3D-printed particles improve drug delivery in inhalers

Inhaled medications are essential in treating respiratory diseases. Their effectiveness depends on how well the active ingredient detaches from carrier particles and reaches the lungs. Researchers at Kiel University have now produced carrier particles with defined geometries using advanced 3D printing, making it possible to study the direct impact of shape on drug delivery.

Using two-photon polymerization, a 3D printing technique with nanometer precision, the team created millions of identical particles. Thanks to a new method developed at Karlsruhe Institute of Technology (KIT), 49 structures can be printed at the same time, greatly accelerating production.

• Four different particle designs were tested.
• Over two million identical particles of each design were produced.
• One design was further tested with varying surface roughness levels.

The particles were then combined with a model drug, mimicking real inhaler formulations.

"For the drug to be effective, it has to detach from the carrier when inhaled and reach the lungs with the airflow," explains first author Melvin Wostry. "If it sticks, it is simply swallowed and never reaches its target."

Tests confirmed that particle geometry strongly influenced drug release.

• The Pharmacone design, with a star-like shape and multiple protruding tips, performed best.
• The fine particle fraction, the drug portion under five micrometers, was four times higher with this design compared to the next-best variant.
• Surface roughness, however, showed no significant effect.

Professor Regina Scherließ notes: "One shape we call ‘Pharmacone’ was the clear winner. Its star-like geometry features several protruding tips on the surface. The fine particle fraction – meaning the portion of the drug in the respirable range below five micrometers – was four times higher with this geometry than with the next-best design."

Currently, the printed carriers serve only as model particles for research, not for clinical use. Still, the findings open promising perspectives. In the future, biodegradable structures based on these designs could be integrated directly into dry powder inhalers.

"Our results show that modern technologies such as high-resolution 3D printing are opening entirely new avenues in pharmaceutical development," says Regina Scherließ. "We can now deliberately influence the behavior of medications through design – a kind of fine-tuning on the micrometer scale."

COMPAMED-tradefair.com; Source: Kiel University