A Southwest Research Institute (SwRI) project is developing techniques to improve inhalers for young children and other people who can't inhale deeply. The multidisciplinary team of researchers is creating a more effective inhaler for people who can't manage the strong, deep breath crucial for maximum benefit from standard inhalers. This work combines computational fluid dynamics (CFD), particle science, and pharmaceutical science to achieve improved designs. The internally funded project is a collaboration between three SwRI divisions: Mechanical Engineering, Powertrain Engineering, and Chemistry and Chemical Engineering.
For children and people with conditions like chronic obstructive pulmonary disease, or COPD, some inhalers don't reliably get enough medicine into the lungs. A lot of the medication remains in the mouth and throat or within the device instead of reaching deep in the airways. That wastes medicine and delivers an uncertain dosage."
Dr. Raouf Tajik, research engineer in SwRI's Mechanical Engineering Division and project's leader
To remedy this, SwRI is creating and testing new inhaler designs that reduce deposition in the mouth and throat, increase penetration of particles into the lungs, and allow weak inhalation from a young child or very sick person to pull enough medicine into the lungs.
Tajik led the CFD modeling, which simulated how air flows through a child's airway, and how particles from an inhaler deliver medication to the mouth, throat, and deeper airways.
SwRI Institute Engineer Dr. Imad Khalek oversees SwRI's Particle Science and Technology facility, which specializes in airborne particles. As part of SwRI's Powertrain Engineering Division, the facility normally studies particle emissions from automobile engines and batteries under fire. Khalek's team used a breathing simulator machine connected to a 3D-printed model of a child's airway to characterize the medicinal particles and pathways.
"We tested both dry and wet surface versions of the airway to mimic real, moist human airways," Khalek said. "This helped us to see that moisture changes how deeply inhaled particles penetrate."
Staff in SwRI's Chemistry and Chemical Engineering Division acted as subject matter experts for the particles and materials used in the inhaler. Dry powder inhalers use two components: a larger carrier particle and the much smaller drug particle. When particles are too small, users tend to exhale them. When they're too big, they often won't penetrate deeply into the lungs.
"The variability with inhalers can be significant and potentially dangerous: overdosing can lead to adverse effects while underdosing can make treatments ineffective," said SwRI Institute Scientist Dr. James Oxley, who leads the chemical engineering aspects of the project. "An improved design could deliver potentially more potent drugs that currently aren't suitable for inhalers because of that variability."
Cat training program benefits children with developmental disabilities