Temperature and solvent facilitated extrusion based 3D printing for pharmaceuticals

Evaluation of Printability of PVA-Based Tablets from Powder and Assessment of Critical Rheological Parameters

Fused deposition modeling (FDM) is a rather new technology in the production of personalized dosage forms. The melting and printing of polymer-active pharmaceutical ingredient (API)-mixtures can be used to produce oral dosage forms with different dosage as well as release behavior. This process is utilized to increase the bioavailability of pharmaceutically relevant active ingredients that are poorly soluble in physiological medium by transforming them into solid amorphous dispersions (ASD). The release from such ASDs is expected to be faster and higher compared to the raw materials and thus enhance bioavailability. Printing directly from powder while forming ASDs from loperamide in Polyvinylalcohol was realized. Different techniques such as a change in infill and the incorporation of sorbitol as a plastisizer to change release patterns as well as a non-destructive way for the determination of API distribution were shown. By measuring the melt viscosities of the mixtures printed, a rheological model for the printer used is proposed.

A Bibliometric Analysis of 3D Printing in Personalized Medicine Research from 2012 to 2022

In recent years, the 3D printing of personalized drug formulations has attracted the attention of medical practitioners and academics. However, there is a lack of data-based analyses on the hotspots and trends of research in this field. Therefore, in this study, we performed a bibliometric analysis to summarize the 3D printing research in the field of personalized drug formulation from 2012 to 2022. This study was based on the Web of Science Core Collection Database, and a total of 442 eligible publications were screened. Using VOSviewer and online websites for bibliometric analysis and scientific mapping, it was observed that annual publications have shown a significant growth trend over the last decade. The United Kingdom and the United States, which account for 45.5% of the total number of publications, are the main drivers of this field. The International Journal of Pharmaceutics and University College London are the most prolific and cited journals and institutions. The researchers with the most contributions are Basit, Abdul W. and Goyanes Alvaro. The keyword analysis concluded that the current research hotspots are "drug release" and "drug dosage forms". In conclusion, 3D printing has broad application prospects in the field of personalized drugs, which will bring the pharmaceutical industry into a new era of innovation.

3D printed mucoadhesive orodispersible films manufactured by direct powder extrusion for personalized clobetasol propionate based paediatric therapies

The aim of this work is the development and production by Direct Powder Extrusion (DPE) 3D printing technique of novel oral mucoadhesive films delivering Clobetasol propionate (CBS), useful in paediatric treatment of Oral Lichen Planus (OLP), a rare chronic disease. The DPE 3D printing of these dosage forms can allow the reduction of frequency regimen, the therapy personalization, and reduction of oral cavity administration discomfort. To obtain suitable mucoadhesive films, different polymeric materials, namely hydroxypropylmethylcellulose or polyethylene oxide blended with chitosan (CS), were tested and hydroxypropyl-β-cyclodextrin was added to increase the CBS solubility. The formulations were tested in terms of mechanical, physico-chemical, and in vitro biopharmaceutical properties. The film showed a tenacious structure, with drug chemical-physical characteristics enhancement due to its partial amorphization during the printing stage and owing to cyclodextrins multicomponent complex formation. The presence of CS enhanced the mucoadhesive properties leading to a significant increase of drug exposure time on the mucosa. Finally, the printed films permeation and retention studies through porcine mucosae showed a marked retention of the drug inside the epithelium, avoiding drug systemic absorption. Therefore, DPE-printed films could represent a suitable technique for the preparation of mucoadhesive film potentially usable for paediatric therapy including OLP.

Towards Point-of-Care Manufacturing and Analysis of Immediate-Release 3D Printed Hydrocortisone Tablets for The Treatment of Congenital Adrenal Hyperplasia

Hydrocortisone (HC) is the preferred drug in children with congenital adrenal hyperplasia due to its lower potency as well as fewer reports of side effects. Fused deposition modelling (FDM) 3D printing holds the potential to produce low-cost personalised doses for children at the point of care. However, the compatibility of the thermal process to produce immediate-release bespoke tablets for this thermally labile active is yet to be established. This work aims to develop immediate-release HC tablets using FDM 3D printing and assess drug contents as a critical quality attribute (CQA) using a compact, low-cost near-infrared (NIR) spectroscopy as a process analytical technology (PAT). The FDM 3D printing temperature (140 °C) and drug concentration in the filament (10%-15% w/w) were critical parameters to meet the compendial criteria for drug contents and impurities. Using a compact low-cost NIR spectral device over a wavelength of 900-1700 nm, the drug contents of 3D printed tablets were assessed. Partial least squares (PLS) regression was used to develop individual calibration models to detect HC content in 3D printed tablets of lower drug contents, small caplet design, and relatively complex formula. The models demonstrated the ability to predict HC concentrations over a wide concentration range (0-15% w/w), which was confirmed by HPLC as a reference method. Ultimately, the capability of the NIR model had preceding dose verification performance on HC tablets, with linearity (R² = 0.981) and accuracy (RMSECV = 0.46%). In the future, the integration of 3DP technology with non-destructive PAT techniques will accelerate the adoption of on-demand, individualised dosing in a clinical setting.

Hybrid Manufacturing of Oral Solid Dosage Forms via Overprinting of Injection-Molded Tablet Substrates

Since 3D printing allows for patient-specific dosage forms, it has become a major focus in pharmaceutical research. However, it is difficult to scale up drug product manufacturing. Injection molding has been used in conjunction with hot-melt extrusion to mass produce drug products, but making tailored solid dosage forms with this technology is neither cost-effective nor simple. This study explored the use of a combination of fused filament fabrication and injection molding to create patient-specific solid dosage forms. A tablet fixation and location template was used to overprint directly on injection-molded tablet bases, and theophylline was combined with polycaprolactone and Kollidon^® VA64 via hot-melt extrusion to produce the filament. Dynamic mechanical analysis was used to evaluate the brittleness of the filament, and differential scanning calorimetry was used to analyze the thermal results. The results showed that theophylline had a flow promoting effect on the polymer blend and that overprinted tablets were manufactured faster than 3D-printed tablets. Drug release studies also showed that overprinted tablets released faster than injection-molded tablets. This method demonstrates the potential of hybrid manufacturing for the pharmaceutical industry as a means of bridging the gap between personalized dosage forms and mass production.

Immediate release 3D printed oral dosage forms: How different polymers have been explored to reach suitable drug release behaviour

Three-dimensional (3D) printing has been gaining attention as a new technological approach to obtain immediate release (IR) dosage forms. The versatility conferred by 3D printing techniques arises from the suitability of using different polymeric materials in the production of solids with different porosities, geometries, sizes, and infill patterns. The appropriate choice of polymer can facilitate in reaching IR specifications and afford other specific properties to 3D printed solid dosage forms. This review aims to provide an overview of the polymers that have been employed in the development of IR 3D printed dosage forms, mainly considering their in vitro drug release behaviour. The physicochemical and mechanical properties of the IR 3D printed dosage forms will also be discussed, together with the manufacturing process strategies. Up to now, methacrylic polymers, cellulosic polymers, vinyl derivatives, glycols and different polymeric blends have been explored to produce IR 3D printed dosage forms. Their effects on drug release profiles are critically discussed here, giving a complete overview to drive formulators towards a rational choice of polymeric material and thus contributing to future studies in 3D printing of pharmaceuticals.

Compounding Tailored Veterinary Chewable Tablets Close to the Point-of-Care by Means of 3D Printing

Certain patient populations receive insufficient medicinal treatment due to a lack of commercially available products. The number of approved veterinary products is limited, making animals a patient population with suboptimal medicinal treatments available. To answer to this unmet need, compounding and off-label use of human-marketed products are practiced. Both of which have a significant risk of preparation errors. Hence, there is a dire demand to find and implement a more automated approach to the accurate, precise, and rapid production of veterinary dosage forms close to the point-of-care. This study aimed to assess the use of semi-solid extrusion-based 3D printing for the preparation of tailored doses of theophylline in the form of a chewable dosage form suitable for veterinary use. This study proved that semi-solid extrusion-based 3D printing could successfully be utilized to manufacture pet-friendly, chewable theophylline-loaded tablets. The prepared dosage forms showed a high correlation (R² = 0.9973) between the designed size and obtained drug amount and met the USP and Ph. Eur. content uniformity criteria. Furthermore, the stability study showed the dosage form being stable and able to be used for up to three months after printing.

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.

Compatibility and stability studies involving polymers used in fused deposition modeling 3D printing of medicines

One of the challenges in developing three-dimensional printed medicines is related to their stability due to the manufacturing conditions involving high temperatures. This work proposed a new protocol for preformulation studies simulating thermal processing and aging of the printed medicines, tested regarding their morphology and thermal, crystallographic, and spectroscopic profiles. Generally, despite the strong drug-polymer interactions observed, the chemical stability of the model drugs was preserved under such conditions. In fact, in the metoprolol and Soluplus® composition, the drug's solubilization in the polymer produced a delay in the drug decomposition, suggesting a protective effect of the matrix. Paracetamol and polyvinyl alcohol mixture, in turn, showed unmistakable signs of thermal instability and chemical decomposition, in addition to physical changes. In the presented context, establishing protocols that simulate processing and storage conditions may be decisive for obtaining stable pharmaceutical dosage forms using three-dimensional printing technology.

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Preformulation protocol was proposed to guide the development of 3D-printed medicines.

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Drug models were able to support thermal processing equivalent to FDM/3D printing.

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Soluplus showed a protective effect for metoprolol after double heating and aging.

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Paracetamol and PVA mixture demonstrated incompatibility under heating processing.

Opportunities and challenges of three-dimensional printing technology in pharmaceutical formulation development

Three-dimensional printing is a technology that prints the products layer-by-layer, in which materials are deposited according to the digital model designed by computer aided design (CAD) software. This technology has competitive advantages regarding product design complexity, product personalization, and on-demand manufacturing. The emergence of 3D technology provides innovative strategies and new ways to develop novel drug delivery systems. This review summarizes the application of 3D printing technologies in the pharmaceutical field, with an emphasis on the advantages of 3D printing technologies for achieving rapid drug delivery, personalized drug delivery, compound drug delivery and customized drug delivery. In addition, this article illustrates the limitations and challenges of 3D printing technologies in the field of pharmaceutical formulation development.

Translating 3D printed pharmaceuticals: From hype to real-world clinical applications

Three-dimensional (3D) printing is a revolutionary technology that is disrupting pharmaceutical development by enabling the production of personalised printlets (3D printed drug products) on demand. By creating small batches of dose flexible medicines, this versatile technology offers significant advantages for clinical practice and drug development, namely the ability to personalise medicines to individual patient needs, as well as expedite drug development timelines within preclinical studies through to first-in-human (FIH) and Phase I/II clinical trials. Despite the widely demonstrated benefits of 3D printing pharmaceuticals, the clinical potential of the technology is yet to be realised. In this timely review, we provide an overview of the latest cutting-edge investigations in 3D printing pharmaceuticals in the pre-clinical and clinical arena and offer a forward-looking approach towards strategies to further aid the translation of 3D printing into the clinic.

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.

Polymeric drug delivery systems by additive manufacturing

Additive manufacturing (AM) is gaining interests in drug delivery applications, offering innovative opportunities for the design and development of systems with complex geometry and programmed controlled release profile. In addition, polymer-based drug delivery systems can improve drug safety, efficacy, patient compliance, and are the key materials in AM. Therefore, combining AM and polymers can be beneficial to overcome the existing limitations in the development of controlled release drug delivery systems. Considering these advantages, here we are focusing on the recent developments in the field of polymeric drug delivery systems prepared by AM. This review provides a comprehensive overview on a holistic polymer-AM perspective for drug delivery systems with discussion on the materials, properties, design and fabrication techniques and the mechanisms used to achieve a controlled release system. The current challenges and future perspectives for personalized medicine and clinical use of these systems are also briefly discussed.

Versatility on demand - The case for semi-solid micro-extrusion in pharmaceutics

Since additive manufacturing of pharmaceuticals has been introduced as viable method to produce individualized drug delivery systems with complex geometries and release profiles, semi-solid micro-extrusion has shown to be uniquely beneficial. Easy incorporation of actives, room-temperature processability and avoidance of cross-contamination by using disposables are some of the advantages that led many researchers to focus their work on this technology in the last few years. First acceptability and in-vivo studies have brought it closer towards implementation in decentralized settings. This review covers recently established process models in light of viscosity and printability discussions to help develop high quality printed medicines. Quality defining formulation and process parameters to characterize the various developed dosage forms are presented before critically discussing the role of semi-solid micro-extrusion in the future of personalized drug delivery systems. Remaining challenges regarding regulatory guidance and quality assurance that pose the last hurdle for large scale and commercial manufacturing are addressed.

Synergistic application of twin-screw granulation and selective laser sintering 3D printing for the development of pharmaceutical dosage forms with enhanced dissolution rates and physical properties

This study demonstrated the first case of combining a novel continuous granulation technique with powder-bed fusion-based selective laser sintering (SLS) process to enhance the dissolution rate and physical properties of a poorly water-soluble drug. Selective laser sintering and binder jetting 3D printing processes have gained much attention in pharmaceutical dosage form manufacturing in recent times. These powder bed-based 3D printing platforms have been known to face printing and uniformity problems due to the inherent poor flow properties of the pharmaceutical physical mixtures. To address this issue a hot-melt extrusion-based versatile granulation process equipped with a process analytical technology (PAT) tool for the in-line monitoring of critical quality attributes (i.e., solid-state) of indomethacin was developed. The collected granules with enhanced flow properties were mixed with Kollidon® VA64 and a conductive excipient for efficient sintering. These mixtures were further characterized for their bulk properties observing an excellent flow and later subjected to an SLS-3D printing process. The physical mixtures, processed granules, and printed tablets were characterized using conventional as well as advanced solid-state characterizations. These characterizations revealed the amorphous nature of the drug in the processed granules and printed tablets. Further, the in vitro release testing of the tablets with produced granules as a reference standard depicted a notable dissolution advantage (100% drug released in 5 min at >pH 6.8) over the pure drug and the physical mixture. Our developed system known as DosePlus combines innovative continuous granulation and SLS-3D printing process which can potentially improve the physical properties of the bulk drug and formulations in comparison to when used in isolation. This process can further find application in continuous manufacturing of granules and additive manufacturing of pharmaceuticals to produce dosage forms with excellent uniformity and solubility advantage.

Can filaments be stored as a shelf-item for on-demand manufacturing of oral 3D printed tablets? An initial stability assessment

3D printing of oral solid dosage forms is a recently introduced approach for dose personalisation. Fused deposition modelling (FDM) is one of the promising and heavily researched 3D printing techniques in the pharmaceutical field. However, the successful application of this technique relies greatly on the mass manufacturing of physically and chemically stable filaments, that can be readily available as a shelf item to be 3D printed on-demand. In this work, the stability of methacrylate polymers (Eudragit EPO, RL, L100-55 and S100), hydroxypropyl cellulose (HPC SSL) and polyvinyl pyrrolidone (PVP)-based filaments over 6 months were investigated. Filaments manufactured by hot melt extrusion (HME) were stored at either 5 °C or 30 °C + 65 %RH with/without vacuuming. The effects of storage on their dimensions, visual appearance, thermal properties, and 'printability' were analysed. Theophylline content, as well as in vitro release from the 3D printed tablets were also investigated. The filaments were analysed before storage, then after 1, 3 and 6 months from the manufacturing date. Storing the filaments at these conditions had a significant effect on their physical properties, such as shape, dimensions, flexibility and hence compatibility with FDM 3D printing. In general, the methacrylate-based filaments were more physically stable and compatible with FDM 3D printing following storage. Owing to their hygroscopic nature, cellulose- and PVP-based filaments demonstrated a reduction in their glass transition temperature upon storage, leading to increased flexibility and incompatibility with FDM 3D printer. Theophylline contents was not significantly changed during the storage. This work provides preliminary data for the impact of polymer species on the long-term stability of filaments. In general, storage and packaging conditions have a major impact on the potential of on-demand manufacturing of 3D printed tablets using hot melt extruded filaments.

3D printed extended release tablets for once daily use: An in vitro and in vivo evaluation study for a personalized solid dosage form

Fused deposition modeling (FDM)-3D printing enables the manufacturing of dosage forms with personalized doses and controllable release profiles. Parkinson's disease is a neurodegenerative disorder that causes motor complications. In the treatment of the disease, the nonergot dopamine receptor agonist pramipexole is used in gradually increasing doses depending on patient's needs. Hence, there are various dosed commercial products of pramipexole and it is a suitable model drug for the preparation of personalized-dose 3D printed dosage forms. In this study, we prepared extended release 3D tablets of pramipexole for once daily use in Parkinson's disease. Herein, 12 different 3D tablet formulations were prepared and in vitro characterizations were performed on these formulations. The formulations were compared with the marketed tablet and the optimum formulation was selected. The chosen formulation was prepared with commercially available doses of pramipexole and also with intermediate doses which are not available in the market to demonstrate the applicability of 3D printing in personalized dosing. Stability studies, which have innovative features for 3D tablets, were conducted in optimum 3D tablet formulation for 6 months at 25 °C/60% relative humidity (RH) and 40 °C/75% RH conditions. After oral administration of the optimum 3D tablets and the marketed tablets (in the same dose) to the rats, 24-hour plasma profiles were obtained and pharmacokinetic parameters were calculated. 3D tablets were successfully prepared in personalized doses and their properties were similar for almost all doses. The optimum 3D tablet formulation was found to be stable during the stability tests. 3D tablet and marketed tablet performed similar plasma profiles. The relative bioavailability of 3D tablet formulation was calculated as 107.6% compared with the marketed tablet. Briefly, in vitro and in vivo evaluations demonstrated that FDM-3D printing is a promising technology for the development of personalized dosage forms with extended release property and comparable to conventional ones.

3D printing of gummy drug formulations composed of gelatin and an HPMC-based hydrogel for pediatric use

The 3D printing of drug formulations is a promising method for preparing tailored medicines following the approval of 3D printed tablets by the US FDA in 2015. Appropriate dosage forms for pediatric patients are deficient because drugs have been developed for mainly adult patients. Here, we fabricated gummy drug formulations for pediatric patients using a 3D bioprinter compatible with semi-solid materials such as hydrogels and pastes. The gummy drug formulations were composed of gelatin, HPMC, reduced syrup, water and the antiepileptic drug lamotrigine. The formulations were extruded from the nozzle of the 3D bioprinter under air pressure and laminated from the bottom in a layer-by-layer process. The incorporation of HPMC aided smooth printing at room temperature, and gelatin and HPMC affected the viscosity of the drug formulation and the printability of the formulations. The strength of the gummy formulations was remarkably influenced by the gelatin concentration. Dissolution tests showed 85% drug release within 15 min from most formulations. The results suggest that 3D printing is an effective method for preparing gummy drug formulations with various shapes in different colors, and that the methodology may improve drug adherence of pediatric patients in future clinical settings.