Mixing drugs and alcohol? That might be a no-no but breathe easy. It seems just right when it comes to designing the better asthma inhaler.
A Monash University research team led by Dr Meng Wai Woo hit upon the novel medical cocktail to address an age-old problem of efficiently delivering asthma drugs. Even the best asthma inhalers – with metered doses – don’t do their job particularly well. Typically, only a fraction of the stuff you inhale goes into the needy lungs. Most of it simply lingers in the throat as an aftertaste.
Ultrafine particles the key
Woo and his team have redressed the problem. They used a new method, called anti-solvent vapour precipitation, to break down the medication into ultrafine particles and added ethanol to dehydrate the droplets, resulting in super-small particles of uniform size. The particles are smaller than a micron (thousandth of a millimetre) in diameter – much smaller than those produced by conventional dehydrating mechanisms.
“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 Woo. “Because we can now make the small particles more uniform, it means the inhalers will work better.”
From a drug manufacturer’s perspective, this new approach can maintain the uniformity of the particle and yet potentially maintain commercially viable production rate, he added.
A happy accidental discovery
The team’s discovery, unveiled at the 18th International Drying Symposium in Xiamen, China, last year, came from research in an entirely different field – the dairy industry’s manufacturing process. In a bid to produce lactose crystals, Woo’s team rejected traditional hot air drying and instead used nitrogen laced with ethanol vapour as an alternative dehydrating agent.
To their surprise, the result was not the crystals they expected, but the very opposite – hundreds of very tiny, very uniform lactose particles. Woo used further tests then and determined that the amount of alcohol absorbed into the initial droplets was key to securing the ultra-fine particles.
Armed with a grant from the Australian Research Council, the Monash team is now testing the same method on another dairy product – whey – to see if it can be used to deliver similar ultrafine particles of protein-based medicines.
Woo is one of 12 early-career scientists supported by Fresh Science, a national program sponsored by the Australian Government that helps unveiling groundbreaking research to the public. Fresh Science program, established in 1998, is also backed by Museum Victoria and CSL.