3D-printed ethylcellulose matrix for gastroretentive delivery: Fabrication and characterization of sustained-release metformin hydrochloride tablets.

This study introduces an innovative approach for manufacturing gastroretentive floating tablets (GRFTs) using semisolid extrusion (SSE) 3D printing to overcome the limitations of conventional delivery systems. Hydrophobic ethylcellulose (EC) was employed as a primary structural matrix to incorporate metformin hydrochloride (MET). Four formulations were systematically evaluated based on EC concentration, focusing on their physicochemical properties, floating behavior, and release kinetics. The 3D-printed MET tablets (3DP-METs) exhibited immediate buoyancy and sustained flotation exceeding 24 h in pH 1.2 medium. In vitro studies demonstrated controlled drug release over 12 h, with the optimized formulation (F2, 20% EC) showing a similarity factor (f2) of 60.11 compared to the commercial reference. In vivo X-ray imaging in rabbits indicated that the 3DP-MET remained structurally intact and was retained in the gastric region for over 18 h. Furthermore, pharmacokinetic analysis revealed that 3DP-MET showed a moderately higher initial drug absorption (higher Cmax with an earlier Tmax) while maintaining a comparable AUC to the commercial product. In conclusion, this research demonstrates that this ethylcellulose-based (SSE) 3D printing approach serves as a versatile platform technology, offering a customizable alternative to traditional gastroretentive formulations for drugs with narrow absorption windows.