4D printing of shape-memory polymer-based floating tablets via fused deposition modelling: Transformable helical structure to tablet-like form

The integration of four-dimensional (4D) printing technology into pharmaceutical manufacturing has introduced a transformative approach to drug delivery systems, offering flexible alternatives to improve drug bioavailability. This study advanced the field by developing an innovative 4D-printed floating drug delivery system using Fused Deposition Modelling (FDM) and a temperature-responsive polymer, polylactic acid (PLA). Unlike traditional methods and previous literature that relied on external devices or encapsulation, our approach utilised the shape-memory properties of PLA to create helical structures that transform into tablet-like forms when heated and subjected to an external force. Under gastric conditions, these structures reverted to their original shape, allowing them to float and release drugs over an extended period. In this work, eight helical models (M1 to M8), were designed and fabricated with varying geometric parameters, including helix diameter, number of helical turns, and top/base height, to assess their geometric accuracy, shape-memory performance, drug-loading efficiency, floatability, and release behaviour. Results showed that models with smaller helix diameters and fewer turns exhibited superior shape recovery, with the highest observed at 79.5% for Model M1 (1.0 mm helix diameter, two helical turns, and 0.5 mm top/base height). Meanwhile, models with larger diameters showed higher drug-loading capacities. Additionally, the drug-loaded models demonstrated significant shape-recovery and floating performances, suggesting the potential for prolonging drug release for up to 12 h. These findings highlight the potential of 4D printing in developing advanced drug delivery systems, providing new insights into how this technology can improve drug administration and drug delivery through shape-changing tailored systems.