3D printing by fused deposition modeling (FDM) of a swellable/erodible capsular device for oral pulsatile release of drugs

The aim of the present work was to explore the feasibility of fused deposition modeling (FDM) 3D printing in the manufacturing of capsular devices for oral pulsatile release based on a swellable/erodible polymer (hydroxypropyl cellulose, HPC). This involved an experimental evaluation of the possibility of fabricating hollow structures via FDM and the production of HPC filaments by hot melt extrusion (HME), which are not commercially available. Moreover, the set-up of appropriate computer aided design files had to be faced. A twin-screw extruder equipped with a rod-shaped die and a purposely designed pulling/calibrating device as well as a MakerBot Replicator 2 3D printer were employed for HME and FDM processing, respectively. Bodies and caps with satisfactory physico-technological properties were obtained. The release test of assembled capsular devices pointed out a lag phase before rapid and quantitative liberation of the drug. The morphological changes undergone by the device when in contact with water and their release performance turned out comparable with those of analogous systems fabricated by injection molding. The possibility of manufacturing capsular devices for oral pulsatile release by FDM 3D printing starting from HPC filaments purposely prepared was thus demonstrated, and the real-time prototyping potential of FDM was assessed.