'Temporary Plasticiser': A novel solution to fabricate 3D printed patient-centred cardiovascular 'Polypill' architectures

Three-dimensional printing technology as a promising tool in bioavailability enhancement of poorly water-soluble molecules: A review

Poor aqueous solubility of active pharmaceutical ingredients (API) is nowadays a major issue in the pharmaceutical field. The combinatorial chemistry provides more and more API with a great therapeutic potential, but with a low aqueous solubility. Among the strategies to overcome this drawback, the use of amorphous solid dispersions (ASD), as well as the increase of surface area, is widely used. The three dimensional (3D) printing technologies appear to be innovative tools allowing the construction of any unconventional forms with different composition, structure or infill; especially by using ASD materials. This review aims to deliver notions about the different 3D printing techniques found in the literature to improve aqueous solubility of several API, namely nozzle-based method, inkjet methods and laser- based methods, as well as guide formulator in terms of formulation parameters that have to be optimized to allow the most suitable impression of innovative medicines.

Benefits and Prerequisites Associated with the Adoption of Oral 3D-Printed Medicines for Pediatric Patients: A Focus Group Study among Healthcare Professionals

The utilization of three-dimensional (3D) printing technologies as innovative manufacturing methods for drug products has recently gained growing interest. From a technological viewpoint, proof-of-concept on the performance of different printing methods already exist, followed by visions about future applications in hospital or community pharmacies. The main objective of this study was to investigate the perceptions of healthcare professionals in a tertiary university hospital about oral 3D-printed medicines for pediatric patients by means of focus group discussions. In general, the healthcare professionals considered many positive aspects and opportunities in 3D printing of pharmaceuticals. A precise dose as well as personalized doses and dosage forms were some of the advantages mentioned by the participants. Especially in cases of polypharmacy, incorporating several drug substances into one product to produce a polypill, personalized regarding both the combination of drug substances and the doses, would benefit drug treatments of several medical conditions and would improve adherence to medications. In addition to the positive aspects, concerns and prerequisites for the adoption of 3D printing technologies at hospital settings were also expressed. These perspectives are suggested by the authors to be focus points for future research on personalized 3D-printed drug products.

Polymers for Extrusion-Based 3D Printing of Pharmaceuticals: A Holistic Materials-Process Perspective

Three dimensional (3D) printing as an advanced manufacturing technology is progressing to be established in the pharmaceutical industry to overcome the traditional manufacturing regime of 'one size fits for all'. Using 3D printing, it is possible to design and develop complex dosage forms that can be suitable for tuning drug release. Polymers are the key materials that are necessary for 3D printing. Among all 3D printing processes, extrusion-based (both fused deposition modeling (FDM) and pressure-assisted microsyringe (PAM)) 3D printing is well researched for pharmaceutical manufacturing. It is important to understand which polymers are suitable for extrusion-based 3D printing of pharmaceuticals and how their properties, as well as the behavior of polymer-active pharmaceutical ingredient (API) combinations, impact the printing process. Especially, understanding the rheology of the polymer and API-polymer mixtures is necessary for successful 3D printing of dosage forms or printed structures. This review has summarized a holistic materials-process perspective for polymers on extrusion-based 3D printing. The main focus herein will be both FDM and PAM 3D printing processes. It elaborates the discussion on the comparison of 3D printing with the traditional direct compression process, the necessity of rheology, and the characterization techniques required for the printed structure, drug, and excipients. The current technological challenges, regulatory aspects, and the direction toward which the technology is moving, especially for personalized pharmaceuticals and multi-drug printing, are also briefly discussed.

Development of 3D Printed Tablets by Fused Deposition Modeling Using Polyvinyl Alcohol as Polymeric Matrix for Rapid Drug Release

In this study, the processability of polyvinyl alcohol (PVA), a water-soluble polymer, into melt-extruded filaments and then into 3D printed tablets by fused deposition modeling was studied. PVA is semicrystalline with Tg and m.p. of ~45°C and ~190°C, respectively. After screening several plasticizers, sorbitol was selected to enhance melt extrudability of PVA. Carvedilol and haloperidol, 2 basic compounds with pH-dependent solubility, were used as model drugs. Miscibility of the drugs with PVA, with and without added sorbitol as plasticizer, was also tested to determine whether any amorphous solid dispersion was formed that would facilitate rapid and pH-independent dissolution. Finally, the drug release from physical mixtures, crushed extrudates, and printed tablets were determined. Owing to high m.p. and high melt viscosity of PVA, filaments containing 10% and 20% drug required 180°C-190°C for extrusion, which could be reduced to ~150°C by adding 10% sorbitol. The printing temperature of 210°C was, however, required. Miscibility of carvedilol and haloperidol with PVA were, respectively, ~20% and <10%. PVA provided complete drug release from 3D printed tablets with 10% and 20% carvedilol and 60% infill in ~45 min at both pH 2 and 6.8. However, despite relatively rapid dissolution rate, high processing temperature and limited drug-polymer miscibility could be potential development issues with PVA.

High Content Solid Dispersions for Dose Window Extension: A Basis for Design Flexibility in Fused Deposition Modelling

PURPOSE

This study uses high drug content solid dispersions for dose window extension beyond current demonstrations using fused deposition modelling (FDM) to; i) accommodate pharmaceutically relevant doses of drugs of varying potencies at acceptable dosage form sizes and ii) enable enhanced dose flexibility via modular dosage form design concepts.

METHODS

FDM was used to generate ~0.5 mm thick discs of varying diameter (2-10 mm) from melt-extruded feedstocks based on 10% to 50% w/w felodipine in ethyl cellulose. Drug content was determined by UV spectroscopy and dispensing precision from printed disc mass.

RESULTS

Mean felodipine content was within ±5% of target values for all print volumes and compositions including contents as high as ~50% w/w. However, poor dispensing precision was evident at all print volumes.

CONCLUSIONS

In pursuit of dose flexibility, this successful demonstration of dose window extension using high content solid dispersions preserves FDM design flexibility by maintaining applicability to drugs of varying potencies. The achieved uniformity of content supports the application of varying content solid dispersions to modular dosage form concepts to enhance dose flexibility. However, poor dispensing precision impedes its utilisation until appropriate compatibility between FDM hardware and materials at varying drug contents can be attained.

Fabrication of an osmotic 3D printed solid dosage form for controlled release of active pharmaceutical ingredients

In pharmaceutical formulations, pharmacokinetic behavior of the Active Pharmaceutical Ingredients (API's) is significantly affected by their dissolution profiles. In this project, we attempted to create personalized dosage forms with osmotic properties that exhibit different API release patterns via Fused Deposition Modelling (FDM) 3D printing. Specifically, cellulose acetate was employed to create an external shell of an osmotically active core containing Diltiazem (DIL) as model drug. By removing parts of the shell (upper surface, linear lateral segments) were created dosage forms that modify their shape at specific time frames under the effect of the gradually induced osmotic pressure. Hot-Melt Extrusion (HME) was employed to fabricate two different 3DP feeding filaments, for the creation of either the shell or the osmotic core (dual-extrusion printing). Printed formulations and filaments were characterized by means of (TGA, XRD, DSC) and inspected using microscopy (optical and electron). The mechanical properties of the filaments were assessed by means of micro- and macro mechanical testing, whereas micro-Computed Tomography (μCT) was employed to investigate the volumetric changes occurring during the hydration process. XRD indicated the amorphization of DIL inside HME filaments and printed dosage forms, whereas the incorporated NaCl (osmogen) retained its crystallinity. Mechanical properties' testing confirmed the printability of produced filaments. Dissolution tests revealed that all formulations exhibited sustained release differing at the initiation time of the API dissolution (0, 120 and 360 min for the three different formulations). Finally, μCT uncovered the key structural changes associated with distinct phases of the release profile. The above results demonstrate the successful utilization of an FDM 3D printer in order to create osmotic 3D printed formulations exhibiting sustained and/or delayed release, that can be easily personalized containing API doses corresponding to each patient's specific needs.

Embedded 3D Printing of Novel Bespoke Soft Dosage Form Concept for Pediatrics

Embedded three-dimensional printing (e-3DP) is an emerging method for additive manufacturing where semi-solid materials are extruded within a solidifying liquid matrix. Here, we present the first example of employing e-3DP in the pharmaceutical field and demonstrate the fabrication of bespoke chewable dosage forms with dual drug loading for potential use in pediatrics. Lego^TM-like chewable bricks made of edible soft material (gelatin-based matrix) were produced by directly extruding novel printing patterns of model drug ink (embedded phase) into a liquid gelatin-based matrix (embedding phase) at an elevated temperature (70 °C) to then solidify at room temperature. Dose titration of the two model drugs (paracetamol and ibuprofen) was possible by using specially designed printing patterns of the embedded phase to produce varying doses. A linearity [R² = 0.9804 (paracetamol) and 0.9976 (ibuprofen)] was achieved between percentage of completion of printing patterns and achieved doses using a multi-step method. The impact of embedded phase rheological behavior, the printing speed and the needle size of the embedded phase were examined. Owning to their appearance, modular nature, ease of personalizing dose and geometry, and tailoring and potential inclusion of various materials, this new dosage form concept holds a substantial promise for novel dosage forms in pediatrics.

Shaping the future: recent advances of 3D printing in drug delivery and healthcare

Introduction: Three-dimensional (3D) printing is a relatively new, rapid manufacturing technology that has found promising applications in the drug delivery and medical sectors. Arguably, never before has the healthcare industry experienced such a transformative technology. This review aims to discuss the state of the art of 3D printing technology in healthcare and drug delivery. Areas covered: The current and future applications of printing technologies within drug delivery and medicine have been discussed. The latest innovations in 3D printing of customized medical devices, drug-eluting implants, and printlets (3D-printed tablets) with a tailored dose, shape, size, and release characteristics have been covered. The review also covers the state of the art of 3D printing in healthcare (covering topics such as dentistry, surgical and bioprinting of patient-specific organs), as well as the potential of recent innovations, such as 4D printing, to shape the future of drug delivery and to improve treatment pathways for patients. Expert opinion: A future perspective is provided on the potential for 3D printing in healthcare, covering strategies to overcome the major barriers to integration that are faced today.

3D Printing of a Multi-Layered Polypill Containing Six Drugs Using a Novel Stereolithographic Method

Three-dimensional printing (3DP) has demonstrated great potential for multi-material fabrication because of its capability for printing bespoke and spatially separated material conformations. Such a concept could revolutionise the pharmaceutical industry, enabling the production of personalised, multi-layered drug products on demand. Here, we developed a novel stereolithographic (SLA) 3D printing method that, for the first time, can be used to fabricate multi-layer constructs (polypills) with variable drug content and/or shape. Using this technique, six drugs, including paracetamol, caffeine, naproxen, chloramphenicol, prednisolone and aspirin, were printed with different geometries and material compositions. Drug distribution was visualised using Raman microscopy, which showed that whilst separate layers were successfully printed, several of the drugs diffused across the layers depending on their amorphous or crystalline phase. The printed constructs demonstrated excellent physical properties and the different material inclusions enabled distinct drug release profiles of the six actives within dissolution tests. For the first time, this paper demonstrates the feasibility of SLA printing as an innovative platform for multi-drug therapy production, facilitating a new era of personalised polypills.

Poly(vinyl alcohol) 3D printed tablets: The effect of polymer particle size on drug loading and process efficiency

Fused deposition modeling by 3D-printing is a rapid technique for the production of personalized drug dosage forms. One of the most delicate step of the whole process is the drug loading onto the thermoplastic polymer to obtain the drug-loaded filament used as feedstock for 3D FDM printers. With the aim of improving the drug loading, a systematic study on the influence of polymer size distribution on the quantity of drug able to adhere onto the polymer surface was conducted. Several solid mixtures were prepared, using five PVA batches (4000-5000 µm, 1000-2000 µm, 600-1000 µm, 250-600 µm, <250 µm) and Ciprofloxacin hydrochloride as active compound in different ratios. Operative specifics and printer's parameters were tuned for an optimal print of drug-loaded filaments into the desired dosage forms, i.e. cylindrical printlets, fully characterized in terms of homogeneity, process efficiency, physical properties, drug content and release kinetics. The PVA particle size affected the polymer ability to form homogeneous mixture with the drug and the efficiency of the extrusion process. In particular, finest PVA batches showed better processability and reduced the drug loss during the drug/polymer mixing and the extrusion process. Drug-loaded filaments with different drug concentrations were successfully printed and the obtained printlets dissolution profiles were almost superimposable, taking an important step for the future application of 3D-printing manufacturing process to obtain personalized galenic formulations.