Respite nebulizer may replace inhalers and injections for drug delivery
Nebulizers aren't anything new – I remember using a big, bulky electric one 25 years ago to help my tiny three-year-old body breathe during asthma attacks. But a new prototype nebulizer developed at RMIT in Melbourne is designed to fit comfortably in your hand and deliver much higher doses of medicine per minute than current nebulizers. The researchers behind the device say it could replace inhalers and injections for people with conditions such as asthma, cancer, cystic fibrosis, and diabetes.
Traditional inhalers are problematic for people with weak or compromised lungs because using them requires a deep breath skilfully timed to coordinate with the squeezing action that releases the drug (which isn't easy at the best of times, but can be hellishly tricky if you're already struggling to breathe). They also tend to be of the one-size-fits-all persuasion, which means dosages can't be adjusted for a patient's age, gender, or disease severity, among other factors.
Worse, says lead researcher Leslie Yeo, "only 30 percent of the drugs actually get to the lungs. The rest is lost in the mouth." That's a lot of wasted money on medicine that doesn't reach its target.
Existing nebulizers aren't always a practicable alternative because they deliver their dosage very slowly, at around 0.4 mL/minute, and they can't be used for delivering insulin, proteins, peptides, or DNA (all of which some specialized medicines contain) because the mist they generate is too fine. But the prototype Respite device generates a slightly thicker, heavier mist that can carry these larger molecules directly to the lungs at a rate of up to 3 mL/min.
When trialed on sheep with a DNA flu vaccine, the nebulizer triggered comparable immune responses to an injection. This, the researchers hope, means that Respite could be used as a personalized, low-cost, direct-to-the-lungs delivery device for lung cancer drugs.
In the seven years since Yeo's team began work on Respite's predecessor, Respire, they have also tried the technology with other therapeutics, such as monoclonal antibodies for lung cancer and stem cells for lung regeneration. Yeo tells Gizmag that most of their work during this prototyping period has gone into "trying to better understand the science behind the phenomena by developing fundamental theories, with the hope that a better understanding will lead to improved designs [particularly in terms of delivery and efficiency]."
Respite works by generating surface acoustic waves (a type of sound wave that moves parallel to the surface of an elastic material, like a tiny earthquake) on a 2 cm by 1 cm microchip device. Those waves in turn agitate the liquid medicine in a small drug vial, converting it into an aerosol, or mist, that patients breath in through a mouthpiece on the end of the device.
Yeo tells Gizmag that the device currently requires several AA batteries for power, but they're working to miniaturize that for a future production version. Respite was showcased at TechInnovation 2015 in Singapore in September, where the researchers entered into talks with a number of potential commercial partners (Yeo says he cannot provide any details because of confidentiality agreements).
The researchers expect Respite to also have commercial applications in non-medical areas, such as cosmetics and surface/equipment sterilization. It's too soon to say what the final price will be, but Yeo hopes to get it out at below US$50 – and ideally with a version that's cheap enough for use with vaccines in developing countries, where diseases are sometimes spread through reuse of needles.
If all goes to plan, we may see the Respite nebulizer on the market in the next five years.
Source: RMIT University
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