Caffeine–Acrylic Resin DLP-Manufactured Composite as a Modern Biomaterial

Materials based on photocurable resins and pharmaceutically active agents (APIs) are gaining interest as a composite drug delivery system. In this study, a composite of caffeine with acrylic resin was obtained using an additive manufacturing method of digital light processing (DLP) as a potential material for transdermal drug delivery. The mechanical properties of the composites and the ability to release caffeine from the resin volume in an aqueous environment were investigated. The amount of caffeine in the resulting samples before and after release was evaluated using a gravimetric method. The global thresholding method was also evaluated for its applicability in examining caffeine release from the composite. It was shown that as the caffeine content increased, the strength properties worsened and the ability to release the drug from the composite increased, which was caused by negligible interfacial interactions between the hydrophilic filler and the hydrophobic matrix. The global thresholding method resulted in similar caffeine release rate values compared to the gravimetric method but only for samples in which the caffeine was mainly located near the sample surface. The distribution of caffeine throughout the sample volume made it impossible to assess the caffeine content of the sample using global thresholding.