The Use of 3D Printed Molds to Cast Tablets with a Designed Disintegration Profile

The Use of Additive Manufacturing Techniques in the Development of Polymeric Molds: A Review

The continuous growth of additive manufacturing in worldwide industrial and research fields is driven by its main feature which allows the customization of items according to the customers' requirements and limitations. There is an expanding competitiveness in the product development sector as well as applicative research that serves special-use domains. Besides the direct use of additive manufacturing in the production of final products, 3D printing is a viable solution that can help manufacturers and researchers produce their support tooling devices (such as molds and dies) more efficiently, in terms of design complexity and flexibility, timeframe, costs, and material consumption reduction as well as functionality and quality enhancements. The compatibility of the features of 3D printing of molds with the requirements of low-volume production and individual-use customized items development makes this class of techniques extremely attractive to a multitude of areas. This review paper presents a synthesis of the use of 3D-printed polymeric molds in the main applications where molds exhibit a major role, from industrially oriented ones (injection, casting, thermoforming, vacuum forming, composite fabrication) to research or single-use oriented ones (tissue engineering, biomedicine, soft lithography), with an emphasis on the benefits of using 3D-printed polymeric molds, compared to traditional tooling.

Quality control evaluation of paediatric chocolate-based dosage forms: 3D printing vs mold-casting method

Pharmaceutical compounding is a core activity in the preparation of patient-specific dosage forms. In the current study we aimed to investigate whether 3D printing could be employed for the preparation of pediatric-friendly personalized dosage forms that fulfil the acceptance criteria specified in the pharmacopoeias for conventional dosage forms. We then compared the 3D printed dosage forms with the same formulations prepared with mold-casting, a method frequently applied during pharmaceutical compounding. The molded dosage forms failed to pass most of the quality control tests, including the mass uniformity and content uniformity tests, as well as dose accuracy, contrary to the 3D printed, which not only passed all tests but also enabled precision overdose adjustment. Hence, 3D printing of chocolate-based dosage forms may effectively serve as an acceptable alternative method to mold casting in compounding patient-specific medication at the point-of-care.

3D Printing of Thermo-Sensitive Drugs

Three-dimensional (3D) printing is among the rapidly evolving technologies with applications in many sectors. The pharmaceutical industry is no exception, and the approval of the first 3D-printed tablet (Spiratam^®) marked a revolution in the field. Several studies reported the fabrication of different dosage forms using a range of 3D printing techniques. Thermosensitive drugs compose a considerable segment of available medications in the market requiring strict temperature control during processing to ensure their efficacy and safety. Heating involved in some of the 3D printing technologies raises concerns regarding the feasibility of the techniques for printing thermolabile drugs. Studies reported that semi-solid extrusion (SSE) is the commonly used printing technique to fabricate thermosensitive drugs. Digital light processing (DLP), binder jetting (BJ), and stereolithography (SLA) can also be used for the fabrication of thermosensitive drugs as they do not involve heating elements. Nonetheless, degradation of some drugs by light source used in the techniques was reported. Interestingly, fused deposition modelling (FDM) coupled with filling techniques offered protection against thermal degradation. Concepts such as selection of low melting point polymers, adjustment of printing parameters, and coupling of more than one printing technique were exploited in printing thermosensitive drugs. This systematic review presents challenges, 3DP procedures, and future directions of 3D printing of thermo-sensitive formulations.

Controlling drug release with additive manufacturing-based solutions

3D printing is an innovative manufacturing technology with great potential to revolutionise solid dosage forms. Novel features of 3D printing technology confer advantage over conventional solid dosage form manufacturing technologies, including rapid prototyping and an unparalleled capability to fabricate complex geometries with spatially separated conformations. Such a novel technology could transform the pharmaceutical industry, enabling the production of highly personalised dosage forms with well-defined release profiles. In this work, we review the current state of the art of using additive manufacturing for predicting and understanding drug release from 3D printed novel structures. Furthermore, we describe a wide spectrum of 3D printing technologies, materials, procedure, and processing parameters used to fabricate fundamentally different matrices with different drug releases. The different methods to manipulate drug release patterns including the surface area-to-mass ratio, infill pattern, geometry, and composition, are critically evaluated. Moreover, the drug release mechanisms and models that could aid exploiting the release profile are also covered. Finally, this review also covers the design opportunities alongside the technical and regulatory challenges that these rapidly evolving technologies present.

3D printed mold-based capsaicin candy for the treatment of oral ulcer

Oral ulcer is one common mucosal disease with high prevalence. Here, capsaicin candies were prepared based on the stereolithographically (SLA) 3D printed molds. The molds can be freely designed depending on the needs of patients, involving symmetric shapes (e.g., round, four-lead clover and cube), asymmetric shapes (e.g., car) and various color (e.g., blue, red and yellow). A two-part-combined mold was filled with the xylitol-based material and separated to obtain hard candies. Capsaicin was amorphous in the candies according to the differential scanning calorimetry and X-ray diffraction. Poloxamer 188 improved the release of capsaicin from the candies. Rat oral ulcer models were established on the tongue with phenol liquids. The blank candy, 0.05% capsaicin candy and dexamethasone were respectively administered on the ulcer once daily. On Day 7, a healing rate of 97.8% was achieved by the capsaicin candy, much higher than those in the other groups. Moreover, the blank candy also showed the remarkable ulcer healing effect due to the presence of xylitol and poloxamer. Capsaicin remarkably enhanced the reepithelialization of ulcer tissues and showed strong anti-inflammatory effect by reducing the expressions of THF-α and IL-6. 3D printing-based capsaicin candies provide an interesting therapeutic choice for the people with oral ulcer.

An Effective Technology for the Development of Immediate Release Solid Dosage Forms Containing Low-Dose Drug: Fused Deposition Modeling 3D Printing

PURPOSE

Fabrication of immediate release (IR) tablet formulations with rapid release profile via fused deposition modeling 3D printing (FDM 3DP) is a challenge. The aims of this study were to prepare IR tablets with different dissolution profiles and to increase their in vitro dissolution rates by making physical modifications on them. Pramipexole was used as the model low-dose drug.

METHODS

Polymeric filaments were prepared with six different combinations of Eudragit EPO and poly(ethylene) oxide by hot melt extrusion and 3D tablets were produced using an FDM printer. Characterization studies for the filaments and tablets were carried out. The printability of the filaments was also evaluated using a novel mechanical characterization method. Tablet formulation with optimum dissolution profile was chosen and physical modifications (infill %, shape change and thickness) on this formulation were made.

RESULTS

Low-dose pramipexole loading filaments and 3D tablets were homogenously prepared. The printability of the filaments was related to their flexibility. With the physical modifications, the drug release completion time of the tablets reduced to 5 min.

CONCLUSIONS

The same rapid release profiles with conventional IR tablets can be reached by making only physical changes on 3D tablets without using any filling or disintegrating agents.