Cross purposes Medspray’s nozzle technology has been flying under the radar for a long time—since the start of the company in 2002 until recent publications and its introduction at the CPhI pharmaceutical trade fair in 2015, where two different inhalers using the nozzle technology were launched. Since CPhI 2015, the nozzle technology has also caught the attention of the cosmetics industry. Apparently, the requirements of a spray for the pharmaceutical industry also apply for the cosmetics industry: a soft spray, long actuation time (multiple seconds), narrow particle size distribution and tunable spray cone. There are also major differences, of course; the spray for an inhaler must have small particles so as to be delivered in the lungs of a patient, whereas skin sprays for cosmetics or fragrances should preferably not be inhaled at all. However, both the pharma field and the cosmetic field seem to benefit from a narrow sized distribution and a slow moving, long lasting spray. The fact that Medspray can create a spray that gives a dry sensation on the skin when sprayed seems to be a unique selling point. The flow rate (and hence the duration of the spray with a given pump), the cone angle and the particle size distribution all can be tuned by engineering the geometric design of the spray nozzles. This is something that the cosmetic industry is not used to; current swirl nozzles used in cosmetics can’t be easily tuned to those aspects. Medspray is based in Enschede, the Netherlands. The nanotechnology-based spray nozzles are made from silicon, just like computer chips, although at Medspray no electronics are involved; the nozzle is a simple mechanical structure, an array of tiny holes in a thin membrane. The name Medspray stands for “medical sprays” and the company is currently going through the transformation from R&D towards manufacturing and supply for inhaler nozzles. The current EU Good Manufacturing Practice (GMP) Grade C clean room assembly facility, now mainly supplying nozzles for clinical trials with the inhalers, will be vastly expanded to produce multiple millions of nozzles for pharmaceutical inhalers in the coming years. Since processed silicon wafers are quite expensive, Medspray has, over the years, miniaturized the nozzle chips. Until 2005, the size was 4x4mm (0.15748" x 0.15748") with a glass packaging layer for strength. From 2006 to 2015, the size was 4x1mm (0.15748" x 0.0393701"), but quite recently Medspray has switched to a format of approximately 1x1mm (0.0393701"x 0.0393701"), so over 16 times more nozzle chips can be produced from the same wafer. One wafer can now hold chips for approximately 7,500 spray nozzle units. The patented assembly process uses no glues or sealants. By placing and welding the nozzle chips into their plastic holders, a robust spray nozzle unit is created. The spray pores on the nozzle chip are extremely small, between 1.5 and 25 microns in size. In comparison, a human hair has a diameter of 70 microns. The pores are made by etching processes based on lithographic masking techniques found in the computer industry. Compared to the sizes of features on current cell phone processor chips, the structures on the Medspray nozzle chips are quite large. The accuracy of these semiconductor technology-based spray nozzle chips is impressive. Tolerances are much smaller than for any mechanical processes, such as laser drilling, and all spray pores on a complete wafer are made in a single etching process, making this an economically interesting option for cosmetic applications, also. How pharma inhaler nozzles can create benefits for personal care & cosmetic sprays This paper was originally presented at both the New York and Paris Aerosol & Dispensing Forums. Anne Mechteld Mosman, Account Manager & Wilbur de Kruijf, Inhaler & Eye Spray Development, Medspray BV The Medspray Nozzle at 3 x 2.5mm Each jet can have its own direction. March 2017 Spray 29
Spray March 2017
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