Development and Evaluation of a Novel Cup-Shaped Tablet-in-Tablet Tool for Varied Drug Release Dosage Form

The fabrication of tablet-in-tablet (TiT) dosage form presents intense engineering challenges, chiefly in preserving themechanical integrity of the outer shell while shielding fragile, functionally-coated inner tablets from the extremeforces of high-velocity compression. This investigation describes a systematic, engineering-led methodology for thedevelopment of a novel cup-shaped tablet tooling set, achieved through five rigorous design-build-test iterations. Theoptimization efforts centered aroundthe critical geometric parameters, primarily the peripheral rim architecture towithstand mechanical stresses and the internal cup geometry to manage stress even distribution. Initial prototypesexhibited catastrophic mechanical failures, due to critical rim fragility. A subsequent design featuring a geometricallyreinforced periphery successfully protected the inner enteric coated tablet integrity and achieved robust mechanicalstrength (Hardness: 8.8–12.8 KP), yet it revealed a susceptibility to attrition during post-compression coating. The final optimized designTool-5, achieved success by synergistically integrating this reinforced periphery with a stress-dissipating internal fillet and a refined surface curvature for process durability, which facilitated the uniform redistribution of compaction forces. Tablets produced with this tool demonstrated superior quality attributes,including high crushing strength (9.2–14.4 KP) and meeting friability acceptance criteria (NMT 1.0%), whileassuring the complete preservation of the enteric film integrity of the inner tablet. These results unequivocallyestablish that precision tooling geometry is a critical control parameter in TiT manufacturing, offering a replicableengineering framework for the reliable production of complex novel oral solid dosage forms.