Three-Dimensional Printing of Carbamazepine Sustained-Release Scaffold

Medical, pharmaceutical, and nutritional applications of 3D-printing technology in diabetes

AIMS

Despite numerous studies covering the various features of three-dimensional printing (3D printing) technology, and its applications in food science and disease treatment, no study has yet been conducted to investigate applying 3D printing in diabetes. Therefore, the present study centers on the utilization and impact of 3D printing technology in relation to the nutritional, pharmaceutical, and medicinal facets of diabetes management. It highlights the latest advancements, and challenges in this field.

METHODS

In this review, the articles focusing on the application and effect of 3D printing technology on medical, pharmaceutical, and nutritional aspects of diabetes management were collected from different databases.

RESULT

High precision of 3D printing in the placement of cells led to accurate anatomic control, and the possibility of bio-printing pancreas and β-cells. Transdermal drug delivery via 3D-printed microneedle (MN) patches was beneficial for the management of diabetes disease. 3D printing supported personalized medicine for Diabetes Mellitus (DM). For instance, it made it possible for pharmaceutical companies to manufacture unique doses of medications for every diabetic patient. Moreover, 3D printing allowed the food industry to produce high-fiber and sugar-free products for the individuals with DM.

CONCLUSIONS

In summary, applying 3D printing technology for diabetes management is in its early stages, and needs to be matured and developed to be safely used for humans. However, its rapid progress in recent years showed a bright future for the treatment of diabetes.

Mass Customization of Polylactic Acid (PLA) Parts via a Hybrid Manufacturing Process

Mass customization is the development of items tailored to specific customers, but produced at low unit cost in high-volume. In this context, hybrid manufacturing (HM) combines fused deposition modeling (FDM) and injection molding (IM) to fabricate a single personalized part with minimum manufacturing cost. In this technique, inserts with different physical features are first FDM-fabricated and then IM-overmolded. This study investigated the effect of hybrid FDM-IM production technology, FDM insert geometry on mechanical properties, and micro-structural evolution of Polylactic Acid (PLA) samples. The findings indicated a comparable tensile properties of FDM-IM samples (68.38 MPa) to IM batch (68.95 MPa), emphasizing the potential of HM in the manufacturing industry. Maximum tensile stress of FDM-IM specimens shows an upward trend due to the increased infill density of preforms. In addition, overmolding interface direction results in a big gap for the maximum tensile strengths between half-length series specimens (12.99 MPa to 19.09 MPa) and half-thickness series specimens (53.83 MPa to 59.92 MPa). Furthermore, four joint configurations resulted in different mechanical performances of finished specimens, in which the female cube sample exhibits the highest tensile stress (68.38 MPa), while the batch with male T joint shows a lower value in maximum tensile strength (59.51 MPa), exhibiting a similar tensile performance with the half-thickness 75% batch without joint configuration. This study lays the groundwork for using HM to produce bespoke and mechanically improved parts over FDM alone.

Transdermal delivery via medical device technologies

INTRODUCTION

Despite their effectiveness and indispensability, many drugs are poorly solvated in aqueous solutions. Over recent decades, the need for targeted drug delivery has led to the development of pharmaceutical formulations with enhanced lipid solubility to improve their delivery properties. Therefore, a dependable approach for administering lipid-soluble drugs needs to be developed.

AREAS COVERED

The advent of 3D printing or additive manufacturing (AM) has revolutionized the development of medical devices, which can effectively enable the delivery of lipophilic drugs to the targeted tissues. This review focuses on the use of microneedles and iontophoresis for transdermal drug delivery. Microneedle arrays, inkjet printing, and fused deposition modeling have emerged as valuable approaches for delivering several classes of drugs. In addition, iontophoresis has been successfully employed for the effective delivery of macromolecular drugs.

EXPERT OPINION

Microneedle arrays, inkjet printing, and fused deposition are potentially useful for many drug delivery applications; however, the clinical and commercial adoption rates of these technologies are relatively low. Additional efforts is needed to enable the pharmaceutical community to fully realize the benefits of these technologies.

3D printing of bioactive materials for drug delivery applications

INTRODUCTION

Three-dimensional (3D) printing, also known as additive manufacturing (AM), is a modern technique/technology, which makes it possible to construct 3D objects from computer-aided design (CAD) digital models. This technology can be used in the progress of drug delivery systems, where porosity has played important role in attaining an acceptable level of biocompatibility and biodegradability with improved therapeutic effects. 3D printing may also provide the user possibility to control the dosage of each ingredient in order to a specific purpose, and makes it probable to improve the formulation of drug delivery systems.

AREAS COVERED

This article covers the 3D printing technologies, bioactive materials including natural and synthetic polymers as well as some ceramics and minerals and their roles in drug delivery systems.

EXPERT OPINION

This technology is feasible to fabricate drug products by incorporating multiple drugs in different parts in such a mode that these drugs can release from the section at a predetermined rate. Furthermore, this 3D printing technology has the possible to transform personalized therapy to various age-groups by design flexibility and precise dosing. In recent years, the potential use of this technology can be realized in a clinical situation where patients will acquire individualized medicine as per their require.

Traction of 3D and 4D Printing in the Healthcare Industry: From Drug Delivery and Analysis to Regenerative Medicine

Three-dimensional (3D) printing and 3D bioprinting are promising technologies for a broad range of healthcare applications from frontier regenerative medicine and tissue engineering therapies to pharmaceutical advancements yet must overcome the challenges of biocompatibility and resolution. Through comparison of traditional biofabrication methods with 3D (bio)printing, this review highlights the promise of 3D printing for the production of on-demand, personalized, and complex products that enhance the accessibility, effectiveness, and safety of drug therapies and delivery systems. In addition, this review describes the capacity of 3D bioprinting to fabricate patient-specific tissues and living cell systems (e.g., vascular networks, organs, muscles, and skeletal systems) as well as its applications in the delivery of cells and genes, microfluidics, and organ-on-chip constructs. This review summarizes how tailoring selected parameters (i.e., accurately selecting the appropriate printing method, materials, and printing parameters based on the desired application and behavior) can better facilitate the development of optimized 3D-printed products and how dynamic 4D-printed strategies (printing materials designed to change with time or stimulus) may be deployed to overcome many of the inherent limitations of conventional 3D-printed technologies. Comprehensive insights into a critical perspective of the future of 4D bioprinting, crucial requirements for 4D printing including the programmability of a material, multimaterial printing methods, and precise designs for meticulous transformations or even clinical applications are also given.

3D printing of bioinspired compartmentalized capsular structure for controlled drug release

Drug delivery with customized combinations of drugs, controllable drug dosage, and on-demand release kinetics is critical for personalized medicine. In this study, inspired by successive opening of layered structures and compartmentalized structures in plants, we designed a multiple compartmentalized capsular structure for controlled drug delivery. The structure was designed as a series of compartments, defined by the gradient thickness of their external walls and internal divisions. Based on the careful choice and optimization of bioinks composed of gelatin, starch, and alginate, the capsular structures were successfully manufactured by fused deposition modeling three-dimensional (3D) printing. The capsules showed fusion and firm contact between printed layers, forming complete structures without significant defects on the external walls and internal joints. Internal cavities with different volumes were achieved for different drug loading as designed. In vitro swelling demonstrated a successive dissolving and opening of external walls of different capsule compartments, allowing successive drug pulses from the capsules, resulting in the sustained release for about 410 min. The drug release was significantly prolonged compared to a single burst release from a traditional capsular design. The bioinspired design and manufacture of multiple compartmentalized capsules enable customized drug release in a controllable fashion with combinations of different drugs, drug doses, and release kinetics, and have potential for use in personalized medicine.

Metamorphosis of Twin Screw Extruder-Based Granulation Technology: Applications Focusing on Its Impact on Conventional Granulation Technology

In order to be at pace with the market requirements of solid dosage forms and regulatory standards, a transformation towards systematic processing using continuous manufacturing (CM) and automated model-based control is being thought through for its fundamental advantages over conventional batch manufacturing. CM eliminates the key gaps through the integration of various processes while preserving quality attributes via the use of process analytical technology (PAT). The twin screw extruder (TSE) is one such equipment adopted by the pharmaceutical industry as a substitute for the traditional batch granulation process. Various types of granulation techniques using twin screw extrusion technology have been explored in the article. Furthermore, individual components of a TSE and their conjugation with PAT tools and the advancements and applications in the field of nutraceuticals and nanotechnology have also been discussed. Thus, the future of granulation lies on the shoulders of continuous TSE, where it can be coupled with computational mathematical studies to mitigate its complications.

Stereolithography 3D printing technology in pharmaceuticals: a review

Three-dimensional printing (3DP) technology is an innovative tool used in manufacturing medical devices, producing alloys, replacing biological tissues, producing customized dosage forms and so on. Stereolithography (SLA), a 3D printing technique, is very rapid and highly accurate and produces finished products of uniform quality. 3D formulations have been optimized with a perfect tool of artificial intelligence learning techniques. Complex designs/shapes can be fabricated through SLA using the photopolymerization principle. Different 3DP technologies are introduced and the most promising of these, SLA, and its commercial applications, are focused on. The high speed and effectiveness of SLA are highlighted. The working principle of SLA, the materials used and applications of the technique in a wide range of different sectors are highlighted in this review. An innovative idea of 3D printing customized pharmaceutical dosage forms is also presented. SLA compromises several advantages over other methods, such as cost effectiveness, controlled integrity of materials and greater speed. The development of SLA has allowed the development of printed pharmaceutical devices. Considering the present trends, it is expected that SLA will be used along with conventional methods of manufacturing of 3D model. This 3D printing technology may be utilized as a novel tool for delivering drugs on demand. This review will be useful for researchers working on 3D printing technologies.

3D Printing of Pharmaceutical Application: Drug Screening and Drug Delivery

Advances in three-dimensional (3D) printing techniques and the development of tailored biomaterials have facilitated the precise fabrication of biological components and complex 3D geometrics over the past few decades. Moreover, the notable growth of 3D printing has facilitated pharmaceutical applications, enabling the development of customized drug screening and drug delivery systems for individual patients, breaking away from conventional approaches that primarily rely on transgenic animal experiments and mass production. This review provides an extensive overview of 3D printing research applied to drug screening and drug delivery systems that represent pharmaceutical applications. We classify several elements required by each application for advanced pharmaceutical techniques and briefly describe state-of-the-art 3D printing technology consisting of cells, bioinks, and printing strategies that satisfy requirements. Furthermore, we discuss the limitations of traditional approaches by providing concrete examples of drug screening (organoid, organ-on-a-chip, and tissue/organ equivalent) and drug delivery systems (oral/vaginal/rectal and transdermal/surgical drug delivery), followed by the introduction of recent pharmaceutical investigations using 3D printing-based strategies to overcome these challenges.

Recent Advances in 3D Printing for Parenteral Applications

3D printing has emerged as an advanced manufacturing technology in the field of pharmaceutical sciences. Despite much focus on enteral applications, there has been a lack of research focused on potential benefits of 3D printing for parenteral applications such as wound dressings, biomedical devices, and regenerative medicines. 3D printing technologies, including fused deposition modeling, vat polymerization, and powder bed printing, allow for rapid prototyping of personalized medications, capable of producing dosage forms with flexible dimensions based on patient anatomy as well as dosage form properties such as porosity. Considerations such as printing properties and material selection play a key role in determining overall printability of the constructs. These parameters also impact drug release kinetics, and mechanical properties of final printed constructs, which play a role in modulating immune response upon insertion in the body. Despite challenges in sterilization of printed constructs, additional post-printing processing procedures, and lack of regulatory guidance, 3D printing will continue to evolve to meet the needs of developing effective, personalized medicines for parenteral applications.

3D printing of four-in-one oral polypill with multiple release profiles for personalized delivery of caffeine and vitamin B analogues

Personalized supplementation has found recent momentum with an estimated global market size of USD 1.6 billion in 2019 and an expected CAGR of 8.5% between 2020 and 2028. Alongside this rising trend, a simple, accurate, inexpensive and flexible method to produce personalized dosage forms of a wide variety of supplements would be beneficial to both the industry players and individual consumers. Here, we present a 3D printing method to fabricate a four-in-one oral polypill with multiple release profiles for personalized delivery of caffeine and vitamin B analogues. The 3D printable formulations were fabricated and optimized from existing FDA GRAS excipients based on their viscosity, shear thinning properties, recovery of paste and mechanical strength. In the polypill, vitamin B analogues and caffeine were used as the model dietary ingredients. We performed a standard 2 stage USP in vitro dissolution test of the polypill, and demonstrated that vitamin B1, B3 and B6 could be immediately released within 30 min, while caffeine could be slowly released over a period of 4 h. This demonstrated the ability dietary supplement containing different ingredients with varying release profiles, all within a single polypill. Throughout the formulation and 3D printing process, there were no detectable changes to the dietary ingredients nor any interactions with the excipients. This method serves as an intriguing complement to traditional manufacturing of oral tablets, especially when flexibility in design, dose, volume and release profiles of each dietary ingredient is required, as exemplified in personalized supplementation.

3D-printed tablets using a single-step hot-melt pneumatic process for poorly soluble drugs

Main purpose was to evaluate the applicability of a 3D-printer equipped with a hot-melt pneumatic dispenser as a single-step process to prepare tablet dosage forms. Dutasteride, a poorly water-soluble drug, was selected as a model drug. Soluplus®, Kollidon® VA 64, Eudragit® E PO, and hydroxypropyl cellulose (HPC) were premixed as bulking agents prior to printing. Differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA) were utilized to evaluate the physicochemical properties of the 3D-printed tablets. Moreover, different geometries were designed to correlate the surface area/volume (SA/V) of the tablets with respect to their release profiles. As a result, printed dutasteride was confirmed to be in an amorphous state and not recrystallized even after the accelerated storage stability. Out of the four bulking agents, Kollidon® VA 64, enhanced the dissolution of the printed dutasteride, reaching above 80% within 15 min. These results suggest that the hot-melt pneumatic dispenser was efficient in converting the solid state into an amorphous state, which significantly enhanced the dissolution. On the other hand, the tube-shaped 3D-printed tablet exhibited the fastest drug dissolution profile, which had the highest SA/V ratio in comparison to the cube, hemisphere, and pyramid shapes. These results confirm the dependency of the drug dissolution rate not only on its crystallinity but also on the surface area of the 3D-printed tablet. Therefore, a 3D-printer equipped with a hot-melt pneumatic dispenser possesses useful applicability in enhancing drug dissolution, especially for poorly water-soluble drugs, in a single-step process.

Application of Extrusion-Based 3D Printed Dosage Forms in the Treatment of Chronic Diseases

Chronic disease management has been a significant burden in many countries. As most treatment options involve long-term pharmacotherapy, patient compliance has been a challenge, as patients have to remember taking medications on time at the prescribed dose for each disease state. Patients are often required to split the dosage unit, which may lead to under- or over-dose and dose-related adverse effects. However, 3D printing technologies have been used for fabricating personalized medications and multiple drugs in a single dose unit (polypills), which might greatly reduce treatment monitoring, dosing errors, and follow-ups with the health care providers. Extrusion-based 3D printing is the most used technology to fabricate polypills and to customize the dose, dosage form, and release kinetics, which might potentially reduce the risk of patient non-compliance. Although extrusion-based 3D printing has existed for some time, interest in its potential to fabricate dosage forms for treating chronic diseases is still in its infancy. This review focuses on the various extrusion-based 3D printing technologies such as fused deposition modeling, pressure-assisted microsyringe, and direct powder extrusion 3D printing in the preparation of customizable, multi-drug dosage forms for treating chronic diseases.

Basit A. 3D Printing of Tunable Zero-Order Release Printlets

Zero-order release formulations are designed to release a drug at a constant rate over a prolonged time, thus reducing systemic side effects and improving patience adherence to the therapy. Such formulations are traditionally complex to manufacture, requiring multiple steps. In this work, fused deposition modeling (FDM) 3D printing was explored to prepare on-demand printlets (3D printed tablets). The design includes a prolonged release core surrounded by an insoluble shell able to provide zero-order release profiles. The effect of drug loading (10, 25, and 40% w/w paracetamol) on the mechanical and physical properties of the hot melt extruded filaments and 3D printed formulations was evaluated. Two different shell 3D designs (6 mm and 8 mm diameter apertures) together with three different core infills (100, 50, and 25%) were prepared. The formulations showed a range of zero-order release profiles spanning 16 to 48 h. The work has shown that with simple formulation design modifications, it is possible to print extended release formulations with tunable, zero-order release kinetics. Moreover, by using different infill percentages, the dose contained in the printlet can be infinitely adjusted, providing an additive manufacturing route for personalizing medicines to a patient.

Development of a 3D-printed Medication Label for the Blind and Visually Impaired

This study explored the potential of three-dimensional printing (3DP) technology in producing a three-dimensional (3D) medication label for blind and visually impaired (BVI) patients to ease their drug administration. Different variations of label wordings, dosing instructions, and medication identifiers were designed with reference to guidelines by the American Foundation for the Blind. Shapes and symbols were used as dosing instructions and medication identifiers to the patient's medical conditions. Prototype designs were created with common graphics computer-assisted drafting software and 3D-printed using acrylonitrile butadiene styrene as the polymer filament. Feedback was then obtained from five people with normal vision and four BVI persons. The initial prototype comprised four components, namely, medication name and strength, patient's name, dosing instruction, and medication identifier. A revised label comprising the latter two components was developed after feedback by BVI persons. Words were in all uppercase and regular font type, with a 5-mm center-to-center letter spacing. Elevation heights of the letters alternated between 1 mm and 1.5 mm. A half sphere represented the medication dose unit, while vertical lines and a horizontal center line with alternating elevation of arrowheads represented the frequency of administration and the medication's consumption in relation to food, respectively. Symbols based on target organs were used as medication identifiers. With rapid advancements in 3DP technologies, there is tremendous potential for producing 3D labels in patients' medication management.

Micro and nanoscale technologies in oral drug delivery

Oral administration is a pillar of the pharmaceutical industry and yet it remains challenging to administer hydrophilic therapeutics by the oral route. Smart and controlled oral drug delivery could bypass the physiological barriers that limit the oral delivery of these therapeutics. Micro- and nanoscale technologies, with an unprecedented ability to create, control, and measure micro- or nanoenvironments, have found tremendous applications in biology and medicine. In particular, significant advances have been made in using these technologies for oral drug delivery. In this review, we briefly describe biological barriers to oral drug delivery and micro and nanoscale fabrication technologies. Micro and nanoscale drug carriers fabricated using these technologies, including bioadhesives, microparticles, micropatches, and nanoparticles, are described. Other applications of micro and nanoscale technologies are discussed, including fabrication of devices and tissue engineering models to precisely control or assess oral drug delivery in vivo and in vitro, respectively. Strategies to advance translation of micro and nanotechnologies into clinical trials for oral drug delivery are mentioned. Finally, challenges and future prospects on further integration of micro and nanoscale technologies with oral drug delivery systems are highlighted.

3D Printing Technology in Customized Drug Delivery System: Current State of the Art, Prospective and the Challenges

BACKGROUND

3D printing/Additive Manufacturing seems a pragmatic approach to realize the quest for a truly customized and personalized drug delivery. 3DP technology, with innovations in pharmaceutical development and an interdisciplinary approach to finding newer Drug Delivery Systems can usher a new era of treatments to various diseases. The true potential of this is yet to be realized, and the US-FDA is focusing on the regulatory science of 3D printed medical devices to help patients access this technology safely and effectively. The approval of the first 3D printed prescription medicine by FDA is a promising step in the translation of more research in this area.

METHODS

A web-search on PubMed, ScienceDirect, and Nature was performed with the keywords Customized 3D printing and Drug delivery, publications dealing with the aspects of drug delivery using 3D printing for personalized or customized delivery were further considered and analyzed and discussed.

RESULTS

We present the advantages offered by 3DP over conventional methods of formulation development and discuss the current state of 3DP in pharmaceutics and how it can be used to develop a truly customized drug delivery system, various 3DP technologies including Stereolithography (SLA), Selective Laser Sintering (SLS), Fused Deposition Modelling (FDM), Pressure Assisted Microsyringe (PAM) that have been used to develop pharmaceutical products have been discussed along with their limitations and also the regulatory considerations to help formulation scientists envisaging research in this area with the necessary information.

CONCLUSION

3D printing has the potential to fabricate a customized drug delivery system. Presence of many drug formulation and the devices are already in the regulatory approval process indicating its success.

Mass-customization of oral tablets via the combination of 3D printing and injection molding

The new frontier of medicine is the personalization of treatment to match a patient's individual needs. Fused-filament fabrication (FFF) offers a platform for the personalization of drug dosage forms, but one of its chief shortcomings compared to other tablet production methods such as dry compression and wet granulation is relatively low throughput. Conversely, injection molding (IM) is a manufacturing technique for the high-volume production of parts, but in which individual part customization is both expensive and slow requiring the modification of expensive mold tooling. Mass-customization is the manufacture of custom products that match the needs of individual consumers but which are produced at the low unit cost associated with high-volume production. We successfully integrated for the first time FFF with IM in a multi-step manufacturing process for the production of custom bilayer tablets loaded with two active pharmaceutical ingredients used in the treatment of cardiovascular disease. The FFF layer was loaded with the diuretic hydrochlorothiazide, while the IM layer was loaded with lovastatin. Infill percentage was varied for the FFF layer as a means to modify drug release. The IM injection pressure was evaluated for its effect on drug release and layer-layer adhesion. The bilayer tablets obtained offered different combinations of drug release profiles, which were governed by a combination of factors, including surface area to volume ratio; IM injection volume penetration into the FFF layer; FFF infill percentage; layer tortuosity and porosity. These different parameters could be utilized to modify the individual release of both drugs from the bilayer tablet. Thus for the first time, we have demonstrated a viable method for the mass-customization of oral tablets which could hasten the rollout of personalized medicine.

A miniaturized device for biomembrane permeation analysis

Transdermal drug delivery is widely investigated as an alternative drug administration route to oral delivery and hypodermic injections. Owing to the availability of human skin samples, in vitro tests are used to predict the in vivo delivery of transdermal drugs. The most widely used validation method is skin permeation using diffusion cells. Traditional diffusion cells, however, are capacious and often require large amounts of skin sample and drugs, which is undesirable, given the scarcity of new drug entities and the limitation of skin sample supply. In this study, we fabricated miniaturized multichannel devices (MCDs) by 3D printing, to minimize the use of skin and drug samples. The MCDs were compared with conventional static diffusion cells and achieved comparable drug permeation profiles. The finite element method-based simulation revealed the efficient carry-off of permeated ingredients by the multichannel devices, and a critical role of distance between the buffer stream and skin sample in determining the flow velocity inside the chamber. The results support these devices as qualified alternatives to Franz cells for in vitro permeation studies using biomembranes, with reduced use of skin and drug samples.

An Effective Technology for the Development of Immediate Release Solid Dosage Forms Containing Low-Dose Drug: Fused Deposition Modeling 3D Printing

PURPOSE

Fabrication of immediate release (IR) tablet formulations with rapid release profile via fused deposition modeling 3D printing (FDM 3DP) is a challenge. The aims of this study were to prepare IR tablets with different dissolution profiles and to increase their in vitro dissolution rates by making physical modifications on them. Pramipexole was used as the model low-dose drug.

METHODS

Polymeric filaments were prepared with six different combinations of Eudragit EPO and poly(ethylene) oxide by hot melt extrusion and 3D tablets were produced using an FDM printer. Characterization studies for the filaments and tablets were carried out. The printability of the filaments was also evaluated using a novel mechanical characterization method. Tablet formulation with optimum dissolution profile was chosen and physical modifications (infill %, shape change and thickness) on this formulation were made.

RESULTS

Low-dose pramipexole loading filaments and 3D tablets were homogenously prepared. The printability of the filaments was related to their flexibility. With the physical modifications, the drug release completion time of the tablets reduced to 5 min.

CONCLUSIONS

The same rapid release profiles with conventional IR tablets can be reached by making only physical changes on 3D tablets without using any filling or disintegrating agents.

Flexibility of 3D Extruded Printing for a Novel Controlled-Release Puerarin Gastric Floating Tablet: Design of Internal Structure

The objective of this study was to investigate the development of a novel puerarin gastric floating system with a concentric annular internal pattern by a 3D extrusion-based printing technique and to explore the flexibility of turning the release behavior through the design of the internal structure. The composition consisted of the conventional sustained-release pharmaceutical excipients without addition of foaming agent or light materials. First, the proper alcohol/water proportion was selected for the binding agent. The desired drug release behaviors and good floating properties were obtained either through modification of the formulation composition or adjustment of the internal structure. In vitro, the printed tablets were evaluated for drug release, mechanical properties, lag time, and floating duration time. The in vivo behaviors of the formulations were noted at certain time intervals through assessment of the radiographic pictures of healthy volunteers. The gastric retention time in the 3D-printed tablet was approximately 6 h in vivo. Results indicated these puerarin gastric floating 3D-printed tablets had great potential to achieve good gastric residence time and controlled release. Therefore, 3D extrusion-based printing appears to be appropriate for the production of oral administration systems, owing to its flexibility and the great floating ability and controlled-release capacity of its products.

Development of a gastroretentive delivery system for acyclovir by 3D printing technology and its in vivo pharmacokinetic evaluation in Beagle dogs

Gastroretentive (GR) systems are designed to prolong gastric residence time to allow sustained absorption and improve the oral bioavailability of drugs with a narrow absorption window in the upper part of the gastrointestinal tract. The present study aimed to develop a GR system for acyclovir using 3D printing technology and evaluate its in vivo pharmacokinetics after oral administration in Beagle dogs. The system consisted of a gastro-floating device, which can float in the gastric fluid, prepared by a fused deposition modeling 3D printer and conventional acyclovir sustained-release (SR) tablet. The acyclovir SR tablet was inserted to the floating device to allow sustained release of the drug in the stomach. The buoyancy and sustained-release property of the developed GR system were determined using an in vitro dissolution test, in vivo pharmacokinetic study, and abdominal X-ray imaging in Beagle dogs. The in vivo dissolution profiles of the GR system were also predicted based on the in vivo pharmacokinetic data using a population pharmacokinetic (POP-PK) model. In the dissolution test, the sustained-release characteristic of the GR system was identified with a time corresponding to 80% dissolution (T₈₀) of 2.52 h. Following oral administration of the GR system, the time to reach the maximum concentration (T_max) of acyclovir was significantly prolonged, whereas the maximum concentration (C_max) decreased and the area under the curve increased compared with those obtained after the administration of immediate-release and SR tablets, indicating prolonged absorption. By X-ray imaging, we showed that the developed GR system stayed in the stomach for more than 12 h. The POP-PK model successfully described the observed plasma concentration-time data and predicted the in vivo biphasic dissolution profiles of the GR system, which was significantly different from the in vitro dissolution. The developed GR system could be applied to various drugs and had great prospects in the design and development of novel controlled-release formulations.

Engineering a multifunctional 3D-printed PLA-collagen-minocycline-nanoHydroxyapatite scaffold with combined antimicrobial and osteogenic effects for bone regeneration

3D-printing and additive manufacturing can be powerful techniques to design customized structures and produce synthetic bone grafts with multifunctional effects suitable for bone repair. In our work we aimed the development of novel multifunctionalized 3D printed poly(lactic acid) (PLA) scaffolds with bioinspired surface coatings able to reduce bacterial biofilm formation while favoring human bone marrow-derived mesenchymal stem cells (hMSCs) activity. For that purpose, 3D printing was used to prepare PLA scaffolds that were further multifunctionalized with collagen (Col), minocycline (MH) and bioinspired citrate- hydroxyapatite nanoparticles (cHA). PLA-Col-MH-cHA scaffolds provide a closer structural support approximation to native bone architecture with uniform macroporous, adequate wettability and an excellent compressive strength. The addition of MH resulted in an adequate antibiotic release profile that by being compatible with local drug delivery therapy was translated into antibacterial activities against Staphylococcus aureus, a main pathogen associated to bone-related infections. Subsequently, the hMSCs response to these scaffolds revealed that the incorporation of cHA significantly stimulated the adhesion, proliferation and osteogenesis-related gene expression (RUNX2, OCN and OPN) of hMSCs. Furthermore, the association of a bioinspired material (cHA) with the antibiotic MH resulted in a combined effect of an enhanced osteogenic activity. These findings, together with the antibiofilm activity depicted strengthen the appropriateness of this 3D-printed PLA-Col-MH-cHA scaffold for future use in bone repair. By targeting bone repair while mitigating the typical infections associated to bone implants, our 3D scaffolds deliver an integrated strategy with the combined effects further envisaging an increase in the success rate of bone-implanted devices.

3D printing in cell culture systems and medical applications

3D printing plays an important role in various biomedical research applications including, but not limited to, culture systems and implantable devices. In this review, we discuss recent development in the applications of 3D printing technologies for clinically motivated research, particularly focusing on the fabrication of constructs subsequently incorporated with cells. Applications of this technology include pharmaceutical delivery, bioreactor culture platforms, acellular scaffolds, imaging modalities, and organ-on-a chip systems. Emphasis is placed on technological developments not possible without 3D printing technologies: where traditional manufacturing approaches would be cumbersome to demonstrate research objectives. The clinical applications of 3D printing are rapidly moving from the research to production phases and will certainly continue to grow, with ever increasing numbers of therapies becoming commercialized. The work discussed here holds promise for various applications in structural improvements, drug delivery, and physiology research.

3D printed medicines: A new branch of digital healthcare

Three-dimensional printing (3DP) is a highly disruptive technology with the potential to change the way pharmaceuticals are designed, prescribed and produced. Owing to its low cost, diversity, portability and simplicity, fused deposition modeling (FDM) is well suited to a multitude of pharmaceutical applications in digital health. Favourably, through the combination of digital and genomic technologies, FDM enables the remote fabrication of drug delivery systems from 3D models having unique shapes, sizes and dosages, enabling greater control over the release characteristics and hence bioavailability of medications. In turn, this system could accelerate the digital healthcare revolution, enabling medicines to be tailored to the individual needs of each patient on demand. To date, a variety of FDM 3D printed medical products (e.g. implants) have been commercialised for clinical use. However, within pharmaceuticals, certain regulatory hurdles still remain. This article reviews the current state-of-the-art in FDM technology for medical and pharmaceutical research, including its use for personalised treatments and interconnection within digital health networks. The outstanding challenges are also discussed, with a focus on the future developments that are required to facilitate its integration within pharmacies and hospitals.

3D printed drug delivery and testing systems - a passing fad or the future?

The US Food and Drug Administration approval of the first 3D printed tablet in 2015 has ignited growing interest in 3D printing, or additive manufacturing (AM), for drug delivery and testing systems. Beyond just a novel method for rapid prototyping, AM provides key advantages over traditional manufacturing of drug delivery and testing systems. These includes the ability to fabricate complex geometries to achieve variable drug release kinetics; ease of personalising pharmacotherapy for patient and lowering the cost for fabricating personalised dosages. Furthermore, AM allows fabrication of complex and micron-sized tissue scaffolds and models for drug testing systems that closely resemble in vivo conditions. However, there are several limitations such as regulatory concerns that may impede the progression to market. Here, we provide an overview of the advantages of AM drug delivery and testing, as compared to traditional manufacturing techniques. Also, we discuss the key challenges and future directions for AM enabled pharmaceutical applications.

Three-Dimensional Printing of Medicinal Products and the Challenge of Personalized Therapy

By 3-dimensional (3D) printing, solid objects of any shape are fabricated through layer-by-layer addition of materials based on a digital model. At present, such a technique is broadly exploited in many industrial fields because of major advantages in terms of reduced times and costs of development and production. In the biomedical and pharmaceutical domains, the interest in 3D printing is growing in step with the needs of personalized medicine. Printed scaffolds and prostheses have partly replaced medical devices produced by more established techniques, and more recently, 3D printing has been proposed for the manufacturing of drug products. Notably, the availability of patient-tailored pharmaceuticals would be of utmost importance for children, elderly subjects, poor and high metabolizers, and individuals undergoing multiple drug treatments. 3D printing encompasses a range of differing techniques, each involving advantages and open issues. Particularly, solidification of powder, extrusion, and stereolithography have been applied to the manufacturing of drug products. The main challenge to their exploitation for personalized pharmacologic therapy is likely to be related to the regulatory issues involved and to implementation of production models that may allow to efficiently turn the therapeutic needs of individual patients into small batches of appropriate drug products meeting preset quality requirements.

3D Fabrication of Polymeric Scaffolds for Regenerative Therapy

Recent advances in bioprinting technology have been used to precisely dispense cell-laden biomaterials for the construction of complex 3D functional living tissues or artificial organs. Organ printing and biofabrication provides great potential for the freeform fabrication of 3D living organs using cellular spheroids, biocomposite nanofibers, or bioinks as building blocks for regenerative therapy. Vascularization is often identified as a main technological barrier for building 3D organs in tissue engineering. 3D printing of living tissues starts with potential support of biomaterials to maintain structural integrity and degradation of certain time periods after printing of the scaffolds. Biofabrication is the production of complex living and nonliving biological products from raw materials such as cells, molecules, ECM, and biomaterials. Generally, two basic methods are used for the fabrication of scaffolds such as conventional/traditional fabrication processes and advance fabrication processes for engineering organs. A wide range of polymers and biomaterials are used for the fabrication of scaffolds in tissue engineering applications. 3D additive manufacturing is advancing day-by-day; however, there are various critical challenging factors used for fabricating 3D scaffolds. This review is aimed at understanding the various scaffold fabrication techniques, types of polymers and biomaterials used for the fabrication processes, various fields of applications, and different challenges faced in their fabrication of scaffolds in regenerative therapy.