Water-based 3D inkjet printing of an oral pharmaceutical dosage form

Inkjet Printing of Pharmaceuticals

Inkjet printing (IJP) is an additive manufacturing process that selectively deposits ink materials, layer-by-layer, to create 3D objects or 2D patterns with precise control over their structure and composition. This technology has emerged as an attractive and versatile approach to address the ever-evolving demands of personalized medicine in the healthcare industry. Although originally developed for nonhealthcare applications, IJP harnesses the potential of pharma-inks, which are meticulously formulated inks containing drugs and pharmaceutical excipients. Delving into the formulation and components of pharma-inks, the key to precise and adaptable material deposition enabled by IJP is unraveled. The review extends its focus to substrate materials, including paper, films, foams, lenses, and 3D-printed materials, showcasing their diverse advantages, while exploring a wide spectrum of therapeutic applications. Additionally, the potential benefits of hardware and software improvements, along with artificial intelligence integration, are discussed to enhance IJP's precision and efficiency. Embracing these advancements, IJP holds immense potential to reshape traditional medicine manufacturing processes, ushering in an era of medical precision. However, further exploration and optimization are needed to fully utilize IJP's healthcare capabilities. As researchers push the boundaries of IJP, the vision of patient-specific treatment is on the horizon of becoming a tangible reality.

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 screen printing technology enables fabrication of oral drug dosage forms with freely tailorable release profiles

3D printing offers new opportunities to customize oral dosage forms of pharmaceuticals for different patient populations, improving patient safety, care, and compliance. Although several notable 3D print technologies have been developed, such as inkjet printing, powder-based printing, selective laser sintering (SLS) printing, and fused deposition modelling (FDM), among others, their capacity is often limited by the number of printing heads. 3D screen-printing (3DSP) is based on a classic flatbed screen printing that is widely used in industrial applications for technical applications. 3DSP can build up thousands of units per screen simultaneously, enabling mass customization of pharmaceuticals. Here, we use 3DSP to investigate two novel paste formulations: immediate-release (IR) and extended-release (ER) using Paracetamol (acetaminophen) as the active pharmaceutical ingredient (API). Both disk-shaped and donut-shaped tablets were fabricated using one or both pastes to design drug delivery systems (DDS) with tailored API release profiles. The size and mass of the produced tablets demonstrated high uniformity. Characterization of the tablets physical properties, such as breaking force (25-39 N) and friability (0.002-0.237%), adhering to Ph. Eur (10th edition). Finally, drug release tests with a phosphate buffer at pH 5.8 showed Paracetamol release depended on the IR- and ER paste materials and their respective compartment size of the composite DDS, which can be readily varied using 3DSP. This work further demonstrates the potential of 3DSP to manufacture complex oral dosage forms exhibiting custom release functionalities for mass production.

Designing Lignin-Based Biomaterials as Carriers of Bioactive Molecules

There is a need to develop circular and sustainable economies by utilizing sustainable, green, and renewable resources in high-tech industrial fields especially in the pharmaceutical industry. In the last decade, many derivatives of food and agricultural waste have gained considerable attention due to their abundance, renewability, biocompatibility, environmental amiability, and remarkable biological features. Particularly, lignin, which has been used as a low-grade burning fuel in the past, recently attracted a lot of attention for biomedical applications because of its antioxidant, anti-UV, and antimicrobial properties. Moreover, lignin has abundant phenolic, aliphatic hydroxyl groups, and other chemically reactive sites, making it a desirable biomaterial for drug delivery applications. In this review, we provide an overview of designing different forms of lignin-based biomaterials, including hydrogels, cryogels, electrospun scaffolds, and three-dimensional (3D) printed structures and how they have been used for bioactive compound delivery. We highlight various design criteria and parameters that influence the properties of each type of lignin-based biomaterial and corelate them to various drug delivery applications. In addition, we provide a critical analysis, including the advantages and challenges encountered by each biomaterial fabrication strategy. Finally, we highlight the prospects and future directions associated with the application of lignin-based biomaterials in the pharmaceutical field. We expect that this review will cover the most recent and important developments in this field and serve as a steppingstone for the next generation of pharmaceutical research.

3D printing for personalised medicines: implications for policy and practice

The current healthcare dynamic has shifted from one-size-fits-all to patient-centred care, with our increased understanding of pharmacokinetics and pharmacogenomics demanding a switch to more individualised therapies. As the pharmaceutical industry remains yet to succumb to the push of a technological paradigm shift, pharmacists lack the means to provide completely personalised medicine (PM) to their patients in a safe, affordable, and widely accessible manner. As additive manufacturing technology has already established its strength in producing pharmaceutical formulations, it is necessary to next consider methods by which this technology can create PM accessible from pharmacies. In this article, we reviewed the limitations of current pharmaceutical manufacturing methods for PMs, three-dimensional (3D) printing techniques that are most beneficial for PMs, implications of bringing this technology into pharmacy practice, and implications for policy surrounding 3D printing techniques in the manufacturing of PMs.

Recent Advances in the Applications of Additive Manufacturing (3D Printing) in Drug Delivery: A Comprehensive Review

There has been a tremendous increase in the investigations of three-dimensional (3D) printing for biomedical and pharmaceutical applications, and drug delivery in particular, ever since the US FDA approved the first 3D printed medicine, SPRITAM® (levetiracetam) in 2015. Three-dimensional printing, also known as additive manufacturing, involves various manufacturing techniques like fused-deposition modeling, 3D inkjet, stereolithography, direct powder extrusion, and selective laser sintering, among other 3D printing techniques, which are based on the digitally controlled layer-by-layer deposition of materials to form various geometries of printlets. In contrast to conventional manufacturing methods, 3D printing technologies provide the unique and important opportunity for the fabrication of personalized dosage forms, which is an important aspect in addressing diverse patient medical needs. There is however the need to speed up the use of 3D printing in the biopharmaceutical industry and clinical settings, and this can be made possible through the integration of modern technologies like artificial intelligence, machine learning, and Internet of Things, into additive manufacturing. This will lead to less human involvement and expertise, independent, streamlined, and intelligent production of personalized medicines. Four-dimensional (4D) printing is another important additive manufacturing technique similar to 3D printing, but adds a 4th dimension defined as time, to the printing. This paper aims to give a detailed review of the applications and principles of operation of various 3D printing technologies in drug delivery, and the materials used in 3D printing, and highlight the challenges and opportunities of additive manufacturing, while introducing the concept of 4D printing and its pharmaceutical applications.

4D prints of flexible dosage forms using thermoplastic polyurethane with hybrid shape memory effect

Thermoplastic polyurethanes are versatile materials due to their flexible and elastic properties. In research, medicine, and pharmacy, they are used in dosage forms, implants or as components of medical devices. To gain a deeper understanding of the influences on unfolding or expanding dosage forms, in this publication, 3D printing was used to produce differently shaped and foldable objects from various technical thermoplastic polyurethane filaments. The shape memory behaviour of the dosage forms was exploited to fold and package them in water-soluble hard gelatin capsules. The unfolding time and dimensional recovery of the 3D printed dosage forms were investigated as a function of material properties and shape. As an example, for the use of flexible dosage forms, 3D models have been designed so that their unfolded size is suitable for possible gastric retention. Depending on the shape and material, different unfolding behaviours could be shown. Over a storage period of 60 days, a time related stress on the 4D printed objects was evaluated, which possibly affects the unfolding process. The results of this work aim to be used to evaluate the behaviour of 3D printed unfolding and expanding dosage forms and how they may be suitable for the development of innovative sustained drug delivery concepts or medicinal devices. The basic principle of a hybrid shape memory effect used here could possibly be applied to other drug delivery strategies besides gastric retention.

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.

Three-Dimensional (3D) Printing in Cancer Therapy and Diagnostics: Current Status and Future Perspectives

Three-dimensional (3D) printing is a technique where the products are printed layer-by-layer via a series of cross-sectional slices with the exact deposition of different cell types and biomaterials based on computer-aided design software. Three-dimensional printing can be divided into several approaches, such as extrusion-based printing, laser-induced forward transfer-based printing systems, and so on. Bio-ink is a crucial tool necessary for the fabrication of the 3D construct of living tissue in order to mimic the native tissue/cells using 3D printing technology. The formation of 3D software helps in the development of novel drug delivery systems with drug screening potential, as well as 3D constructs of tumor models. Additionally, several complex structures of inner tissues like stroma and channels of different sizes are printed through 3D printing techniques. Three-dimensional printing technology could also be used to develop therapy training simulators for educational purposes so that learners can practice complex surgical procedures. The fabrication of implantable medical devices using 3D printing technology with less risk of infections is receiving increased attention recently. A Cancer-on-a-chip is a microfluidic device that recreates tumor physiology and allows for a continuous supply of nutrients or therapeutic compounds. In this review, based on the recent literature, we have discussed various printing methods for 3D printing and types of bio-inks, and provided information on how 3D printing plays a crucial role in cancer management.

3D Printing in Solid Dosage Forms and Organ-on-Chip Applications

3D printing (3DP) can serve not only as an excellent platform for producing solid dosage forms tailored to individualized dosing regimens but can also be used as a tool for creating a suitable 3D model for drug screening, sensing, testing and organ-on-chip applications. Several new technologies have been developed to convert the conventional dosing regimen into personalized medicine for the past decade. With the approval of Spritam, the first pharmaceutical formulation produced by 3DP technology, this technology has caught the attention of pharmaceutical researchers worldwide. Consistent efforts are being made to improvise the process and mitigate other shortcomings such as restricted excipient choice, time constraints, industrial production constraints, and overall cost. The objective of this review is to provide an overview of the 3DP process, its types, types of material used, and the pros and cons of each technique in the application of not only creating solid dosage forms but also producing a 3D model for sensing, testing, and screening of the substances. The application of producing a model for the biosensing and screening of drugs besides the creation of the drug itself, offers a complete loop of application for 3DP in pharmaceutics.

Printing Drugs onto Nails for Effective Treatment of Onychomycosis

Inkjet printing (IJP) is an emerging technology for the precision dosing of medicines. We report, for the first time, the printing of the antifungal drug terbinafine hydrochloride directly onto nails for the treatment of onychomycosis. A commercial cosmetic nail printer was modified by removing the ink from the cartridge and replacing it with an in-house prepared drug-loaded ink. The drug-loaded ink was designed so that it was comparable to the commercial ink for key printability properties. Linear drug dosing was shown by changing the lightness of the colour selected for printing (R² = 0.977) and by printing multiple times (R² = 0.989). The drug loads were measured for heart (271 µg), world (205 µg) and football (133 µg) shapes. A disc diffusion assay against Trpytophan rubrum showed inhibition of fungal growth with printed-on discs. In vitro testing with human nails showed substantial inhibition with printed-on nails. Hence, this is the first study to demonstrate the ability of a nail printer for drug delivery, thereby confirming its potential for onychomycosis treatment.

Drop-on-demand printing of personalised orodispersible films fabricated by precision micro-dispensing

Personalised orodispersible films (ODFs) manufactured at the point of care offer the possibility of adapting the dosing requirements for individual patients. Inkjet printing was extensively explored as a tool to produce personalised ODFs, but it is extensively limited to dispensing liquid with low viscosity and the interaction between ink and edible substrate complicates the fabrication process. In this study, we evaluated the feasibility of using a micro-dispensing (MD) jet system capable of accurately dispensing viscous liquid to fabricate substrate-free ODFs on-demand. The model inks containing hydroxypropyl methylcellulose (HPMC) and paracetamol were used to prepare personalised ODFs by expanding the film area. Cast films were used as the control sample to benchmark the mechanical properties, disintegration time, and dosing accuracy of MD printed ODFs. Both the cast and printed films showed smooth surface morphology without any bubbles. No significant difference was found in the disintegration time of the MD printed films compared to the cast films. High precision in dosing by MD printing was achieved. The dose of paracetamol had a linear correlation with the dimension of the printed films (R² = 0.995). The results provide clear evidence of the potential of MD printing to fabricate ODFs and the knowledge foundation of advancing MD printing to a point-of-care small-batch manufacturing technology of personalised ODFs.

Customisable Tablet Printing: The Development of Multimaterial Hot Melt Inkjet 3D Printing to Produce Complex and Personalised Dosage Forms

One of the most striking characteristics of 3D printing is its capability to produce multi-material objects with complex geometry. In pharmaceutics this translates to the possibility of dosage forms with multi-drug loading, tailored dosing and release. We have developed a novel dual material hot-melt inkjet 3D printing system which allows for precisely controlled multi-material solvent free inkjet printing. This reduces the need for time-consuming exchanges of printable inks and expensive post processing steps. With this printer, we show the potential for design of printed dosage forms for tailored drug release, including single and multi-material complex 3D patterns with defined localised drug loading where a drug-free ink is used as a release-retarding barrier. For this, we used Compritol HD5 ATO (matrix material) and Fenofibrate (model drug) to prepare both drug-free and drug-loaded inks with drug concentrations varying between 5% and 30% (w/w). The printed constructs demonstrated the required physical properties and displayed immediate, extended, delayed and pulsatile drug release depending on drug localisation inside of the printed formulations. For the first time, this paper demonstrates that a commonly used pharmaceutical lipid, Compritol HD5 ATO, can be printed via hot-melt inkjet printing as single ink material, or in combination with a drug, without the need for additional solvents. Concurrently, this paper demonstrates the capabilities of dual material hot-melt inkjet 3D printing system to produce multi-material personalised solid dosage forms.

An updated review on application of 3D printing in fabricating pharmaceutical dosage forms

The concept of "one size fits all" followed by the conventional healthcare system has drawbacks in providing precise pharmacotherapy due to variation in the pharmacokinetics of different patients leading to serious consequences such as side effects. In this regard, digital-based three-dimensional printing (3DP), which refers to fabricating 3D printed pharmaceutical dosage forms with variable geometry in a layer-by-layer fashion, has become one of the most powerful and innovative tools in fabricating "personalized medicine" to cater to the need of therapeutic benefits for patients to the maximum extent. This is achieved due to the tremendous potential of 3DP in tailoring various drug delivery systems (DDS) in terms of size, shape, drug loading, and drug release. In addition, 3DP has a huge impact on special populations including pediatrics, geriatrics, and pregnant women with unique or frequently changing medical needs. The areas covered in the present article are as follows: (i) the difference between traditional and 3DP manufacturing tool, (ii) the basic processing steps involved in 3DP, (iii) common 3DP methods with their pros and cons, (iv) various DDS fabricated by 3DP till date with discussing few research studies in each class of DDS, (v) the drug loading principles into 3D printed dosage forms, and (vi) regulatory compliance.

Polymers in pharmaceutical additive manufacturing: A balancing act between printability and product performance

Materials and manufacturing processes share a common purpose of enabling the pharmaceutical product to perform as intended. This review on the role of polymeric materials in additive manufacturing of oral dosage forms, focuses on the interface between the polymer and key stages of the additive manufacturing process, which determine printability. By systematically clarifying and comparing polymer functional roles and properties for a variety of AM technologies, together with current and emerging techniques to characterize these properties, suggestions are provided to stimulate the use of readily available and sometimes underutilized pharmaceutical polymers in additive manufacturing. We point to emerging characterization techniques and digital tools, which can be harnessed to manage existing trade-offs between the role of polymers in printer compatibility versus product performance. In a rapidly evolving technological space, this serves to trigger the continued development of 3D printers to suit a broader variety of polymers for widespread applications of pharmaceutical additive manufacturing.

Harnessing artificial intelligence for the next generation of 3D printed medicines

Artificial intelligence (AI) is redefining how we exist in the world. In almost every sector of society, AI is performing tasks with super-human speed and intellect; from the prediction of stock market trends to driverless vehicles, diagnosis of disease, and robotic surgery. Despite this growing success, the pharmaceutical field is yet to truly harness AI. Development and manufacture of medicines remains largely in a 'one size fits all' paradigm, in which mass-produced, identical formulations are expected to meet individual patient needs. Recently, 3D printing (3DP) has illuminated a path for on-demand production of fully customisable medicines. Due to its flexibility, pharmaceutical 3DP presents innumerable options during formulation development that generally require expert navigation. Leveraging AI within pharmaceutical 3DP removes the need for human expertise, as optimal process parameters can be accurately predicted by machine learning. AI can also be incorporated into a pharmaceutical 3DP 'Internet of Things', moving the personalised production of medicines into an intelligent, streamlined, and autonomous pipeline. Supportive infrastructure, such as The Cloud and blockchain, will also play a vital role. Crucially, these technologies will expedite the use of pharmaceutical 3DP in clinical settings and drive the global movement towards personalised medicine and Industry 4.0.

Machine learning predicts 3D printing performance of over 900 drug delivery systems

Three-dimensional printing (3DP) is a transformative technology that is advancing pharmaceutical research by producing personalized drug products. However, advances made via 3DP have been slow due to the lengthy trial-and-error approach in optimization. Artificial intelligence (AI) is a technology that could revolutionize pharmaceutical 3DP through analyzing large datasets. Herein, literature-mined data for developing AI machine learning (ML) models was used to predict key aspects of the 3DP formulation pipeline and in vitro dissolution properties. A total of 968 formulations were mined and assessed from 114 articles. The ML techniques explored were able to learn and provide accuracies as high as 93% for values in the filament hot melt extrusion process. In addition, ML algorithms were able to use data from the composition of the formulations with additional input features to predict the drug release of 3D printed medicines. The best prediction was obtained by an artificial neural network that was able to predict drug release times of a formulation with a mean error of ±24.29 min. In addition, the most important variables were revealed, which could be leveraged in formulation development. Thus, it was concluded that ML proved to be a suitable approach to modelling the 3D printing workflow.

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.

Long-acting implantable dosage forms containing paliperidone palmitate obtained by 3D printing

In this work, the versatility of pressure extrusion-based printing (PEBP) was used as 3D printing process to create long-acting implantable dosage forms. Different release profiles were achieved based on the drug concentration, the way of preparation and the design of the final implants. Polycaprolactone (PCL) was used as the polymer to sustain the release of the loaded drug. Paliperidone palmitate (PP), a BCS Class II drug, used in the treatment of schizophrenia, was used as the model drug. Two PP concentrations (e.g. 5 and 10% w/w) as well as two methods of preparation before the 3D printing process, mortar and pestle and cryogenic milling, were evaluated. The amorphous state of PP was obtained by using cryogenic milling and it was maintained after printing. Two designs were printed by PEBP, a ring and a disk, to evaluate their impact on the release profile of PP. During the in vitro dissolution tests, the implant design, the amount of PP, as well as the crystalline or amorphous state of PP have shown to influence the drug release profile. During the successive steps of preparation of the long-acting implants, blends and raw materials were characterized by DSC and XRD.

Image Analysis: A Versatile Tool in the Manufacturing and Quality Control of Pharmaceutical Dosage Forms

In pharmaceutical sciences, visual inspection is one of the oldest methods used for description in pharmacopeias and is still an important part of the characterization and qualification of active ingredients, excipients, and dosage forms. With the development of technology, it is now also possible to take images of various pharmaceutical dosage forms with different imaging methods in a size range that is hardly visible or completely invisible to the human eye. By analyzing high-quality designs, physicochemical processes can be understood, and the results can be used even in the optimization of the composition of the dosage form and in the development of its production. The present study aims to show some of the countless ways image analysis can be used in the manufacturing and quality assessment of different dosage forms. This summary also includes measurements and an evaluation of, amongst others, a less studied dosage form, medicated foams.

Practicality of 3D Printed Personalized Medicines in Therapeutics

Technological advances in science over the past century have paved the way for remedial treatment outcomes in various diseases. Pharmacogenomic predispositions, the emergence of multidrug resistance, medication and formulation errors contribute significantly to patient mortality. The concept of "personalized" or "precision" medicines provides a window to addressing these issues and hence reducing mortality. The emergence of three-dimensional printing of medicines over the past decades has generated interests in therapeutics and dispensing, whereby the provisions of personalized medicines can be built within the framework of producing medicines at dispensaries or pharmacies. This plan is a good replacement of the fit-for-all modality in conventional therapeutics, where clinicians are constrained to prescribe pre-formulated dose units available on the market. However, three-dimension printing of personalized medicines faces several hurdles, but these are not insurmountable. In this review, we explore the relevance of personalized medicines in therapeutics and how three-dimensional printing makes a good fit in current gaps within conventional therapeutics in order to secure an effective implementation of personalized medicines. We also explore the deployment of three-dimensional printing of personalized medicines based on practical, legal and regulatory provisions.

3DP Printing of Oral Solid Formulations: A Systematic Review

Three-dimensional (3D) printing is a recent technology, which gives the possibility to manufacture personalised dosage forms and it has a broad range of applications. One of the most developed, it is the manufacture of oral solid dosage and the four 3DP techniques which have been more used for their manufacture are FDM, inkjet 3DP, SLA and SLS. This systematic review is carried out to statistically analyze the current 3DP techniques employed in manufacturing oral solid formulations and assess the recent trends of this new technology. The work has been organised into four steps, (1) screening of the articles, definition of the inclusion and exclusion criteria and classification of the articles in the two main groups (included/excluded); (2) quantification and characterisation of the included articles; (3) evaluation of the validity of data and data extraction process; (4) data analysis, discussion, and conclusion to define which technique offers the best properties to be applied in the manufacture of oral solid formulations. It has been observed that with SLS 3DP technique, all the characterisation tests required by the BP (drug content, drug dissolution profile, hardness, friability, disintegration time and uniformity of weight) have been performed in the majority of articles, except for the friability test. However, it is not possible to define which of the four 3DP techniques is the most suitable for the manufacture of oral solid formulations, because the selection is affected by different parameters, such as the type of formulation, the physical-mechanical properties to achieve. Moreover, each technique has its specific advantages and disadvantages, such as for FDM the biggest challenge is the degradation of the drug, due to high printing temperature process or for SLA is the toxicity of the carcinogenic risk of the photopolymerising material.

Inkjet printing of small molecules, biologics, and nanoparticles

During the last decades, inkjet printing has emerged as a novel technology and attracted the attention of the pharmaceutical industry, as a potential method for manufacturing personalized and customizable dosage forms to deliver drugs. Commonly, the desired drug is dissolved or dispersed within the ink and then dispensed in various dosage forms. Using this approach, several studies have been conducted to load hydrophilic or poorly water-soluble small molecules onto the surface of different solid substrates, including films, tablets, microneedles, and smart data-enriched edible pharmaceuticals, using two-dimensional and three-dimensional inkjet printing methods, with high dose accuracy and reproducibility. Furthermore, biological drugs, such as peptides, proteins, growth factors, and plasmids, have also been evaluated with positive results, eliciting the expected biological response; nonetheless, minor changes in the structure of these compounds with significant impaired activity cannot be dismissed. Another strategy using inkjet printing is to disperse drug-loaded nanoscale particles in the ink liquid, such as nanosuspension, nanocomplexes, or nanoparticles, which have been explored with promising results. Although these favorable outcomes, the proper selection of ink constituents and the inkjet printer, the correlation of printing cycles and effectively printed doses, the stability studies of drugs within the ink and the optimal analysis of samples before and after the printing process are the main challenges for inkjet printing, and therefore, this review analyzes these aspects to assess the body of current literature and help to guide future investigations on this field.

Innovative color jet 3D printing of levetiracetam personalized paediatric preparations

3D printing is a promising technology used in the fabrication of complex oral dosage delivery pharmaceuticals. This study first reports an innovative color jet 3D printing (CJ-3DP) technology to produce colorful cartoon levetiracetam pediatric preparations with high accuracy and reproducibility. For this study, the ideal printing ink consisted of 40% (v/v) isopropanol aqueous solution containing 0.05% (w/w) polyvinylpyrrolidone and 4% (w/w) glycerin, which was satisfied with scale-up of the production. The external and internal spatial structures of the tablets were designed to control the appearance and release, and cartoon tablets with admirable appearances and immediate release characteristics were printed. The dosage model showed a good linear relationship between the model volume and the tablet strength (r > 0.999), which proved the potential of personalized administration. The surface roughness indicated that the appearance of the CJ-3DP tablets was significantly better than the first listed 3D printed drug (Spritam^Ⓡ). Moreover, the scanning electron microscopy and porosity results further showed that the tablets have a structure of loose interior and tight exterior, which could ensure good mechanical properties and rapid dispersion characteristics simultaneously. In conclusion, the innovative CJ-3DP technology can be used to fabricate personalized pediatric preparations for improved compliance. Due to the stable formulation and fabrication process, this technology has the potential in scale-up production.

Applications of 3D printed bone tissue engineering scaffolds in the stem cell field

Due to traffic accidents, injuries, burns, congenital malformations and other reasons, a large number of patients with tissue or organ defects need urgent treatment every year. The shortage of donors, graft rejection and other problems cause a deficient supply for organ and tissue replacement, repair and regeneration of patients, so regenerative medicine came into being. Stem cell therapy plays an important role in the field of regenerative medicine, but it is difficult to fill large tissue defects by injection alone. The scientists combine three-dimensional (3D) printed bone tissue engineering scaffolds with stem cells to achieve the desired effect. These scaffolds can mimic the extracellular matrix (ECM), bone and cartilage, and eventually form functional tissues or organs by providing structural support and promoting attachment, proliferation and differentiation. This paper mainly discussed the applications of 3D printed bone tissue engineering scaffolds in stem cell regenerative medicine. The application examples of different 3D printing technologies and different raw materials are introduced and compared. Then we discuss the superiority of 3D printing technology over traditional methods, put forward some problems and limitations, and look forward to the future.

3D Printing as a Promising Tool in Personalized Medicine

Personalized medicine has the potential to revolutionize the healthcare sector, its goal being to tailor medication to a particular individual by taking into consideration the physiology, drug response, and genetic profile of that individual. There are many technologies emerging to cause this paradigm shift from the conventional "one size fits all" to personalized medicine, the major one being three-dimensional (3D) printing. 3D printing involves the establishment of a three-dimensional object, in a layer upon layer manner using various computer software. 3D printing can be used to construct a wide variety of pharmaceutical dosage forms varying in shape, release profile, and drug combination. The major technological platforms of 3D printing researched on in the pharmaceutical sector include inkjet printing, binder jetting, fused filament fabrication, selective laser sintering, stereolithography, and pressure-assisted microsyringe. A possible future application of this technology could be in a clinical setting, where prescriptions could be dispensed based on individual needs. This manuscript points out the various 3D printing technologies and their applications in research for fabricating pharmaceutical products, along with their pros and cons. It also presents its potential in personalized medicine by individualizing the dose, release profiles, and incorporating multiple drugs in a polypill. An insight on how it tends to various populations is also provided. An approach of how it can be used in a clinical setting is also highlighted. Also, various challenges faced are pointed out, which must be overcome for the success of this technology in personalized medicine.

Evaluation of exposure time and visible light irradiation in LCD 3D printing of ibuprofen extended release tablets

Liquid crystal display (LCD) 3D printing technology is one of the three currently available photocuring three-dimensional printing technologies. LCD 3D printers usually use wavelengths in the ultraviolent (UV) range. However, recently introduced light-emitting diodes (LED) projectors enable visible light-induced photopolymerization, which would have an advantage in terms of safety in drug production. The aim of this work was to investigate the feasibility of printing ibuprofen extended release tablets under visible light irradiation and to evaluate characteristics of printed tablets. Influences of exposure time and wavelengths (UV versus visible light) on characteristics of tablets were evaluated. Tablets were printed using 405 nm and 450 nm LED light. Visible light enabled significantly faster printing as well as better dimensions accuracy of printed tablets. It was noticed that printing under 450 nm LED resulted in slightly softer tablets compared to tablets printing with 405 nm LED. Extended ibuprofen release was obtained from all formulations. Exposure time did not have influence on drug release in formulations with low water content. However, in a formulation with higher water content, the exposure time had a pronounced effect on drug release (in eight hours of testing, differences were from 27% to 95%). Wavelength affected the release rate of ibuprofen. Tablets prepared using 450 nm LEDs released ibuprofen faster than tablets prepared with 405 nm LEDs. The main mechanism of ibuprofen release was diffusion, regardless of exposure time and wavelength. Characteristics of obtained tablets indicate that further optimization of this process is necessary, but this new printing process approach opens the possibility for novel wavelength consideration in order to obtain the safe printing process of tablets.

Inkjet Bioprinting of Biomaterials

The inkjet technique has the capability of generating droplets in the picoliter volume range, firing thousands of times in a few seconds and printing in the noncontact manner. Since its emergence, inkjet technology has been widely utilized in the publishing industry for printing of text and pictures. As the technology developed, its applications have been expanded from two-dimensional (2D) to three-dimensional (3D) and even used to fabricate components of electronic devices. At the end of the twentieth century, researchers were aware of the potential value of this technology in life sciences and tissue engineering because its picoliter-level printing unit is suitable for depositing biological components. Currently inkjet technology has been becoming a practical tool in modern medicine serving for drug development, scaffold building, and cell depositing. In this article, we first review the history, principles and different methods of developing this technology. Next, we focus on the recent achievements of inkjet printing in the biological field. Inkjet bioprinting of generic biomaterials, biomacromolecules, DNAs, and cells and their major applications are introduced in order of increasing complexity. The current limitations/challenges and corresponding solutions of this technology are also discussed. A new concept, biopixels, is put forward with a combination of the key characteristics of inkjet printing and basic biological units to bring a comprehensive view on inkjet-based bioprinting. Finally, a roadmap of the entire 3D bioprinting is depicted at the end of this review article, clearly demonstrating the past, present, and future of 3D bioprinting and our current progress in this field.

Hot-Melt 3D Extrusion for the Fabrication of Customizable Modified-Release Solid Dosage Forms

In this work, modified-release solid dosage forms were fabricated by adjusting geometrical properties of solid dosage forms through hot-melt 3D extrusion (3D HME). Using a 3D printer with air pressure driving HME system, solid dosage forms containing ibuprofen (IBF), polyvinyl pyrrolidone (PVP), and polyethylene glycol (PEG) were printed by simultaneous HME and 3D deposition. Printed solid dosage forms were evaluated for their physicochemical properties, dissolution rates, and floatable behavior. Results revealed that IBF content in the solid dosage form could be individualized by adjusting the volume of solid dosage form. IBF was dispersed as amorphous state with enhanced solubility and dissolution rate in a polymer solid dosage form matrix. Due to absence of a disintegrant, sustained release of IBF from printed solid dosage forms was observed in phosphate buffer at pH 6.8. The dissolution rate of IBF was dependent on geometric properties of the solid dosage form. The dissolution rate of IBF could be modified by merging two different geometries into one solid dosage form. In this study, the 3D HME process showed high reproducibility and accuracy for preparing dosage forms. API dosage and release profile were found to be customizable by modifying or combining 3D modeling.

3D Printing Technologies: Recent Development and Emerging Applications in Various Drug Delivery Systems

The 3D printing is considered as an emerging digitized technology that could act as a key driving factor for the future advancement and precise manufacturing of personalized dosage forms, regenerative medicine, prosthesis and implantable medical devices. Tailoring the size, shape and drug release profile from various drug delivery systems can be beneficial for special populations such as paediatrics, pregnant women and geriatrics with unique or changing medical needs. This review summarizes various types of 3D printing technologies with advantages and limitations particularly in the area of pharmaceutical research. The applications of 3D printing in tablets, films, liquids, gastroretentive, colon, transdermal and intrauterine drug delivery systems as well as medical devices have been briefed. Due to the novelty and distinct features, 3D printing has the inherent capacity to solve many formulation and drug delivery challenges, which are frequently associated with poorly aqueous soluble drugs. Recent approval of Spritam® and publication of USFDA technical guidance on additive manufacturing related to medical devices has led to an extensive research in various field of drug delivery systems and bioengineering. The 3D printing technology could be successfully implemented from pre-clinical phase to first-in-human trials as well as on-site production of customized formulation at the point of care having excellent dose flexibility. Advent of innovative 3D printing machineries with built-in flexibility and quality with the introduction of new regulatory guidelines would rapidly integrate and revolutionize conventional pharmaceutical manufacturing sector.

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.

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.