A significant advantage of the PRINT method is that it consistently yields uniform populations of particles. "There's essentially no dispersion in size and shape. That's not been available before," says DeSimone.

The technology also lets formulators create particle sizes and shapes that traditional methods have not generated successfully in the past. For example, DeSimone's team has made cylindrical particles that are 80 nm in diameter, and they can achieve particle sizes as large as 5 µm. The team is also using PRINT to develop particles that can rotate automatically in a low-velocity airstream, much like a maple seed does when it falls from a tree. "We're getting into characteristics that have never been designed into a respiratory drug therapy," says DeSimone.

It's hard to achieve this kind of mixture through traditional particle approaches, such as spray drying from a solution, because ingredients in various phases tend to separate, and the processes give operators little latitude for controlling the ratio of matrix to drug. "With PRINT, we can precisely tailor the ratio of those two components because we're simply filling a cup," says DeSimone. The high level of control that PRINT offers could help manufacturers create multicomponent particles for targeted delivery.

Respirable drug particles processed through supercritical antisolvent precipitation.

Nevertheless, the PRINT technique shows great promise for manufacturing inhalable drug particles, according to DeSimone. The method can enable continuous manufacturing; provide control of size, shape, and chemical composition; enhance drug stability; and enable particles to be made from otherwise challenging formulations.