Asthma inhalers could soon become more effective thanks to a clever new way of manufacturing the particles they deliver, developed by a team of Australian chemical engineers. Current puffer designs and typical size range of particles mean a large portion of the medication propelled into a patient's throat remains there. Only a fraction of each dose reaches the area of the lungs where it is effective in treating asthma symptoms. But Dr Meng Wai Woo, a lecturer in Monash University, Clayton, Australia, and his team have now developed a method of producing ultra-fine particles that will make drug delivery more consistent and efficient. The new method, known as antisolvent vapour precipitation, uses ethanol to dehydrate droplets and results in super-small particles of uniform size. "Ultrafine uniform particles will ensure that fewer drug particles get stuck in the throat while more can reach the lower regions of the lungs," said Dr Woo, who is a lecturer in Monash University's Department of Chemical Engineering. "Because we can now make the small particles more uniform, it means that the inhalers will work better." The team's work results in particles smaller than a micron (thousandth of a millimetre) in diameter, which is much smaller than those produced by conventional dehydrating mechanisms - these are limited by the size of the atomised droplet. The team's discovery was unveiled at the 18th International Drying Symposium in Xiamen, China, last year. It is likely to create interest among pharmaceutical companies. [login type="readmore"] IMPROVED EFFICIENCY It is estimated that 300 million people suffer from asthma symptoms worldwide. Infusion devices and metered dose inhalers account for around $US20 billion in worldwide sales each year, with the key development aim being to balance improved efficiency against the cost of manufacture. Dr Woo's method means that the pharmaceutical industry can now potentially deliver critical medicines via the airway direct into the lungs with much greater accuracy. "From a drug manufacturer's perspective, this new approach can maintain the uniformity of the particle and yet potentially maintain commercially viable production rate," according to Dr Woo. Investigations into using ethanol as a means of producing ultrafine particles began in 2011, as part of Dr Woo and his team's ongoing research into manufacturing processes in the dairy industry. While attempting to produce lactose crystals, his team decided to reject the traditional hot-air drying method and use nitrogen laced with ethanol vapour as an alternative dehydrating agent. To their surprise, the result was not the crystals that they had expected, but hundreds of very tiny, very uniform lactose particles. Further testing showed that the amount of alcohol that was absorbed into the initial droplets was a key variable in influencing the outcome. Assisted by a grant from the Australian Research Council, the research team is now testing its method on another dairy product, whey, and they are researching the ultrafine particle delivery of protein-based medicines. The team is also building a demonstration unit to showcase the anti-solvent vapour precipitation process, which will be completed later this year. Dr Meng Wai Woo completed his PhD (chemical engineering) in spray drying and computational fluid dynamics from the National University of Malaysia in 2010. Prior to embarking on a research career, he was a process engineer in the petrol chemical industry in Malaysia. Dr Woo now works as a lecturer in the Department of Chemical Engineering in Monash University, Australia. His specialisation is spray drying and making functional particles.