3D Printing of Pharmaceutical Dosage Forms: A Review

Three-dimensional (3D) printing, or additive manufacturing, is a newer route to making medicines in which a dosage form is assembled layer upon layer from a computer-generated model. In contrast to traditional production, the approach lets formulators adjust dose, size, shape, internal geometry, composition and drug-release behaviour to suit the needs of each patient. This review outlines the main printing technologies used for pharmaceuticals, namely binder jetting, fused deposition modelling (FDM), semi-solid extrusion (SSE), material extrusion deposition (MED), stereolithography (SLA) and digital light processing (DLP), and describes the materials and excipients that make successful printing possible. Polymers have a central role, supplying structural strength, printability and control over drug release, whereas plasticizers, lubricants, disintegrants, fillers, binders and other additives affect how the formulation is processed and how the finished product performs. The main quality parameters discussed are mechanical and tensile strength, structural fidelity, layer adhesion, resolution, drug distribution and release profile. Possible uses include personalized medicine, paediatric and geriatric treatment, preclinical research, veterinary products and cancer surgery. Even so, expensive equipment, a narrow choice of printable pharmaceutical materials, drugs that are sensitive to heat or light, difficulties in scale-up, reproducibility, quality control and still-developing regulation continue to hold the field back. On balance, 3D printing offers a promising path to adaptable, patient-centred and individualized dosage forms.