Effect of Tartrazine as Photoabsorber for Improved Printing Resolution of 3D Printed “Ghost Tablets”: Non-Erodible Inert Matrices

Stereolithography (SLA) 3D printing of pharmaceuticals suffers from the problem of light scattering, which leads to over-curing, resulting in the printing of objects that are non-compliant with design dimensions and the overloading of drugs. To minimize this problem, photoabsorbers such as tartrazine (food grade) can be used to absorb the stray light produced by scattering, leading to unintended photopolymerization. Ghost tablets (i.e., non-erodible inert matrices) were additively manufactured using SLA with varying ratios of polyethylene glycol diacrylate (PEGDA): polyethylene glycol (PEG) 300, along with tartrazine concentrations. The 3D printed ghost tablets containing maximum (0.03%) tartrazine were extremely precise in size and adhered to the nominal value of the metformin hydrochloride content. Resolution analysis reinstated the influence of tartrazine in achieving highly precise objects of even 0.07 mm2 area. Furthermore, 3D printed ghost tablets were characterized using analytical means, and swelling studies. Additionally, ghost tablets were tested for their mechanical robustness using dynamic mechanical and texture analysis, and were able to withstand strains of up to 5.0% without structural failure. The printed ghost tablets displayed a fast metformin hydrochloride release profile, with 93.14% release after 12 h when the PEG 300 ratio was at its maximum. Ghost tablets were also subjected to in vivo X-ray imaging, and the tablets remained intact even after four hours of administration and were eventually excreted in an intact form through fecal excretion.