SwRI Researchers Design Better Inhalers for Young Children

Researchers at the Southwest Research Institute (SwRI) are developing inhaler technologies designed for young children and patients with chronic obstructive pulmonary disease (COPD) who cannot generate the deep, strong breath required by standard medical devices, according to project leader. Traditional inhalers often leave substantial medication trapped inside the device or deposited in the patient’s mouth and throat, resulting in wasted medicine and uncertain dosing, according to Dr. Raouf Tajik, a research engineer in SwRI’s Mechanical Engineering Division.

Computational Fluid Dynamics and Airway Modeling

To overcome the limitations of standard delivery systems, Tajik led computational fluid dynamics (CFD) modeling to simulate how air travels through a pediatric airway. The digital models track how medicinal particles travel from an inhaler device, mapping exact deposition rates in the mouth, throat, and deeper bronchial passages. By identifying where particles collide and stall, engineers can alter the internal geometry of the inhaler to ease the burden on patients with limited lung capacity.

Breathing Simulator Testing in Particle Science

Physical testing complements the digital modeling through work at SwRI's Particle Science and Technology facility, which is overseen by Institute Engineer Dr. Imad Khalek. Khalek's team connected a breathing simulator machine to a 3D-printed replica of a child's airway.

Chemical Engineering and Particle Formulation

Material optimization plays a critical role in dry powder inhaler performance, requiring a precise balance between carrier particles and active drug molecules. Dry powder systems rely on a larger carrier particle attached to a much smaller drug particle. If particles are too small, patients tend to exhale them immediately; if they are too large, they fail to reach the deep airways, according to SwRI Institute Scientist Dr. James Oxley, who leads the chemical engineering aspects of the project.

“The variability with inhalers can be significant and potentially dangerous: overdosing can lead to adverse effects while underdosing can make treatments ineffective,” Oxley said. He noted that improved designs could eventually deliver potent drugs that are currently considered unsuitable for inhalation therapy due to high dosing variability.

Multidisciplinary Collaboration for Future Device Design

The internally funded initiative brings together three distinct SwRI divisions: Mechanical Engineering, Powertrain Engineering, and Chemistry and Chemical Engineering. By merging fluid dynamics, emissions-grade particle testing, and chemical formulation, the multidisciplinary team aims to produce inhalers that require minimal inhalation force while maximizing targeted drug delivery to vulnerable patient populations.

Frequently Asked Questions

Why do standard inhalers fail some young children and patients with COPD?

Standard inhalers require a strong, deep breath for maximum benefit. Patients with limited lung capacity often cannot inhale deeply enough, causing medication to remain trapped in the device or deposit in the mouth and throat rather than reaching the lungs.

What role does computational fluid dynamics play in improving inhalers?

According to Dr. Raouf Tajik, CFD modeling simulates air movement through pediatric airways and tracks how particles deliver medication, allowing engineers to design devices that reduce mouth and throat deposition.

How do moisture and particle size affect medication delivery?

Testing with moist, 3D-printed airway models shows that moisture alters particle penetration depth. Additionally, particles must be sized precisely: oversized particles fail to reach deep airways, while undersized particles are often exhaled by the user.

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