2.5D Printing of Drug-Delivery Microspheres from Melt

Polymer-based drug-delivery microspheres are used to encaptivate, protect and release an active ingredient to a specific location in a patient`s body. Here we describe a novel method, named 2.5D Printing, for producing polymeric microspheres by printing a molten jet onto a superoleophobic surface; potentially overcoming the substantial shortcomings of existing techniques. In 2.5D Printing, a molten polymer-drug blend is deposited to a surface; yet, unlike 2D or 3D printing, the surface is not wetted and discrete spherical microparticles are formed. Using high-speed imaging capturing the sphere formation process, we found that plethora of physical events are involved during the milliseconds` process of microsphere printing: jetting, filament formation and break up, de-wetting, solidification, and crystallization. Interestingly, we found intricate phenomena governing both the mechanism of sphere-formation and the resulting drug-release mechanism from ibuprofen-loaded PCL (IBU-PCL) and PLGA (IBU-PLGA) microspheres. The resulting microspheres exhibit (1) high sphericity, (2) high drug encapsulation efficiencies, with distinctly high process yield (>95%), as opposed to conservative solvent-based methods used today, (3) reproducible size and shape and (4) varying IBU controlled release kinetics.