A team of researchers has developed a method for producing intestine-targeted tablets using two 3D printing techniques: selective laser sintering (SLS) and fused deposition modeling (FDM).
Led by Thao Tranová, Phd Student from Charles University, contributions also came from the University of Pardubice, the University of Hradec Králové in the Czech Republic, and the Slovak University of Technology in Bratislava.
Published in Macromolecular Materials and Engineering, the study focuses on creating drug formulations designed to delay release until they reach the intestines. This feature could be particularly useful for treating conditions such as inflammatory bowel disease, irritable bowel syndrome, colonic cancer, and celiac disease.
Delivering medication precisely where it is needed has long been a challenge in pharmaceutical research, especially for drugs targeting the intestines. Many formulations release too soon, exposing the drug to stomach acids and reducing its effectiveness. Others rely on coatings that don’t always hold up consistently.
The researchers in this study explored a different approach, using SLS to form the tablet’s core and then applying an FDM-based coating to control the timing of drug release.
Fine-tuning formulation and tablet structure
For the printing process to work effectively, the researchers needed a formulation with the right flow properties, mechanical stability, and printability. After testing different combinations, they found that a mixture of Kollidon VA64, 20% Kollicoat IR, and 0.2% Aeroperl met those requirements.
The cores were printed at a laser speed of 90 mm/s, which offered a balance between durability and controlled disintegration. Once printed, the cores were coated using an FDM-applied shell made of 95% hydroxypropyl methylcellulose (HPMC) and 5% pectin, which played a crucial role in ensuring that the drug stayed intact through stomach acids and only released once it reached the intestines.
To test how well the tablets performed under real-world conditions, the researchers ran dissolution experiments simulating the digestive process. The results confirmed that the coating remained intact in an acidic environment (pH 1.2) for 120 minutes, meaning no drug was released in conditions similar to the stomach.
Once exposed to intestinal conditions (pH 6.8), the drug started dissolving at a controlled rate. Between 255 and 480 minutes, the release followed zero-order kinetics, meaning a steady, predictable amount of the drug was released over time. By the 720-minute mark, 92% of the drug had been released, demonstrating a prolonged and steady release profile.
Beyond dissolution testing, researchers also analyzed the structural properties of the tablets to see how they held up under mechanical stress. Tensile strength tests showed that the laser speed used in SLS printing affected the density and hardness of the tablet cores, with lower speeds producing denser structures.
The addition of Aeroperl improved the flowability of the powder, which led to more uniform sintering and, ultimately, more consistent tablet properties. Additionally, the FDM-applied coating further strengthened the tablets, making them more resistant to handling and transportation while also fine-tuning the drug release.
What makes this approach different from conventional pharmaceutical manufacturing is the level of control it offers. Traditional tablet production relies on compression methods that limit flexibility in design, but 3D printing allows adjustments to both the core and coating composition.
This could allow for more precise formulations tailored to individual patient needs. The researchers also note that hot-melt extrusion, which was used to prepare the coating material, eliminates the need for solvents, an advantage from both an environmental and regulatory perspective.
Before this method can be widely used, further studies will need to explore large-scale production feasibility, regulatory compliance, and clinical performance. Future research may refine the process further, exploring additional formulations and variations in printing parameters to improve efficiency and reliability.
An increase in 3D printed drugs
Several real-world examples highlight how 3D printing is being applied to drug formulation.
Chinese 3D drug printing firm Triastek partnered with global pharmaceutical company Eli Lilly to develop 3D printed oral drugs targeting specific areas of the gastrointestinal tract. Using Triastek’s proprietary Melt Extrusion Deposition (MED) technology, the alliance aimed to create precisely controlled drug release profiles that enhance bioavailability.
As part of the project, researchers first analyzed excipient properties and process parameters to better understand their impact on drug stability. The next phase was set to focus on designing 3D printed structures programmed to release medication at targeted intestinal sites.
Another notable contribution came from University of Santiago de Compostela, MERLN Institute, University College London (UCL) researchers, and UCL spin-out FabRx who developed a method to 3D print tablets in seven seconds.
Unlike traditional vat photopolymerization, which prints pills layer by layer, their volumetric printing technique cures entire vats of resin in a single step, significantly increasing production speed. The approach was tested using six different resins with paracetamol as a model drug, yielding pills with tunable drug release profiles. Scientists believe this method could streamline personalized medicine production, including “polypills” combining multiple medications.
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Featured image shows FDM-coated core. Image via Charles University.
