the patient’s lungs. This makes Medspray inhalers up to four times more efficacious than existing pMDIs. This also means asthma drug dosage can be lowered for the same therapeutic effect, leading to fewer side effects such as headaches and a high heart rate. Personal care applications Medspray’s first impressions of the current cosmetic spray field show potential of a similar benefit. If no evaporating liquid propellants or alcohol are used in the formulation then the current swirl nozzles used make a pretty wet cloud. For example, refreshing mineral water facial sprays generally come in large aerosol spray cans using compressed air with a swirl nozzle in the actuator head. At the start of the can, the spray pressure is around 10bar and the aerosol quality is wet, yet acceptable. Near exhaustion of the product, the pressure has dropped below 5bar or even below 3bar and the performance of the product is diminished. With Medspray’s nozzles, based on the Rayleigh spray principle, the diminishing operating pressure influences the flow rate, but not the droplet size, maintaining a nice, dry cloud, even near completion of the can. Eye care: The Medspray nozzles create a gentle, soft mist that can comfortably be sprayed on the bare eye Plain orifice nozzle. The droplet diameter = 2 x the jet diameter. The Medspray Nozzle with extremely fine mist. Perfume spray applications For perfume sprays, where finger pumps seem to dominate the field, the Medspray nozzles can help reduce or eliminate the ethanol content. Water-based perfumes can now be developed, because with the nozzle technology these sprays will no longer feel too wet to users. The spray cone can be tailored to be wider for body sprays and narrower for fine fragrances. The spray time of a finger pump can be tailored as well, from 0.5 seconds to three seconds, depending on what is desired. Spray 30 Spray March 2017
Spray March 2017
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