Fabrication of an osmotic 3D printed solid dosage form for controlled release of active pharmaceutical ingredients

In pharmaceutical formulations, pharmacokinetic behavior of the Active Pharmaceutical Ingredients (API's) is significantly affected by their dissolution profiles. In this project, we attempted to create personalized dosage forms with osmotic properties that exhibit different API release patterns via Fused Deposition Modelling (FDM) 3D printing. Specifically, cellulose acetate was employed to create an external shell of an osmotically active core containing Diltiazem (DIL) as model drug. By removing parts of the shell (upper surface, linear lateral segments) were created dosage forms that modify their shape at specific time frames under the effect of the gradually induced osmotic pressure. Hot-Melt Extrusion (HME) was employed to fabricate two different 3DP feeding filaments, for the creation of either the shell or the osmotic core (dual-extrusion printing). Printed formulations and filaments were characterized by means of (TGA, XRD, DSC) and inspected using microscopy (optical and electron). The mechanical properties of the filaments were assessed by means of micro- and macro mechanical testing, whereas micro-Computed Tomography (μCT) was employed to investigate the volumetric changes occurring during the hydration process. XRD indicated the amorphization of DIL inside HME filaments and printed dosage forms, whereas the incorporated NaCl (osmogen) retained its crystallinity. Mechanical properties' testing confirmed the printability of produced filaments. Dissolution tests revealed that all formulations exhibited sustained release differing at the initiation time of the API dissolution (0, 120 and 360 min for the three different formulations). Finally, μCT uncovered the key structural changes associated with distinct phases of the release profile. The above results demonstrate the successful utilization of an FDM 3D printer in order to create osmotic 3D printed formulations exhibiting sustained and/or delayed release, that can be easily personalized containing API doses corresponding to each patient's specific needs.