3D-Printed Oral Dosage Forms: Mechanical Properties, Computational Approaches and Applications

Abstract

The aim of this review is to present the factors influencing the mechanical properties of 3D-printed oral dosage forms. It also explores how it is possible to use specific excipients and printing parameters to maintain the structural integrity of printed drug products while meeting the needs of patients. Three-dimensional (3D) printing is an emerging manufacturing technology that is gaining acceptance in the pharmaceutical industry to overcome traditional mass production and move toward personalized pharmacotherapy. After continuous research over the last thirty years, 3D printing now offers numerous opportunities to personalize oral dosage forms in terms of size, shape, release profile, or dose modification. However, there is still a long way to go before 3D printing is integrated into clinical practice. 3D printing techniques follow a different process than traditional oral dosage from manufacturing methods. Currently, there are no specific guidelines for the hardness and friability of 3D printed solid oral dosage forms. Therefore, new regulatory frameworks for 3D-printed oral dosage forms should be established to ensure that they meet all appropriate quality standards. The evaluation of mechanical properties of solid dosage forms is an integral part of quality control, as tablets must withstand mechanical stresses during manufacturing processes, transportation, and drug distribution as well as rough handling by the end user. Until now, this has been achieved through extensive pre- and post-processing testing, which is often time-consuming. However, computational methods combined with 3D printing technology can open up a new avenue for the design and construction of 3D tablets, enabling the fabrication of structures with complex microstructures and desired mechanical properties. In this context, the emerging role of computational methods and artificial intelligence techniques is highlighted.

Keywords: 3D-printing; additive manufacturing; breaking force; friability; hardness; mechanical properties; oral dosage forms; tablets; tensile strength.

Figure 1

Historic timeline of 3D-printing.

Figure 2

Traditional tablet manufacturing process (A) vs. 3D-printing manufacturing process (B).

Figure 3

3D-printed levetiracetam pediatric formulations. (A) Hollow structure, (B) Hollow structure with internal support, (C) Lattice structure.

Figure 4

Immediate release theophylline gaplets. The novel design is based on nine repeating units (blocks) joined together by three bridges. The capsule-like general shape was maintained by using curved side units [76].

Figure 5

3D-printed pregabalin gastrofloating tablets. The internal structure of tablet is composed of a grid infill with void space filled with air so that the tablet has low density, which helps the buoyancy of the tablet in media [32].