Digital light processing (DLP) 3D-printing technology and photoreactive polymers in fabrication of modified-release tablets

In this study, we assessed the feasibility of using digital light processing (DLP) 3D printers (3DP) in fabrication of solid oral dosage forms. The DLP technology uses a digital micromirror device (DMD) that reflects and focuses ultraviolet (UV) light on the surfaces of photoreactive materials that polymerize in a layer-by-layer fashion. Using poly(ethylene glycol) diacrylate (PEGDA) and poly(ethylene glycol) dimethacrylate (PEGDMA) as photoreactive polymers and theophylline as a model drug, we deployed a DLP printer to fabricate tablets. After optimizing various printing parameters including UV intensity and exposure time, layer thickness, and polymer concentration, we printed various types of tablets with and without perforation. We then assessed the tablets for drug content, mechanical strengths, swellability, weight variation, microscopic features, drug-polymer interactions and drug release profiles. The loading of theophylline was 1%, which was independent of tablet weights. The drug content and weight variation were within the acceptable range, as recommended by the United States Pharmacopeia (USP). Scanning electronic microscopic (SEM) pictures showed tablets with distinct layers and smooth outer surfaces. The spectral scans, obtained using Fourier Transform Infrared Spectroscopy (FTIR), showed no chemical interactions between the drug and polymers. Similarly, drug content determined using a UV spectrophotometer was the same as that determined by a high performance liquid chromatography (UPLC). The extent of drug release increased with the increase in the number of perforations in the tablets. Overall, this study demonstrates that DLP 3DP can be used as a platform for fabricating oral tablets with well-defined shapes and different release profiles.