Impact of drug load and polymer molecular weight on the 3D microstructure of printed tablets

This study investigates the influence of drug load and polymer molecular weight on the structure of tablets three-dimensionally (3D) printed from the binary mixture of prednisolone and hydroxypropyl methylcellulose (HPMC). Three different HPMC grades, (AFFINISOLTM HPMC HME 15LV, 90 Da (HPMC 15LV); 100LV, 180 Da (HPMC 100LV); 4M, 500 Da (HPMC 4M)), which are suitable for hot-melt extrusion (HME), were used in this study. HME was used to fabricate feedstock material, i.e., filaments, at the lowest possible extrusion temperature. Filaments of the three HPMC grades were prepared to contain 2.5, 5, 10 and 20 % (w/w) prednisolone. The thermal degradation of the filaments was studied with thermogravimetric analysis, while solid-state properties of the drug-loaded filaments were assessed with the use of X-ray powder diffraction. Prednisolone in the freshly extruded filaments was determined to be amorphous for drug loads up to 10%. It remained physically stable for at least 6 months of storage, except for the filament containing 10% drug with HPMC 15LV, where recrystallization of prednisolone was detected. Fused deposition modeling was utilized to print honeycomb-shaped tablets from the HME filaments of HPMC 15LV and 100LV. The structural characteristics of the tablets were evaluated using X-ray microcomputed tomography, specifically porosity and size of structural elements were investigated. The tablets printed from HPMC 15LV possessed in general lower total porosity and pores of smaller size than tablets printed from the HPMC 100LV. The studied drug loads were shown to have minor effect on the total porosity of the tablets, though the lower the drug load was, the higher the variance of porosity along the height of the tablet was observed. It was found that tablets printed with HPMC 15LV showed higher structural similarity with the virtually designed model than tablets printed from HPMC 100LV. These findings highlight the relevance of the drug load and polymer molecular weight on the microstructure and structural properties of 3D printed tablets.

Orthotics and prosthetics by 3D-printing: Accelerating its fabrication flow

Orthoses and socket prostheses are rarely used orthopaedic devices in veterinary medicine. Recently, more pet owners have sought these treatments for pets with orthopaedic conditions. However, veterinarians often lack substantial scientific evidence on device outcomes and may expect high costs, the main limiting factor, if human orthopaedic market prices are assumed. This discrepancy creates an imbalance between pet owners' expectations, veterinarians' recommendations, and actual patient benefits. To address economic constraints and enhance knowledge about these devices, this study used 3D technology-namely 3D scanning and printing via fused deposition modelling-to design, modify, and manufacture orthoses and socket prostheses for ten patients, including nine dogs and one calf. An equation was devised and applied to all printed devices to streamline the resizing process for sockets and orthoses. The 3D-printed devices were fitted to the patients, and their adaptation was assessed using three novel scales based on prior scientific literature in the small animal orthopaedic field. The orthoses were well-tolerated, with successful and straightforward adaptation. Although socket prostheses were tolerated, the dogs' adaptation was suboptimal, while the calf demonstrated excellent and immediate adaptation.

Optimisation of the additive manufacturing parameters of polylactic acid (PLA) cellular structures for biomedical applications

Fused deposition modelling (FDM) is an additive manufacturing technology used to create functional and complex geometries directly from computer-generated models. This technique can be utilised to generate cellular structures with controllable pore size, pore shape, and porosity. Cellular structures are fundamental in orthopaedics scaffolds because of its low elastic modulus, high compressive strength, and adequate cell accommodation spaces. This paper aims at investigating and optimising the FDM additive manufacturing process parameters of polylactic Acid (PLA) for two lattice structures namely Schoen Gyroid and Schwarz Primitive. The effect of additive manufacturing critical process parameters including layer height, flow rate, and print speed on the geometrical accuracy and compressive strength of the specimens were analysed. In addition, other parameters that have minimal effect on the geometrical accuracy of the printed parts were discussed. A Full Factorial Analysis (FFA) using Minitab software was undertaken to identify the perfect combination of printing parameters to provide the most geometrically accurate structure. In this study, samples of the Schoen Gyroid and the Schwarz Primitive lattices and a solid control cylinder were 3D printed using the ideal printing combination to assess the manufacturability, the geometrical accuracy, and the mechanical behaviour of both designs. It was found that the optimised FDM process parameters for the studied cellular structures were a layer height of 0.16 mm, a printing speed of 50 mm/s and a flow rate of 90%. As a result of using these parameters, the solid, Schoen Gyroid and Schwarz Primitive specimens demonstrated elastic moduli values of 951 MPa, 264 MPa, and 221 MPa, respectively. In addition, the Schoen Gyroid and the Schwarz Primitive have reached their stress limits at around 8.68 MPa and 7.06 MPa, respectively. It was noticed that the Schoen Gyroid structure exhibited ∼ 18% higher compressive strength and ∼ 16% higher elastic modulus compared to the Schwarz Primitive structure for the same volume fraction of porosity, overall dimensions, and the manufacturing process parameters. Although both structures revealed mechanical properties that fall within the range of the human trabecular bone, but Schoen Gyroid exhibited improved structural integrity performance that is evident by its post-yield behaviour.

Fused deposition modelling approach using 3D printing and recycled industrial materials for a sustainable environment: a review

According to research findings of many peer-reviewed studies, up to 90% of household items may be made of plastic. But nowadays, just a small portion of plastic waste is recycled. Plastic pyrolysis and polymer breakdown are environmentally hazardous. Processing is, therefore, necessary for recycling. Plastics are constantly being manufactured and require minimal processing, necessitating innovation. Plastic recycling is becoming a major issue for environmentalists and waste management professionals. Fused deposition modelling, or FDM, is one of the most popular types of additive manufacturing. It uses the melt extrusion process to deposit filaments of thermal polymers in a predetermined pattern. Using a computer-generated design, 3D printing, sometimes referred to as additive manufacturing, is a technique for building three-dimensional objects layer by layer. A 3D item is produced by the additive method of 3D printing, which involves building up layers of material. To make a three-dimensional object, FDM printers eject a thermoplastic filament that has been heated to its melting point layer by layer. 3D printing is a rapidly expanding industry and the market in this field has grown up to 23% by 2021. Several experiments on new 3D printing materials have been carried out to reduce pollution and the supply of plastic. Various additives have been investigated to increase recycled polymers' molecular weight and mechanical properties. The most frequent type of fibre found in that is thermoplastic fibre. In this instance, waste ABS (acrylonitrile butadiene styrene) plastic from industrial FDM printers was gathered and examined in a bustling open shop. In this review, we discussed the use of recyclable polymers in 3D printing for waste material management.

Impact of rGO-coated PEEK and lattice on bone implant

The composite coating can effectively inhibit bacterial proliferation and promote the expression of bone-building genes in-vitro. Therefore, a novel production was used to produce poly-ether-ether-ketone, and reduced graphene oxide (PEEK-rGO) scaffolds with ratios of 1-3%, combining a different lattice for a bone implant. An inexpensive method was developed to prepare the new coatings on the PEEK scaffold with reduced graphene oxide (rGO). Mechanical testing, data analysis and cell culture tests for in-vitro biocompatibility scaffold characterisation for the PEEK composite were conducted. Novel computation microanalysis of four-dimensional (4D) printing of microstructure of PEEK-rGO concerning the grain size and three dimensional (3D) morphology was influenced by furrow segmentation of grains cell growth on the composite, which was reduced from an average of 216-155 grains and increased to 253 grains on the last day. The proposed spherical nanoparticles cell grew with time after dispersed PEEK nanoparticles in calcium hydroxyapatite (cHAp) grains. Also, the mechanical tests were carried out to validate the strength of the new composites and compare them to that of a natural bone. The established 3D-printed PEEK composite scaffolds significantly exhibited the potential of bone implants for biomimetic heterogeneous bone repair.

Direct Granule Feeding of Thermal Droplet Deposition 3D Printing of Porous Pharmaceutical Solid Dosage Forms Free of Plasticisers

Purpose

To develop a new direct granule fed 3D printing method for manufacturing pharmaceutical solid dosage forms with porous structures using a thermal droplet deposition technology.

Methods

Eudragit® E PO was used as the model polymer, which is well-known to be not FDM printable without additives. Wet granulation was used to produce drug loaded granules as the feedstock. The flow and feedability of the granules were evaluated. The physicochemical properties and in vitro drug release performance of the granules and the printed tablets were fully characterised.

Results

Using the method developed by this study, Eudragit E PO was printed with a model drug into tablets with infills ranging from 30–100%, without additives. The drug was confirmed to be molecularly dispersed in the printed tablets. The printing quality and performances of the porous tablets were confirmed to be highly compliant with the pharmacopeia requirement. The level of infill density of the porous tablets had a significant effect on their in vitro drug release performance.

Conclusion

This is the first report of thermal droplet deposition printing via direct granule feeding. The results of this study demonstrated that this new printing method can be used as a potentially valuable alternative for decentralised pharmaceutical solid dosage form manufacturing.