Volumetric printing and non-destructive drug quantification of water-soluble supramolecular hydrogels

Vat photopolymerisation 3D printing is being actively explored for manufacturing personalised medicines due to its high dimensional accuracy and lack of heat application. However, several challenges have hindered its clinical translation, including the inadequate printing speeds, the lack of resins that give soluble matrices, and the need for non-destructive quality control measures. In this study, for the first time, a rapid approach to producing water-soluble vat photopolymerised matrices and a means of non-destructively verifying their drug content were investigated. Volumetric printing, a novel form of vat photopolymerisation, was used to fabricate personalised warfarin-loaded 3D-printed tablets (printlets). Eight different formulations containing varying amounts of warfarin (0.5-6.0% w/w) were used to print two different sized torus-shaped printlets within 6.5 to 11.1 s. Nuclear magnetic resonance (NMR) spectroscopy revealed the presence of only trace amounts of unreacted acrylate monomers, suggesting that the photopolymerisation reaction had occurred to near completion. All printlets completely solubilised and released their entire drug load within 2.5 to 7 h. NIR spectroscopy (NIRS) was used to non-destructively verify the dose of warfarin loaded into the vat photopolymerised printlets. The partial least square regression model built showed strong linearity (R² = 0.980), and high accuracy in predicting the drug loading of the test sample (RMSEP = 0.205%). Therefore, this study advances pharmaceutical vat photopolymerisation by demonstrating the feasibility of producing water-soluble printlets via volumetric printing and quantifying the drug load of vat photopolymerised printlets with NIRS.