Influence of Drug Type on the Polymerization and Performance of 3D-Printed Biodegradable Drug Delivery Devices

Vat polymerization (VP), an additive manufacturing technique, has emerged as a promising tool for the fabrication of controlled drug delivery devices. Drugs can easily be incorporated into photopolymerizable liquid resins without concerns of thermal degradation associated with traditional additive manufacturing techniques. Furthermore, these drug-loaded resins can be three-dimensional (3D) printed into devices with an improved speed and resolution not afforded by traditional additive manufacturing techniques. However, the effect of different drug physicochemical properties on the fabrication of these devices and subsequent drug release behavior have not been thoroughly investigated. In this work, we systematically investigate the influence of physicochemical parameters, such as water solubility, resin solubility, and light absorption, on the resulting fabrication and release performance of biodegradable drug delivery devices. We evaluated four model drugs, rhodamine B (RhB), 2-(4-hydroxyphenylazo)benzoic acid (HABA), Allura red AC (AR), and riboflavin, and determined their effects on photopolymerization and printing parameters using photorheology and working curve measurements. Their effects on drug release behavior or performance were also characterized using in vitro release studies. It was shown that the light absorption characteristics of the drug had a significant effect on the printability of the resulting devices. The solubility of the drugs in the resin also had an impact on their release and the release mechanism. This study serves to deepen the current understanding of how to utilize VP to fabricate controlled drug delivery devices with different drug types.