Dry powder inhalers, commonly used for managing asthma, could be repurposed to treat reflux, if designed with the right particle size to target the throat, a new study suggests.
Laryngopharyngeal reflux (LPR) is a condition that affects the upper airway and causes persistent throat symptoms such as hoarseness, chronic cough, excess mucus and a sensation of something stuck in the throat. Unlike typical acid reflux, which affects the oesophagus, LPR causes irritation higher up, around the voice box and throat, where tissues are especially sensitive.
Doctors often prescribe proton pump inhibitors (PPIs) as a first-line treatment, but these medications may not work for everyone—especially when reflux affects the throat. This has led to growing interest in new treatment approaches that deliver medication more precisely to the affected area.
A new study published in the Journal of Aerosol Science has investigated whether dry powder inhalers (DPIs) – devices commonly used for asthma and other lung conditions – could be adapted to deliver drugs directly to the laryngopharynx. The research focused on understanding how factors like particle size, breathing technique and inhaler design influence how much medication reaches the throat.
What the study set out to do
The researchers, including Nikki Johnston at the Medical College of Wisconsin, used detailed computer simulations of the human airway to explore how medication particles travel during inhalation. Their goal was to identify the best way to deliver drugs to the laryngopharynx, the area of the throat often affected in LPR.
They tested:
- Different particle sizes (3 μm, 10 μm, and 50 μm)
- Variations in inhalation depth (shallow to forceful) and duration (short vs. long breaths)
- The effect of exit velocity, or how fast medication leaves the inhaler
By studying these factors, the researchers aimed to determine how both inhaler design and breathing style influence drug delivery. Getting more of the medication to the right place could improve symptom relief, reduce side effects and support better treatment outcomes for people with LPR.
The key finding
The standout result from the study was that particle size had the greatest impact on drug delivery to the throat.
- Particles measuring 10 micrometres (μm) delivered the highest dose to the laryngopharynx—around 20% of the emitted dose
- Smaller (3 μm) and larger (50 μm) particles were much less effective, delivering only 2 to 5%
- The researchers found that breathing style had little influence, which suggests that inhaler design plays a bigger role than how a patient uses it.
These findings highlight the importance of optimising inhaler particle size if the goal is to target reflux symptoms in the upper airway.
What this could mean for future treatments
Although the study didn’t evaluate any specific medications, its findings are relevant for future treatment strategies, particularly those aimed at conditions like LPR, where targeting the throat directly is key.
One area of interest is pepsin, a digestive enzyme linked to inflammation and tissue damage in the upper airway. As a test that detects pepsin in saliva, Peptest is closely following research like this, which may help pave the way for more effective delivery of pepsin-targeting therapies in the future.
Researchers will need to test these findings in real-world settings, but the study points clearly toward new possibilities. For people living with persistent throat symptoms, it’s a positive step toward more targeted and effective treatment options.
Peptest detects pepsin — the stomach enzyme that marks reflux — in a saliva sample. Collected at home, analysed in our UK laboratory, results back within 48 hours.
- Results in 48 hours
- No GP referral needed
- UK laboratory
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