Breathe Easy: Redesigning Inhalers for Asthma Patients

Asthma – a chronic lung disease that temporarily inflames and narrows the oxygen-carrying airways – is a common illness that affects 235 million people worldwide. Pressurized metered-dose inhalers are the most common method of drug delivery for asthma treatments, but require synchronized actuation of the inhaler with inhalation. Studies report that up to 92% of patients misuse their inhaler. Even with proper technique, only 10-20% of their medicine enters their lungs, depositing the rest in the upper airway system. As a result, $5-7 billion are lost each year in inhaler manufacturing and medicine production. To engineer a more efficient inhaler, preliminary tests were conducted with four different commercial inhalers. Each inhaler was tested in a respiratory tract model using proper technique and improper technique and then photographed. Using photo enhancement in GIMP, their two spray angles and average deposition were calculated. Based on the results, an inhaler bottom and six unique attachments – two mouth and four base parts – were modeled in SolidWorks and then 3D printed. The same tests were conducted on the eight different possible combinations. The best-performing prototype showed 54% less deposition than the best models on the market, warranting further tests and future implementation in a clinical setting.