The Application of 3D Printing in the Formulation of Multilayered Fast Dissolving Oral Films

Reducing Temperature of Fused Deposition Modelling 3D Printing for Linalool Fast Dissolving Oral Films by Increasing Printer Nozzle Diameter

Oral thrush and throat infections can occur in a wide range of patients. Treatments are available; however, resistance to drugs is a major problem for treating oral and throat infections. Three-dimensional printing (3DP) of fast dissolving oral films (FDFs) of linalool oil may provide an alternative solution. Linalool oil FDFs were printed by fused deposition modelling across 1-18 % w/w linalool content range with nozzle diameters of 0.4 or 1 mm at the temperature range of 150 °C-185 °C. The FDFs were evaluated for physicochemical and mechanical properties. Increasing the printer nozzle diameter to 1 mm allowed reducing the printing temperature from 185 °C to 150 °C; consequently, more linalool was quantified in the films with improved content uniformity. The higher linalool content in the films increased the film disintegration time and mechanical strength. FDFs containing 10% w/w linalool showed clear antifungal activity against Candida albicans. Raman spectroscopy suggested linalool separation from excipients at higher temperature printing. Viscoelastic measurements indicated that to achieve printing; the elastic modulus of molten filament needed to be higher than the loss modulus at low angular frequencies. In conclusion, increasing the printing nozzle diameter may avoid loss of the active ingredient by reducing the temperature of the 3DP process.

3D Printing of Dietary Products for the Management of Inborn Errors of Intermediary Metabolism in Pediatric Populations

The incidence of Inborn Error of Intermediary Metabolism (IEiM) diseases may be low, yet collectively, they impact approximately 6-10% of the global population, primarily affecting children. Precise treatment doses and strict adherence to prescribed diet and pharmacological treatment regimens are imperative to avert metabolic disturbances in patients. However, the existing dietary and pharmacological products suffer from poor palatability, posing challenges to patient adherence. Furthermore, frequent dose adjustments contingent on age and drug blood levels further complicate treatment. Semi-solid extrusion (SSE) 3D printing technology is currently under assessment as a pioneering method for crafting customized chewable dosage forms, surmounting the primary limitations prevalent in present therapies. This method offers a spectrum of advantages, including the flexibility to tailor patient-specific doses, excipients, and organoleptic properties. These elements are pivotal in ensuring the treatment's efficacy, safety, and adherence. This comprehensive review presents the current landscape of available dietary products, diagnostic methods, therapeutic monitoring, and the latest advancements in SSE technology. It highlights the rationale underpinning their adoption while addressing regulatory aspects imperative for their seamless integration into clinical practice.

Unlocking the potential of 3D printed microfluidics for mass spectrometry analysis using liquid infused surfaces

Combining microfluidics with mass spectrometry (MS) analysis has great potential for enabling new analytical applications and simplifying existing MS workflows. The rapid development of 3D printing technology has enabled direct fabrication of microfluidic channels using consumer grade 3D printers, which holds great promise to facilitate the adoption of microfluidic devices by the MS community. However, photo polymerization-based 3D printed devices have an issue with chemical leeching, which can introduce contaminant molecules that may present as isobaric ions and/or severely suppress the ionization of target analytes when combined with MS analysis. Although extra cure and washing steps have alleviated the leeching issue, many such contaminant peaks can still show up in mass spectra. In this work, we report a simple surface modification strategy to isolate the chemical leachates from the channel solution thereby eliminating the contaminant peaks for MS analysis. The channel was prepared by fabricating a layer of polydimethylsiloxane graft followed by wetting the graft using silicone oil. The resulting liquid infused surface (LIS) showed significant reduction in contaminant peaks and improvement in the signal intensity of target analytes. The coating showed good stability after long-term usage (7 days) and long-term storage (∼6 months). Finally, the utility of the coating strategy was demonstrated by printing herringbone microfluidic mixers for studying fast reaction kinetics, which obtained comparable reaction rates to literature values. The effectiveness, simplicity, and stability of the present method will promote the adoption of 3D printed microdevices by the MS community.

Special Issue for "3D Printing of Drug Formulations"

Three-dimensional printing (3DP) is rapidly innovating the manufacturing process and provides opportunities that have never been seen before [...].

Fabrication of timed-release indomethacin core-shell tablets for chronotherapeutic drug delivery using dual nozzle Fused Deposition Modeling (FDM) 3D printing

In the present study, timed-release indomethacin tablets, releasing drug after predetermined lag times, were developed for the effective treatment of early morning stiffness in rheumatoid arthritis using two-nozzle fused deposition modeling (FDM) 3D printing with a Bowden extruder. The developed core-shell tablets consisted of a drug-containing core and release-regulating shell with different designed thicknesses (i.e., 0.4 mm, 0.6 mm, 0.8 mm). The filaments to fabricate cores and shells were prepared using hot-melt extrusion (HME), and different filament compositions were formulated for core tablets and screened for rapid release and printability. Eventually, the HPMCAS-based formulation comprised a core tablet enclosed by a shell of Affinisol™ 15LV, a swellable polymer. During 3D printing, one nozzle was dedicated to printing core tablets loaded with indomethacin, and the other nozzle was dedicated to printing shells, making a whole structure produced at once without inconvenient filament change and nozzle cleanout. The mechanical properties of filaments were compared using a texture analyzer. The core-shell tablets were characterized for dissolution profiles and physical attributes (e.g., dimension, friability, hardness). SEM image indicated a smooth and complete surface of the core-shell tablets. The tablets showed 4-8 hours of lag depending on the shell thicknesses and released most of the drugs in 3 hours, regardless of the shell thicknesses. The core-shell tablets showed high reproducibility but exhibited low dimensional accuracy in the shell thickness. This study explored the suitability of using two-nozzle FDM 3D printing with Bowden extrusion for producing personalized chronotherapeutic core-shell tablets and discussed possible challenges that needed to be considered for a successful printing process using this technology.

Advances in formulation and manufacturing strategies for the delivery of therapeutic proteins and peptides in orally disintegrating dosage forms

Therapeutic proteins and peptides (TPPs) are increasingly favoured above small drug molecules due to their high specificity to the site of action and reduced adverse effects resulting in increased use of these agents for medical treatments and therapies. Consequently, there is a need to formulate TPPs in dosage forms that are accessible and suitable for a wide range of patient groups as the use of TPPs becomes increasingly prevalent in healthcare settings worldwide. Orally disintegrating dosage forms (ODDF) are formulations that can ensure easy-to-administer medication to a wider patient population including paediatrics, geriatrics and people in low-resource countries. There are many challenges involved in developing suitable pharmaceutical strategies to protect TPPs during formulation and manufacturing, as well as storage, and maintenance of a cold-chain during transportation. This review will discuss advances being made in the research and development of pharmaceutical and manufacturing strategies used to incorporate various TPPs into ODDF systems.

Orodispersible Films-Current State of the Art, Limitations, Advances and Future Perspectives

Orodispersible Films (ODFs) are drug delivery systems manufactured with a wide range of methods on a big scale or for customized medicines and small-scale pharmacy. Both ODFs and their fabrication methods have certain limitations. Many pharmaceutical companies and academic research centers across the world cooperate in order to cope with these issues and also to find new formulations for a wide array of APIs what could make their work profitable for them and beneficial for patients as well. The number of pending patent applications and granted patents with their innovative approaches makes the progress in the manufacturing of ODFs unquestionable. The number of commercially available ODFs is still growing. However, some of them were discontinued and are no longer available on the markets. This review aims to summarize currently marketed ODFs and those withdrawn from sale and also provides an insight into recently published studies concerning orodispersible films, emphasizing of utilized APIs. The work also highlights the attempts of scientific communities to overcome ODF's manufacturing methods limitations.

The Use of Micro-Ribbons and Micro-Fibres in the Formulation of 3D Printed Fast Dissolving Oral Films

Three-dimensional printing (3DP) allows production of novel fast dissolving oral films (FDFs). However, mechanical properties of the films may not be desirable when certain excipients are used. This work investigated whether adding chitosan micro-ribbons or cellulose microfibres will achieve desired FDFs by fused deposition modelling 3DP. Filaments containing polyvinyl alcohol (PVA) and paracetamol as model drug were manufactured at 170 °C. At 130 °C, filaments containing polyvinylpyrrolidone (PVP) and paracetamol were also created. FDFs were printed with plain or mesh patterns at temperatures of 200 °C (PVA) or 180 °C (PVP). Both chitosan micro-ribbons and cellulose micro-fibres improved filament mechanical properties at 1% w/w concentration in terms of flexibility and stiffness. The filaments were not suitable for printing at higher concentrations of chitosan micro-ribbons and cellulose micro-fibres. Furthermore, mesh FDFs containing only 1% chitosan micro-ribbons disintegrated in distilled water within 40.33 ± 4.64 s, while mesh FDFs containing only 7% croscarmellose disintegrated in 55.33 ± 2.86 s, and croscarmellose containing films showed signs of excipient scorching for PVA polymer. Cellulose micro-fibres delayed disintegration of PVA mesh films to 108.66 ± 3.68 s at 1% w/w. In conclusion, only chitosan micro-ribbons created a network of hydrophilic channels within the films, which allowed faster disintegration time at considerably lower concentrations.

3D printing hybrid materials using fused deposition modelling for solid oral dosage forms

3D printing in the pharmaceutical and healthcare settings is expanding rapidly, such as the rapid prototyping of orthotics, dental retainers, drug-loaded implants, and pharmaceutical solid oral dosage forms. Through 3D printing, we have the capability to precisely control dose, release kinetics, and several aesthetic features of dosage forms such as colour, shape, and texture. Additionally, polypills can be created with combinations of medications in one solid dosage form at completely customisable strengths that would be extremely difficult to obtain commercially. As the technology and formulations developed through 3D printing are expanding, the development of new hybrid materials to obtain superior formulations are also gaining momentum. In this review we collate data on the importance of developing hybrid formulations of polymers, drugs and excipients necessary to produce reliable and high-quality 3D printed dosage forms with a special emphasis on fused deposition modelling (FDM). FDM technology is one of the most widely used forms of 3D printing and has demonstrated compatibility with unique polymer-based hybrids to allow for enhanced drug delivery, protection of thermolabile drugs, modifiable release kinetics, and more. The data collated covers different categories of hybrids as well as the methods used to fabricate them, and their respective effects on the properties of 3D printed solid oral dosage forms. Therefore, this review will provide an overview of upcoming and emerging trends in pharmaceutical 3D printing formulation compositions.

Fabrication of Hydroxypropyl Methylcellulose Orodispersible Film Loaded Mirtazapine Using a Syringe Extrusion 3D Printer

Depression is a mental illness causing a continuous negative feeling and loss of interest and affects physical and mental health. Mirtazapine (MTZ) is an effective medicine for treating depression, but patients lack compliance. However, transforming a pharmaceutical dosage form to an orodispersible film (ODF) could resolve this issue. This study aims to fabricate ODF-loading mirtazapine, using a syringe extrusion 3D printer, and compare its properties with the solvent-casting method. The ODFs were prepared by dissolving the mirtazapine in a hydroxypropyl methylcellulose E15 solution, and then fabricated by a 3D printer or casting. The 3D printing was accurate and precise in fabricating the ODFs. The SEM micrographs showed that the mirtazapine-printed ODF (3D-MTZ) was porous, with crystals of mirtazapine on the film’s surface. The 3D-MTZ exhibited better mechanical properties than the mirtazapine-casted ODF (C-MTZ), due to the 3D-printing process. The disintegration time of the 3D-MTZ in a simulated salivary fluid, pH 6.8 at 37 °C, was 24.38 s, which is faster than the C-MTZ (46.75 s). The in vitro dissolution study, in 0.1 N HCl at 37 °C, found the 3D-MTZ quickly released the drug by more than 80% in 5 min. This study manifested that 3D-printing technology can potentially be applied for the fabrication of ODF-containing mirtazapine.

3D printed oral solid dosage form: Modified release and improved solubility

Oral solid dosage form is currently the most common used form of drug. 3D Printing, also known as additive manufacturing (AM), can quickly print customized and individualized oral solid dosage form on demand. Compared with the traditional tablet manufacturing process, 3D Printing has many advantages. By rationally selecting the formulation composition and cleverly designing the printing structure, 3D printing can improve the solubility of the drug and achieve precise modify of the drug release. 3D printed oral solid dosage form, however, still has problems such as limitations in formulation selection. And the selection process of the formulation lacks scientificity and standardization. Structural design of some 3D printing approaches is relatively scarce. This article reviews the formulation selection and structure design of 3D printed oral solid dosage form, providing more ideas for achieving modified drug release and solubility improvement of 3D printed oral solid dosage form through more scientific and extensive formulation selection and more sophisticated structural design.

3D Printing of Triamcinolone Acetonide in Triblock Copolymers of Styrene–Isobutylene–Styrene as a Slow-Release System

Additive manufacturing has a wide range of applications and has opened up new methods of drug formulation, in turn achieving attention in medicine. We prepared styrene–isobutylene–styrene triblock copolymers (SIBS; Mn = 10 kDa–25 kDa, PDI 1,3–1,6) as a drug carrier for triamcinolone acetonide (TA), further processed by fused deposition modeling to create a solid drug release system displaying improved bioavailability and applicability. Living carbocationic polymerization was used to exert control over block length and polymeric architecture. Thermorheological properties of the SIBS polymer (22.3 kDa, 38 wt % S) were adjusted to the printability of SIBS/TA mixtures (1–5% of TA), generating an effective release system effective for more than 60 days. Continuous drug release and morphological investigations were conducted to probe the influence of the 3D printing process on the drug release, enabling 3D printing as a formulation method for a slow-release system of Triamcinolone.

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.

Investigation of Patient-Centric 3D-Printed Orodispersible Films Containing Amorphous Aripiprazole

The objective of this study was to design and evaluate an orodispersible film (ODF) composed of aripiprazole (ARP), prepared using a conventional solvent casting technique, and to fuse a three-dimensional (3D) printing technique with a hot-melt extrusion (HME) filament. Klucel® LF (hydroxypropyl cellulose, HPC) and PE-05JPS® (polyvinyl alcohol, PVA) were used as backbone polymers for 3D printing and solvent casting. HPC-, PVA-, and ARP-loaded filaments were applied for 3D printing using HME. The physicochemical and mechanical properties of the 3D printing filaments and films were optimized based on the composition of the polymers and the processing parameters. The crystalline states of drug and drug-loaded formulations were investigated using differential scanning calorimetry (DSC) and powder X-ray diffraction (XRD). The dissolution and disintegration of the 3D-printed films were faster than those of solvent-cast films. HPC-3D printed film was fully disintegrated within 45 ± 3.5 s. The dissolution rate of HPC films reached 80% within 30 min at pH 1.2 and pH 4.0 USP buffer. There was a difference in the dissolution rate of about 5 to 10% compared to PVA films at the same sampling time. The root mean square of the roughness (Rq) values of each sample were evaluated using atomic force microscopy. The higher the Rq value, the rougher the surface, and the larger the surface area, the more salivary fluid penetrated the film, resulting in faster drug release and disintegration. Specifically, The HPC 3D-printed film showed the highest Rq value (102.868 nm) and average surface roughness (85.007 nm). The puncture strength of 3D-printed films had desirable strength with HPC (0.65 ± 0.27 N/mm2) and PVA (0.93 ± 0.15 N/mm2) to prevent deformation compared to those of marketed film products (over 0.34 N/mm2). In conclusion, combining polymer selection and 3D printing technology could innovatively design ODFs composed of ARP to solve the unmet medical needs of psychiatric patients.

The Evolution of the 3D-Printed Drug Delivery Systems: A Review

Since the appearance of the 3D printing in the 1980s it has revolutionized many research fields including the pharmaceutical industry. The main goal is to manufacture complex, personalized products in a low-cost manufacturing process on-demand. In the last few decades, 3D printing has attracted the attention of numerous research groups for the manufacturing of different drug delivery systems. Since the 2015 approval of the first 3D-printed drug product, the number of publications has multiplied. In our review, we focused on summarizing the evolution of the produced drug delivery systems in the last 20 years and especially in the last 5 years. The drug delivery systems are sub-grouped into tablets, capsules, orodispersible films, implants, transdermal delivery systems, microneedles, vaginal drug delivery systems, and micro- and nanoscale dosage forms. Our classification may provide guidance for researchers to more easily examine the publications and to find further research directions.

Effects of Various Drying Times on the Properties of 3D Printed Orodispersible Films

Orodispersible films are an innovative dosage form. Their main advantages are the application comfort and the possibility of personalization. This work aimed to evaluate the influence of different drying times on the properties of orodispersible films of various thicknesses, prepared in two different semisolid extrusion 3D printing setups. In the first experiment, drying times were dependent on the overall print time of each batch. In the second setup, the drying time was set equal according to the longest one. The evaluated parameters were films’ weight uniformity, thickness, moisture content, surface pH, disintegration time, hardness, and tensile strength. Upon statistical comparison, significant differences in the moisture content were found, subsequently affecting the disintegration time. Moreover, statistically significant differences in films’ mechanical properties (hardness, tensile strength) were also described, proving that moisture content simultaneously affects film plasticity and related properties. In conclusion, a mutual comparison of the manufactured orodispersible films showed that the drying time affects their physical and mechanical properties. The in-process drying setup was proved to be sufficient while allowing quicker manufacturing.

The potential of natural products use in fused deposition modeling 3D printing of pharmaceutical dosage forms

In recent years, the interest in 3D printing of medicines has increased due to many advantages of this technology, such as flexibility of the dose and dosage form of the printed product. Fused deposition modeling (FDM) is one of the most popular 3D printing technologies in the pharmaceutical field, due to its low cost and simplicity. The subject of this review is the potential use of natural products as biodegradable and biocompatible materials with good safety profiles in FDM 3D printing of pharmaceuticals. Natural products such as alginate, chitosan and starch have already been employed as excipients in FDM 3D printed pharmaceutical dosage forms, while others like shellac and zein show the potential, but haven't yet been part of 3D printed pharmaceutical formulations. These excipients have different roles in the formulation of filaments for FDM 3D printing, for example as fillers, matrix carriers or drug-release modifiers. In addition, the possibility of incorporating active pharmaceutical ingredients of natural origin in filaments for FDM 3D printing was reviewed. High printing temperatures limit the use of natural products in FDM 3D printing. However, adequate selection of thermoplastic material and printing parameters can widen the use of natural products in FDM 3D printing of pharmaceutical dosage forms.

Machine Learning and Machine Vision Accelerate 3D Printed Orodispersible Film Development

Orodispersible films (ODFs) are an attractive delivery system for a myriad of clinical applications and possess both large economical and clinical rewards. However, the manufacturing of ODFs does not adhere to contemporary paradigms of personalised, on-demand medicine, nor sustainable manufacturing. To address these shortcomings, both three-dimensional (3D) printing and machine learning (ML) were employed to provide on-demand manufacturing and quality control checks of ODFs. Direct ink writing (DIW) was able to fabricate complex ODF shapes, with thicknesses of less than 100 µm. ML algorithms were explored to classify the ODFs according to their active ingredient, by using their near-infrared (NIR) spectrums. A supervised model of linear discriminant analysis was found to provide 100% accuracy in classifying ODFs. A subsequent partial least square algorithm was applied to verify the dose, where a coefficient of determination of 0.96, 0.99 and 0.98 was obtained for ODFs of paracetamol, caffeine, and theophylline, respectively. Therefore, it was concluded that the combination of 3D printing, NIR and ML can result in a rapid production and verification of ODFs. Additionally, a machine vision tool was used to automate the in vitro testing. These collective digital technologies demonstrate the potential to automate the ODF workflow.

Multi-material 3D printing of programmable and stretchable oromucosal patches for delivery of saquinavir

Oromucosal patches for drug delivery allow fast onset of action and ability to circumvent hepatic first pass metabolism of drugs. While conventional fabrication methods such as solvent casting or hot melt extrusion are ideal for scalable production of low-cost delivery patches, these methods chiefly allow for simple, homogenous patch designs. As alternative, a multi-material direct-ink-write 3D printing for rapid fabrication of complex oromucosal patches with unique design features was demonstrated in the present study. Specifically, three print-materials: an acidic saquinavir-loaded hydroxypropyl methylcellulose ink, an alkaline effervescent sodium carbonate-loaded ink, and a methyl cellulose backing material were combined in various designs. The CO₂ content and pH of the microenvironment were controlled by adjusting the number of alkaline layers in the patch. Additionally, the rigid and brittle patches were converted to compliant and stretchable patches by implementing mesh-like designs. Our results illustrate how 3D printing can be used for rapid design and fabrication of multifunctional or customized oromucosal patches with tailored dosages and changed drug permeation.

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.

Quality of FDM 3D Printed Medicines for Pediatrics: Considerations for Formulation Development, Filament Extrusion, Printing Process and Printer Design

3d printing is capable of providing dose individualization for pediatric medicines and translating the precision medicine approach into practical application. In pediatrics, dose individualization and preparation of small dosage forms is a requirement for successful therapy, which is frequently not possible due to the lack of suitable dosage forms. For precision medicine, individual characteristics of patients are considered for the selection of the best possible API in the most suitable dose with the most effective release profile to improve therapeutic outcome. 3d printing is inherently suitable for manufacturing of individualized medicines with varying dosages, sizes, release profiles and drug combinations in small batch sizes, which cannot be manufactured with traditional technologies. However, understanding of critical quality attributes and process parameters still needs to be significantly improved for this new technology. To ensure health and safety of patients, cleaning and process validation needs to be established. Additionally, adequate analytical methods for the in-process control of intermediates, regarding their printability as well as control of the final 3d printed tablets considering any risk of this new technology will be required. The PolyPrint consortium is actively working on developing novel polymers for fused deposition modeling (FDM) 3d printing, filament formulation and manufacturing development as well as optimization of the printing process, and the design of a GMP-capable FDM 3d printer. In this manuscript, the consortium shares its views on quality aspects and measures for 3d printing from drug-loaded filaments, including formulation development, the printing process, and the printed dosage forms. Additionally, engineering approaches for quality assurance during the printing process and for the final dosage form will be presented together with considerations for a GMP-capable printer design.

Modular design principle based on compartmental drug delivery systems

The current manufacturing solutions for oral solid dosage forms are fundamentally based on technologies from the 19th century. This approach is well suited for mass production of one-size-fits-all products; however, it does not allow for a straight-forward personalization and mass customization of the pharmaceutical end-product. In order to provide better therapies to the patients, a need for innovative manufacturing concepts and product design principles has been rising. Additive manufacturing opens up a possibility for compartmentalization of drug products, including design of spatially separated multidrug and functional excipient compartments. This compartmentalized solution can be further expanded to modular design thinking. Modular design is referring to combination of building blocks containing a given amount of drug compound(s) and related functional excipients into a larger final product. Implementation of modular design principles is paving the way for implementing the emerging personalization potential within health sciences by designing compartmental and reactive product structures that can be manufactured based on the individual needs of each patient. This review will introduce the existing compartmentalized product design principles and discuss the integration of these into edible electronics allowing for innovative control of drug release.

Characterization of Hydrophilic Polymers as a Syringe Extrusion 3D Printing Material for Orodispersible Film

The application of hydrophilic polymers in designing and three-dimensional (3D) printing of pharmaceutical products in various dosage forms has recently been paid much attention. Use of hydrophilic polymers and syringe extrusion 3D printing technology in the fabrication of orodispersible films (ODFs) might hold great potential in rapid drug delivery, personalized medicine, and manufacturing time savings. In this study, the feasibility of 3D-printed ODFs fabrication through a syringe extrusion 3D printing technique and using five different hydrophilic polymers (e.g., hydroxypropyl methylcellulose E15, hydroxypropyl methylcellulose E50, high methoxyl pectin, sodium carboxymethylcellulose, and hydroxyethylcellulose) as film-forming polymers and printing materials has been investigated. Rheology properties and printability of printing gels and physicochemical and mechanical properties of 3D-printed ODFs were evaluated. Amongst the investigated hydrophilic polymers, sodium carboxymethylcellulose at a concentration of 5% w/v (SCMC-5) showed promising results with a good printing resolution and accurate dimensions of the 3D-printed ODFs. In addition, SCMC-5 3D-printed ODFs exhibited the fastest disintegration time within 3 s due to high wettability, roughness and porosity on the surface. However, the results of the mechanical properties study showed that SCMC-5 3D printed ODFs were rigid and brittle, thus requiring special packaging to prevent them from any damage before practical use.

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.

Intervention of 3D printing in health care: transformation for sustainable development

INTRODUCTION

Three-dimensional (3D) technology is the practice of dropping material layer-by-layer in the construction of the desired object. The application of the 3D printing technique has been observed in miscellaneous domains. Personalized medicine becomes the most demanding trend in the health-care segment. Several advancements have been observed in the progress of 3D printing. However, the availability of finished products in the marketplace is very less. There is an utmost requirement to improve the knowledge and skills in the sustainable development of pharmaceutical and medical products by selecting suitable techniques and materials.

AREAS COVERED

This article covers the fundamental process of 3D printing, types, pharmaceutical-medical application, benefits, and challenges.

EXPERT OPINION

This technology is capable of designing the complex geometry of an organ. It is feasible to produce drug products by incorporating multiple drugs in various compartments in such a fashion that these drugs can release from the compartment at a predetermined rate. Additionally, this 3D process has the potential to revolutionize personalized therapy to different age-groups through design flexibility and accurate dosing. In the upcoming years, the potential application of this technology can be seen in a clinical setting where patients will get individualized medicine as per their needs.

Mucosal drug delivery and 3D printing technologies: A focus on special patient populations

In the last decade, additive manufacturing (AM) technologies have revolutionized how healthcare provision is envisioned. The rapid evolution of these technologies has already created a momentum in the effort to address unmet personalized needs in large patient groups, especially those belonging to sensitive subgroup populations (e.g., paediatric, geriatric, visually impaired). At the same time, AM technologies have become a salient ally to overcome defined health challenges in drug formulation development by addressing not only the requirement of personalized therapy, but also problems related to lowering non-specific drug distribution and the risk of adverse reactions, enhancing drug absorption and bioavailability, as well as ease of administration and patient compliance. To this end, mucoadhesive drug delivery systems fabricated with the support of AM technologies provide competitive advantages over conventional dosage forms, aiming to entice innovation in drug formulation with special focus on sensitive patient populations.

An Updated Overview of the Emerging Role of Patch and Film-Based Buccal Delivery Systems

Buccal mucosal membrane offers an attractive drug-delivery route to enhance both systemic and local therapy. This review discusses the benefits and drawbacks of buccal drug delivery, anatomical and physiological aspects of oral mucosa, and various in vitro techniques frequently used for examining buccal drug-delivery systems. The role of mucoadhesive polymers, penetration enhancers, and enzyme inhibitors to circumvent the formulation challenges particularly due to salivary renovation cycle, masticatory effect, and limited absorption area are summarized. Biocompatible mucoadhesive films and patches are favored dosage forms for buccal administration because of flexibility, comfort, lightness, acceptability, capacity to withstand mechanical stress, and customized size. Preparation methods, scale-up process and manufacturing of buccal films are briefed. Ongoing and completed clinical trials of buccal film formulations designed for systemic delivery are tabulated. Polymeric or lipid nanocarriers incorporated in buccal film to resolve potential formulation and drug-delivery issues are reviewed. Vaccine-enabled buccal films have the potential ability to produce both antibodies mediated and cell mediated immunity. Advent of novel 3D printing technologies with built-in flexibility would allow multiple drug combinations as well as compartmentalization to separate incompatible drugs. Exploring new functional excipients with potential capacity for permeation enhancement of particularly large-molecular-weight hydrophilic drugs and unstable proteins, oligonucleotides are the need of the hour for rapid advancement in the exciting field of buccal drug delivery.

Challenges of fused deposition modeling 3D printing in pharmaceutical applications: Where are we now?

In recent years, fused deposition modeling has become one of the most used three-dimensional printing technologies in the pharmaceutical field. The production of personalized dosage forms for individualized therapy and the modification of the drug release profile by the elaboration of complex geometries make fused deposition modeling a promising tool for small-scale production. However, fused deposition modeling has a considerable number of challenges to overcome. They are divided into three categories of parameters. Material-specific parameters encompass the physicochemical properties of the filament, like thermal, mechanical and rheological properties. They determine the feasibility of the printing process. Operation-specific parameters relate to the processing conditions of printing, such as printing temperature and infill density, which have an influence on the final quality and on the dissolution behavior of the objects. The printer equipment is defined by the machine-specific parameters. Some modifications of this equipment also enhance the performance of the printing process. The aim of this review is to highlight the major fused deposition modeling critical process parameters in the pharmaceutical field and possible solutions in order to speed up the development of objects in the pharmaceutical market.

The Impact of the Preparation Method on the Properties of Orodispersible Films with Aripiprazole: Electrospinning vs. Casting and 3D Printing Methods

Orodispersible films (ODFs) address the needs of pediatric and geriatric patients and people with swallowing difficulties due to fast disintegration in the mouth. Typically, they are obtained using the solvent casting method, but other techniques such as 3D printing and electrospinning have already been investigated. The decision on the manufacturing method is of crucial importance because it affects film properties. This study aimed to compare electrospun ODFs containing aripiprazole and polyvinyl alcohol with films prepared using casting and 3D printing methods. Characterization of films included DSC and XRD analysis, microscopic analysis, the assessment of mechanical parameters, disintegration, and dissolution tests. Simplified stability studies were performed after one month of storage. All prepared films met acceptance criteria for mechanical properties. Electrospun ODFs disintegrated in 1.0 s, which was much less than in the case of other films. Stability studies have shown the sensitivity of electrospun films to the storage condition resulting in partial recrystallization of ARP. These changes negatively affected the dissolution rate, but mechanical properties and disintegration time remained at a desirable level. The results demonstrated that electrospun fibers are promising solutions that can be used in the future for the treatment of patients with swallowing problems.

3D printing technology in healthcare: applications, regulatory understanding, IP repository and clinical trial status

Mass consumerization of three-dimensional (3D) printing innovation has revolutionised admittance of 3D-printing in an expansive scope of ventures. When utilised predominantly for industrial manufacturing, 3D-printing strategies have rapidly attained acquaintance in different parts of health care industry. 3D-printing is a moderately new technology that has discovered promising applications in the medication conveyance and clinical areas. This review intends to explore different parts of 3D- printing innovation concerning pharmaceutical and clinical applications. Review on pharmaceutical products like tablets, caplets, films, polypills, microdots, biodegradable patches, medical devices (uterine and subcutaneous), patient specific implants, cardiovascular stents, etc. and prosthetics/anatomical structures, surgical models, organs and tissues created utilising 3D-printing is being presented. In addition, the regulatory understanding and current IP and clinical trial status pertaining to 3D fabricated products/medical applications have also been funnelled, garnering information from different web portals of regulatory agencies and databases. It is additionally certain that for such new innovations, there would be difficulties and questions before these are acknowledged as protected and viable. The circumstance demands purposeful and wary endeavours to acquire regulations which would at last prompt the accomplishment of this progressive innovation, thus various regulatory challenges faced have been conscientiously discussed.

3D printing in personalized drug delivery: An overview of hot-melt extrusion-based fused deposition modeling

Advancements in pharmaceutical technologies have led to the personalization of therapies over the last decade. Three-dimensional printing (3DP) is an emerging technique in the manufacturing of pharmaceutical dosage forms because of its potential to create complex and customized dosage forms according to the patient's needs. Among the various 3DP techniques based on different functioning mechanisms, fused deposition modeling (FDM) 3D printing is a versatile and widely used method with advantages such as precision of quantity and the ability to incorporate different fill densities. This method is also economical and easily produces complex designs. Hot-melt extrusion (HME) is an established technique in pharmaceutical manufacturing that is utilized in the development of filaments which are used as "ink roll" or feedstock material in FDM 3D printing. This review discusses the various stages involved in FDM 3D printing, including feedstock filament preparation using HME, digital dosage form designs, filament characterization, and various novel applications, and future perspectives.

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.

Printing Methods in the Production of Orodispersible Films

Orodispersible film (ODF) formulations are promising and progressive drug delivery systems that are widely accepted by subjects across all the age groups. They are traditionally fabricated using the most popular yet conventional method called solvent casting method. The most modern and evolving method is based on printing technologies and such printed products are generally termed as printed orodispersible films (POFs). This modern technology is well suited to fabricate ODFs across different settings (laboratory or industrial) in general and in a pharmacy setting in particular. The present review provides an overview of various printing methods employed in fabricating POFs. Particularly, it provides insight about preparing POFs using inkjet, flexographic, and three-dimensional printing (3DP) or additive manufacturing techniques like filament deposition modeling, hot-melt ram extrusion 3DP, and semisolid extrusion 3DP methods. Additionally, the review is focused on patenting trends in POFs using ESPACENET, a European Patent Office search database. Finally, the review captures future market potential of 3DP in general and ODFs market potential in particular.

Automated digital design for 3D-printed individualized therapies

Customization of pharmaceutical products is a central requirement for personalized medicines. However, the existing processing and supply chain solutions do not support such manufacturing-on-demand approaches. In order to solve this challenge, three-dimensional (3D) printing has been applied for customization of not only the dose and release characteristics, but also appearance of the product (e.g., size and shape). A solution for customization can be realized via non-expert-guided processing of digital designs and drug dose. This study presents a proof-of-concept computational algorithm which calculates the optimal dimensions of grid-like orodispersible films (ODFs), considering the recommended dose. Further, the algorithm exports a digital design file which contains the required ODF configuration. Cannabidiol (CBD) was incorporated in the ODFs, considering the simple correspondence between the recommended dose and the patient's weight. The ODFs were 3D-printed and characterized for their physicochemical, mechanical, disintegration and drug release properties. The algorithm was evaluated for its accuracy on dose estimation, highlighting the reproducibility of individualized ODFs. The in vitro performance was principally affected by the thickness and volume of the grid-like structures. The concept provides an alternative approach that promotes automation in the manufacturing of personalized medications in distributed points of care, such as hospitals and local pharmacies.

Tailoring immediate release FDM 3D printed tablets using a quality by design (QbD) approach

The aims of this work were to produce immediate release printed tablets using fused deposition modelling (FDM) technique and to systematically explore the effects of different compositions on drug release by Quality by Design approach. Screening studies of various drug loadings and excipients were conducted by hot melt extrusion and FDM printing to set up the appropriate limit of each independent factor (critical material attribute, CMA) in Design of Experiment. This study demonstrated that the use of polymeric mixture containing different theophylline loadings (10, 30 and 60% w/w) in combination with multiple pharmaceutical polymers (hydroxy propyl cellulose (HPC), Eudragit® EPO, Kollidon® VA 64) and disintegrant (sodium starch glycolate) were successfully hot melt-extruded and FDM printed with no plasticizer. Rheological measurement was performed to understand the critical process parameters (CPP) while the mechanical property of extrudable and printable filaments was investigated by 3-point test for the formulation development. Surprisingly, HPC were found to be superior as a flexibility modifier in all printable filaments. A range of pharmaceutical characterizations were examined to ensure the critical quality attributes (CQA). Characteristic dissolution profiles were obtained. D-optimal mixture design of 17 formulations suggested that theophylline release was considerably affected by the combined action of different excipients and could predict the optimum formulation with the required quality target product profile (QTPP) in pharmacopoeia (85% release at 30 min). Therefore, this can be a useful platform to develop immediate release products for a specific group of patients commercially.

Fundamental Investigations into Metoprolol Tartrate Deposition on Orodispersible Films by Inkjet Printing for Individualised Drug Dosing

Individualised medicine is continuously gaining attention in pharmaceutical research. New concepts and manufacturing technologies are required to realise this therapeutic approach. Off-label drugs used in paediatrics, such as metoprolol tartrate (MPT), are potential candidates for innovations in this context. Orodispersible films (ODFs) have been shown as an accepted alternative dosage form during the last years and inkjet printing is traded as seminal technology of precise deposition of active pharmaceutical ingredients (APIs). The objective of this study was to combine both technologies by developing imprinted ODFs based on hypromellose with therapeutically reasonable MPT single doses of 0.35 to 3.5 mg for paediatric use. After preselection, suitable ink compositions were analysed by confocal Raman microscopy regarding MPT distribution within the imprinted ODFs. Adjusted print settings, speed, print direction and angle, characterised the final ODF surface structure. The present investigations show that uniform dosages with acceptance values between 1 and 6 can be achieved. Nevertheless, changes in calibrated printed quantity due to nozzle aging have a significant effect on the final applied dose. At the lowest investigated quantity, the RSD was ±28% and at the highest, ±9%. This has to be considered for implementation of inkjet printing as a pharmaceutical production tool in the future.

Extrusion-based 3D printing of oral solid dosage forms: Material requirements and equipment dependencies

Extrusion-based 3D printing is steadily gaining importance as a manufacturing technique due to its flexibility and wide range of possible end-products. In the medical field, the technique is being exploited for a variety of applications and one of these is the production of personalised medicines. However, despite many proof-of-concept studies, more thorough insights in the production technique itself and the required material properties are needed before 3D printing can be fully exploited in a hospital or pharmacy setting. This research aims at clarifying the complex interplay between material properties, process parameters and printer-dependent variables. A variety of different polymers and polymer-drug blends were extruded (diameter 1.75±0.05 mm) and characterised in terms of mechanical, thermal and rheological properties. These properties, together with the processing temperature, printing speeds and different nozzle diameters of the 3D printer were linked to the quality of the end-product. Different failure mechanisms (mechanical, thermal) were assessed. Decisive material parameters (e.g. cross-over point) for optimal printing behaviour and the importance of printer construction (nozzle diameter) were clarified. In general, this study offers insight into the 3D printing process and will help to speed up future pharmaceutical formulation development for printlets.