Dissolution of fluconazole from 3D-printed prolonged-release tablets: a quantitative evaluation

Among the many applications of additive technologies, their use in drug formulation holds a particularly important place. Numerous studies have been conducted on using various 3D printing techniques to produce both immediate- and modified-release dosage forms. However, the drug release mechanism may vary depending on the manufacturing method and formulation composition. This work aimed to analyze the influence of the 3D printing method used on the mechanism of fluconazole release from prolonged-release tablets. We conducted an analysis of tablets containing 50 mg of fluconazole, produced using two 3D printing techniques: Fused Deposition Modeling (FDM) and Liquid Crystal Display (LCD, classified as one of the Vat Photopolymerization (VPP) methods). Because FDM and VPP techniques build objects in fundamentally different ways, a unique set of excipients was used for each of these methods. For the FDM-printed tablets, poly(vinyl alcohol) was used to control drug release and as the filament-forming polymer. The tablet matrix produced using the VPP method was based on the cross-linked polyethylene glycol diacrylate. Both formulations were characterized by prolonged release of API. Employing surface dissolution imaging and kinetic models, we demonstrated that in the case of FDM-printed tablets, the API release is mainly regulated by the relaxation and gradual decay of the water-soluble polymer. In contrast, the relaxation of the water-insoluble matrix of VPP tablets was negligible. Although the diameter of the VPP tablets increased slightly during the dissolution study, the API release was primarily controlled by the diffusion of fluconazole through the cross-linked polymer.