Extrusion 3D Printing of Paracetamol Tablets from a Single Formulation with Tunable Release Profiles Through Control of Tablet Geometry

The potential of three-dimensional printing for pediatric oral solid dosage forms

Pediatric patients often require individualized dosing of medicine due to their unique pharmacokinetic and developmental characteristics. Current methods for tailoring the dose of pediatric medications, such as tablet splitting or compounding liquid formulations, have limitations in terms of dosing accuracy and palatability. This paper explores the potential of 3D printing as a solution to address the challenges and provide tailored doses of medication for each pediatric patient. The technological overview of 3D printing is discussed, highlighting various 3D printing technologies and their suitability for pharmaceutical applications. Several individualization options with the potential to improve adherence are discussed, such as individualized dosage, custom release kinetics, tablet shape, and palatability. To integrate the preparation of 3D printed medication at the point of care, a decentralized manufacturing model is proposed. In this setup, pharmaceutical companies would routinely provide materials and instructions for 3D printing, while specialized compounding centers or hospital pharmacies perform the printing of medication. In addition, clinical opportunities of 3D printing for dose-finding trials are emphasized. On the other hand, current challenges in adequate dosing, regulatory compliance, adherence to quality standards, and maintenance of intellectual property need to be addressed for 3D printing to close the gap in personalized oral medication.

Development, Evaluation, and Molecular Dynamics Study of Ampicillin-Loaded Chitosan-Hyaluronic Acid Films as a Drug Delivery System

Periodontitis is an inflammatory periodontal disease defined by the progressive loss of tissues surrounding the tooth. Ampicillin is an antibiotic for managing and treating specific bacterial infections, including periodontitis. Periodontal pockets occur due to periodontal disease progression and act as a natural reservoir that is easily reachable for the insertion of a delivery system, and the amount of drug to be released has a major role in the efficiency of treatment of the disease. Polyelectrolyte complexes (PECs), particularly those based on chitosan and hyaluronic acid combinations, offer a promising avenue to overcome the challenges associated with drug delivery. These complexes are both biodegradable and biocompatible, making them an optimal choice for enabling targeted drug delivery. This study centers on developing and assessing the structure and dynamic attributes of a drug-PEC system encompassing ampicillin and chitosan-hyaluronic acid components, which represents a targeted drug delivery system to better alleviate the periodontitis. To achieve this goal, we conducted experiments including weight and drug content uniformity, swelling ındex, drug release %, FT-IR and SEM analyses, and atomistic molecular dynamics simulations on the drug PECs loaded with ampicillin with varying amounts of hyaluronic acid. All simulations and the experimental analysis suggested that increased HA amount resulted in an increase in drug release % and swelling index. The simulation outcomes provide insights into the nature of the drug and PEC interactions alongside transport properties such as drug diffusion coefficients. These coefficients offer valuable insights into the molecular behavior of ampicillin-PEC drug delivery systems, particularly in the context of their application in periodontitis treatment.

Development of a simple paste for 3D printing of drug formulations containing a mesoporous material loaded with a poorly water-soluble drug

Poorly soluble drugs represent a substantial portion of emerging drug candidates, posing significant challenges for pharmaceutical formulators. One promising method to enhance the drug's dissolution rate and, consequently, bioavailability involves transforming them into an amorphous state within mesoporous materials. These materials can then be seamlessly integrated into personalized drug formulations using Additive Manufacturing (AM) techniques, most commonly via Fused Deposition Modeling. Another innovative approach within the realm of AM for mesoporous material-based formulations is semi-solid extrusion (SSE). This study showcases the feasibility of a straightforward yet groundbreaking hybrid 3D printing system employing SSE to incorporate drug-loaded mesoporous magnesium carbonate (MMC) into two different drug formulations, each designed for distinct administration routes. MMC was loaded with the poorly water-soluble drug ibuprofen via a solvent evaporation method and mixed with PEG 400 as a binder and lubricant, facilitating subsequent SSE. The formulation is non-aqueous, unlike most pastes which are used for SSE, and thus is beneficial for the incorporation of poorly water-soluble drugs. The 3D printing process yielded tablets for oral administration and suppositories for rectal administration, which were then analyzed for their dissolution behavior in biorelevant media. These investigations revealed enhancements in the dissolution kinetics of the amorphous drug-loaded MMC formulations. Furthermore, an impressive drug loading of 15.3 % w/w of the total formulation was achieved, marking the highest reported loading for SSE formulations incorporating mesoporous materials to stabilize drugs in their amorphous state by a wide margin. This simple formulation containing PEG 400 also showed advantages over other aqueous formulations for SSE in that the formulations did not exhibit weight loss or changes in size or form during the curing process post-printing. These results underscore the substantial potential of this innovative hybrid 3D printing system for the development of drug dosage forms, particularly for improving the release profile of poorly water-soluble drugs.

Pimobendan controlled release guar gum printlets: Tailoring drug doses for personalised veterinary medicines

Treating chronic heart diseases in dogs is challenging due to variations in mass within and between species. Pimobendan (PBD), a veterinary drug only, is prescribed in specific cases of chronic heart disease in dogs and is available on the market in only a few different doses. Furthermore, the therapy itself is challenging due to the large size of the chewable tablets and the requirement for twice-daily administration. The development of customised and on-demand PBD medicines by three-dimensional (3D) printing has been proposed to circumvent these disadvantages. In this study, we designed controlled-release flavoured printlets containing PBD. We evaluated the use of two natural polymers, guar or xanthan gums, as the main component of the printing inks. Guar gum showed the better rheological behavior and printability by semisolid extrusion. The printlets were produced in three different shapes and sizes to allow dose customisation. Guar gum printlets showed a PBD controlled release profile, regardless of their shape or size. Therefore, we have demonstrated a novel approach for controlling PBD drug release and tailoring the dose by employing a natural polymer to produce 3D-printed tablets. This study represents a significant step towards the development of 3D-printed guar gum controlled-release formulations for veterinary applications.

The role of artificial intelligence in generating original scientific research

Artificial intelligence (AI) is a revolutionary technology that is finding wide application across numerous sectors. Large language models (LLMs) are an emerging subset technology of AI and have been developed to communicate using human languages. At their core, LLMs are trained with vast amounts of information extracted from the internet, including text and images. Their ability to create human-like, expert text in almost any subject means they are increasingly being used as an aid to presentation, particularly in scientific writing. However, we wondered whether LLMs could go further, generating original scientific research and preparing the results for publication. We taskedGPT-4, an LLM, to write an original pharmaceutics manuscript, on a topic that is itself novel. It was able to conceive a research hypothesis, define an experimental protocol, produce photo-realistic images of 3D printed tablets, generate believable analytical data from a range of instruments and write a convincing publication-ready manuscript with evidence of critical interpretation. The model achieved all this is less than 1 h. Moreover, the generated data were multi-modal in nature, including thermal analyses, vibrational spectroscopy and dissolution testing, demonstrating multi-disciplinary expertise in the LLM. One area in which the model failed, however, was in referencing to the literature. Since the generated experimental results appeared believable though, we suggest that LLMs could certainly play a role in scientific research but with human input, interpretation and data validation. We discuss the potential benefits and current bottlenecks for realising this ambition here.

3D Printed Personalized Colon-targeted Tablets: A Novel Approach in Ulcerative Colitis Management

Ulcerative colitis (UC) and Crohn's disease (CD) are two types of idiopathic inflammatory bowel disease (IBD) that are increasing in frequency and incidence worldwide, particularly in highly industrialized countries. Conventional tablets struggle to effectively deliver anti-inflammatory drugs since the inflammation is localized in different areas of the colon in each patient. The goal of 3D printing technology in pharmaceutics is to create personalized drug delivery systems (DDS) that are tailored to each individual's specific needs. This review provides an overview of existing 3D printing processes, with a focus on extrusion-based technologies, which have received the most attention. Personalized pharmaceutical products offer numerous benefits to patients worldwide, and 3D printing technology is becoming more affordable every day. Custom manufacturing of 3D printed tablets provides innovative ideas for developing a tailored colon DDS. In the future, 3D printing could be used to manufacture personalized tablets for UC patients based on the location of inflammation in the colon, resulting in improved therapeutic outcomes and a better quality of life.

Potential Applications and Additive Manufacturing Technology-Based Considerations of Mesoporous Silica: A Review

Nanoporous materials are categorized as microporous (pore sizes 0.2-2 nm), mesoporous (pore sizes 2-50 nm), and macroporous (pore sizes 50-1000 nm). Mesoporous silica (MS) has gained a significant interest due to its notable characteristics, including organized pore networks, specific surface areas, and the ability to be integrated in a variety of morphologies. Recently, MS has been widely accepted by range of manufacturer and as drug carrier. Moreover, silica nanoparticles containing mesopores, also known as mesoporous silica nanoparticles (MSNs), have attracted widespread attention in additive manufacturing (AM). AM commonly known as three-dimensional printing is the formalized rapid prototyping (RP) technology. AM techniques, in comparison to conventional methods, aid in reducing the necessity for tooling and allow versatility in product and design customization. There are generally several types of AM processes reported including VAT polymerization (VP), powder bed fusion (PBF), sheet lamination (SL), material extrusion (ME), binder jetting (BJ), direct energy deposition (DED), and material jetting (MJ). Furthermore, AM techniques are utilized in fabrication of various classified fields such as architectural modeling, fuel cell manufacturing, lightweight machines, medical, and fabrication of drug delivery systems. The review concisely elaborates on applications of mesoporous silica as versatile material in fabrication of various AM-based pharmaceutical products with an elaboration on various AM techniques to reduce the knowledge gap.

Development of 3D-printed vaginal devices containing metronidazole for alternative bacterial vaginosis treatment

Bacterial vaginosis (BV) is an abnormal condition caused by the change of microbiota in the vagina. One of the most common bacteria found in the case of BV is Gardnerella vaginalis, which is categorised as anaerobic facultative bacteria. Currently, the available treatment for BV is the use of antibiotics, such as metronidazole (MTZ), in topical and oral dosage forms. The limitation of the currently available treatment is that multiple administration is required and thus, the patient needs to apply the drug frequently to maintain the drug efficacy. To address these limitations, this research proposed prolonged delivery of MTZ in the form of intravaginal devices made from biodegradable and biocompatible polymers. Semi-solid extrusion (SSE) 3D printing was used to prepare the intravaginal devices. The ratio of high and low molecular weight poly(caprolactone) (PCL) was varied to evaluate the effect of polymer composition on the drug release. The versatility of SSE 3D printer was used to print the intravaginal devices into two different shapes (meshes and discs) and containing two different polymer layers made from PCL and a copolymer of methyl vinyl ether and maleic anhydride (Gantrez™-AN119), which provided mucoadhesive properties. Indeed, this layer made from Gantrez™-AN119 increased ca. 5 times the mucoadhesive properties of the final 3D-printed devices (from 0.52 to 2.57 N). Furthermore, MTZ was homogenously dispersed within the polymer matrix as evidenced by scanning electron microscopy analysis. Additionally, in vitro drug release, and antibacterial activity of the MTZ-loaded intravaginal devices were evaluated. Disc formulations were able to sustain the release of MTZ for 72 h for formulations containing 70/30 and 60/40 ratio of high molecular weight/low molecular weight PCL. On the other hand, the discs containing a 50/50 ratio of high molecular weight/low molecular weight PCL showed up to 9 days of release. However, no significant differences in the MTZ release from the MTZ-loaded meshes (60/40 and 50/50 ratio of high molecular weight/low molecular weight PCL) were found after 24 h. The results showed that the different ratios of high and low molecular weight PCL did not significantly affect the MTZ release. However, the shape of the devices did influence the release of MTZ, showing that larger surface area of the meshes provided a faster MTZ release. Moreover, MTZ loaded 3D-printed discs (5% w/w) were capable of inhibiting the growth of Gardnerella vaginalis. These materials showed clear antimicrobial properties, exhibiting a zone of inhibition of 19.0 ± 1.3 mm. Based on these findings, the manufactured represent a valuable alternative approach to the current available treatment, as they were able to provide sustained release of MTZ, reducing the frequency of administration and thus improving patient compliance.

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

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

3D screen printing technology enables fabrication of oral drug dosage forms with freely tailorable release profiles

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

3D printing of microencapsulated Lactobacillus rhamnosus for oral delivery

3D Printing is an innovative technology within the pharma and food industries that allows the design and manufacturing of novel delivery systems. Orally safe delivery of probiotics to the gastrointestinal tract faces several challenges regarding bacterial viability, in addition to comply with commercial and regulatory standpoints. Lactobacillus rhamnosus CNCM I-4036 (Lr) was microencapsulated in generally recognised as safe (GRAS) proteins, and then assessed for robocasting 3D printing. Microparticles (MP-Lr) were developed and characterised, prior to being 3D printed with pharmaceutical excipients. MP-Lr showed a size of 12.3 ± 4.1 µm and a non-uniform wrinkled surface determined by Scanning Electron Microscopy (SEM). Bacterial quantification by plate counting accounted for 8.68 ±0.6 CFU/g of live bacteria encapsulated within. Formulations were able to keep the bacterial dose constant upon contact with gastric and intestinal pH. Printlets consisted in oval-shape formulations (15 mm × 8 mm × 3.2 mm) of ca. 370 mg of total weight, with a uniform surface. After the 3D printing process, bacterial viability remained even as MP-Lr protected bacteria alongside the process (log reduction of 0.52, p>0.05) in comparison with non-encapsulated probiotic (log reduction of 3.05). Moreover, microparticle size was not altered during the 3D printing process. We confirmed the success of this technology for developing an orally safe formulation, GRAS category, of microencapsulated Lr for gastrointestinal vehiculation.

A Review on Physicochemical Properties of Polymers Used as Filaments in 3D-Printed Tablets

Three-dimensional (3D) printing technology has presently been explored widely in the field of pharmaceutical research to produce various conventional as well as novel dosage forms such as tablets, capsules, oral films, pellets, subcutaneous implants, scaffolds, and vaginal rings. The use of this innovative method is a good choice for its advanced technologies and the ability to make tailored medicine specifically for individual patient. There are many 3D printing systems that are used to print tablets, implants, and vaginal rings. Among the available systems, the fused deposition modeling (FDM) is widely utilized. The FDM has been regarded as the best choice of printer as it shows high potential in the production of tablets as a unit dose in 3D printing medicine manufacturing. In order to design a 3D-printed tablet or other dosage forms, the physicochemical properties of polymers play a vital role. One should have proper knowledge about the polymer's properties so that one can select appropriate polymers in order to design 3D-printed dosage form. This review highlighted the various physicochemical properties of polymers that are currently used as filaments in 3D printing. In this manuscript, the authors also discussed various systems that are currently adopted in the 3D printing.

Sustainable 3D Printing of Oral Films with Tunable Characteristics Using CMC-Based Inks from Durian Rind Wastes

With the growing interest in environmentally friendly and personalized medicines, new concept for combining three-dimensional printing (3DP) with natural-based biomaterials derived from agro-food wastes has emerged. This approach provides sustainable solutions for agricultural waste management and potential for developing of novel pharmaceutical products with tunable characteristics. This work demonstrated the feasibility of fabricating personalized theophylline films with four different structures (Full, Grid, Star, and Hilbert) using syringe extrusion 3DP and carboxymethyl cellulose (CMC) derived from durian rind wastes. Our findings suggested that all the CMC-based inks with shear thinning properties capable of being extruded smoothly through a small nozzle could potentially be used to fabricate the films with various complex printing patterns and high structural fidelity. The results also demonstrated that the film characteristics and release profiles could be easily modified by simply changing the slicing parameters (e.g., infill density and printing pattern). Amongst all formulations, Grid film, which was 3D-printed with 40% infill and a grid pattern, demonstrated a highly porous structure with high total pore volume. The voids between printing layers in Grid film increased theophylline release (up to 90% in 45 min) through improved wetting and water penetration. All findings in this study provide significant insight into how to modify film characteristics simply by digitally changing the printing pattern in slicer software without creating a new CAD model. This approach could help to simplify the 3DP process so that non-specialist users can easily implement it in community pharmacies or hospital on demand.

Development of 3D-printed subcutaneous implants using concentrated polymer/drug solutions

Implantable drug-eluting devices that provide therapeutic cover over an extended period of time following a single administration have potential to improve the treatment of chronic conditions. These devices eliminate the requirement for regular and frequent drug administration, thus reducing the pill burden experienced by patients. Furthermore, the use of modern technologies, such as 3D printing, during implant development and manufacture renders this approach well-suited for the production of highly tuneable devices that can deliver treatment regimens which are personalised for the individual. The objective of this work was to formulate subcutaneous implants loaded with a model hydrophobic compound, olanzapine (OLZ) using robocasting - a 3D-printing technique. The formulated cylindrical implants were prepared from blends composed of OLZ mixed with either poly(caprolactone) (PCL) or a combination of PCL and poly(ethylene)glycol (PEG). Implants were characterised using scanning electron microscopy (SEM), thermal analysis, infrared spectroscopy, and X-ray diffraction and the crystallinity of OLZ in the formulated devices was confirmed. In vitro release studies demonstrated that all the formulations were capable of maintaining sustained drug release over a period of 200 days, with the maximum percentage drug release observed to be c.a. 60 % in the same period.

3D-Printed Fast-Dissolving Oral Dosage Forms via Fused Deposition Modeling Based on Sugar Alcohol and Poly(Vinyl Alcohol)-Preparation, Drug Release Studies and In Vivo Oral Absorption

Three-dimensional printing technology holds marked promise for the pharmaceutical industry and is now under intense investigation. Most research is aimed at a greater efficiency in printing oral dosage forms using powder bed printing or fused deposition modeling (FDM). Oral dosage forms printed by FDM tend to be hard objects, which reduce the risk of cracking and chipping. However, one challenge in printing oral dosage forms via FDM is achieving rapid drug release, because the materials for FDM are basically thermoplastic polymers with slow drug release properties. In this study, we investigated printing a fast-dissolving oral dosage form by adding sugar alcohol to a poly(vinyl alcohol)-based formulation for FDM. Filaments which contain sugar alcohol were successfully prepared, and objects were printed with them as oral dosage forms by FDM. On drug release testing, a printed oral dosage form in a ring shape which contained 55% maltitol showed a more than 85% drug release in 15 min. In vivo oral absorption of this printed oral dosage form in dogs was comparable to that of a conventional fast-dissolving tablet. Of particular interest, the drug release profile and drug amount of the oral dosage forms can be easily controlled by a change in shape using 3D Computer Aided Design. These characteristics will encourage the prevalence of FDM by the pharmaceutical industry, and contribute to the promotion of personalized medicine.

Challenges, current status and emerging strategies in the development of rapidly dissolving FDM 3D-printed tablets: An overview and commentary

Since the approval of a 3D-printed tablet by the FDA in 2015 for marketing, there has been a great interest in 3D printing in the pharmaceutical field for the development of personalized and on-demand medications. Among various 3D printing methods explored for the development of oral solid dosage form like tablet, the fused deposition modeling (FDM) 3D-printing, where the drug-polymer mixtures are first converted into filaments by hot melt extrusion (HME) and then the filaments are printed into tablets using 3D printers by applying computer-aided design principles, has emerged as the most attractive option. However, no FDM 3D-printed tablets have yet been marketed as the technology faces many challenges, such as limited availability of pharmaceutical-grade polymers that can be printed into tablets, low drug-polymer miscibility, the need for high temperature for HME and 3D-printing, and slow drug release rates from tablets. These challenges are discussed in this article with a special focus on drug release rates since FDM 3D-printing usually leads to the preparation of slow-release tablets while the rapid release from dosage forms is often desired for optimal therapeutic outcomes of new drug candidates. Pros and cons of various strategies for the development of rapidly dissolving FDM 3D-printed tablets reported in the literature are reviewed. Finally, two case studies on emerging strategies for the development of rapidly dissolving FDM 3D-printed tablets are presented, where one outlines a systematic approach for formulating rapidly dissolving tablets, and the other describes a novel strategy to increase dissolution rates of drugs from FDM 3D-printed tablets, which at the same time can also increase drug-polymer miscibility and printability of tablets and lower processing temperatures. Thus, this overview and commentary discusses various issues involving the formulation of rapidly dissolving FDM 3D-printed tablets and provides guidance for the development of commercially viable products.

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.

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.

A Novel Preparation Method for Effervescent Tablets of Xianganfang Containing Fresh Juice using a Semi-Solid Extrusion 3D Printer with Three Cartridge Holders

This study aimed to prepare effervescent tablets of traditional Chinese medicine Xianganfang with fresh juice using a semi-solid 3D printer with three cartridge holders to seperate acid and alkali source by drug paste through model design to avoid sticking impact and premature effervescence during the tableting in the conventional preparation process. The powder of Xianganfang including fresh juice of Phyllanthus emblica and licorice extract was obtained by vacuum freeze-drying with 50% mannitol as cryoprotectant. Then, the formulation of 3D-printed effervescent tablets was investigated. Further 5% HPMC hydroalcoholic gel was mixed with sodium bicarbonate and freeze-dried Xianganfang powder to prepare alkali source and drug paste respectively while 30% PVP ethanol solution was mixed with tartaric acid to prepare acid source paste; these three pastes had good printability. The pastes of drug, acid, and alkali were loaded into three syringe cartridges separately and numbered as "3," "5," and "7," according to cartridge holders of the 3D printer, and printed in the order of "537,353,735" for separating acid and alkali by drug to avoid premature effervescence. And the basic printing parameters were optimized. The tablets were evaluated by the appearance, tablet weight variation, hardness, disintegration time, friability, pH, and stability. The physicochemical properties all conformed to the Chinese Pharmacopoeia 2020 edition. The content of the active ingredient gallic acid was 0.769 ± 0.019 mg/g. This study provided a new method to prepare effervescent tablets of traditional Chinese medicine with fresh juice using 3D printing technology.

3D-printed implantable devices with biodegradable rate-controlling membrane for sustained delivery of hydrophobic drugs

Implantable drug delivery systems offer an alternative for the treatments of long-term conditions (i.e. schizophrenia, HIV, or Parkinson’s disease among many others). The objective of the present work was to formulate implantable devices loaded with the model hydrophobic drug olanzapine (OLZ) using robocasting 3D-printing combined with a pre-formed rate controlling membrane. OLZ was selected as a model molecule due to its hydrophobic nature and because is a good example of a molecule used to treat a chronic condition schizophrenia. The resulting implants consisted of a poly(ethylene oxide) (PEO) implant coated with a poly(caprolactone) (PCL)-based membrane. The implants were loaded with 50 and 80% (w/w) of OLZ. They were prepared using an extrusion-based 3D-printer from aqueous pastes containing 36–38% (w/w) of water. The printing process was carried out at room temperature. The resulting implants were characterized by using infrared spectroscopy, scanning electron microscopy, thermal analysis, and X-ray diffraction. Crystals of OLZ were present in the implant after the printing process. In vitro release studies showed that implants containing 50% and 80% (w/w) of OLZ were capable of providing drug release for up to 190 days. On the other hand, implants containing 80% (w/w) of OLZ presented a slower release kinetics. After 190 days, total drug release was ca. 77% and ca. 64% for implants containing 50% and 80% (w/w) of OLZ, respectively. The higher PEO content within implants containing 50% (w/w) of OLZ allows a faster release as this polymer acts as a co-solvent of the drug.

Paliperidone palmitate as model of heat-sensitive drug for long-acting 3D printing application

In this work, two technologies were used to prepare long-acting implantable dosage forms in the treatment of schizophrenia. Hot-melt extrusion (HME) as well as fused deposition modelling (FDM) were used concomitantly to create personalized 3D printed implants. Different formulations were prepared using an amorphous PLA as matrix polymer and different solid-state plasticizers. Paliperidone palmitate (PP), a heat sensitive drug prescribed in the treatment of schizophrenia was chosen as model drug. After extrusion, different formulations were characterized using DSC and XRD. Then, an in vitro dissolution test was carried out to discriminate the formulation allowing a sustained drug release of PP. The formulation showing a sustained drug release of the drug was 3D printed as an implantable dosage form. By modulating the infill, the release profile was related to the proper design of tailored dosage form and not solely to the solubility of the drug. Indeed, different release profiles were achieved over 90 days using only one formulation. In addition, a stability test was performed on the 3D printed implants for 3 months. The results showed the stability of the amorphous state of PP, independently of the temperature as well as the integrity of the matrix and the drug.

3D printing of pharmaceutical oral solid dosage forms by fused deposition: the enhancement of printability using plasticised HPMCAS

3D printing (3DP) by fused deposition modelling (FDM) is one of the most extensively developed methods in additive manufacturing. Optimizing printability by improving feedability, nozzle extrusion, and layer deposition is crucial for manufacturing solid oral dosage forms with desirable properties. This work aimed to use HPMCAS (Affinisol^TM HPMCAS 716) to prepare filaments for FDM-3DP using hot-melt extrusion (HME). It explored and demonstrated the effect of HME-filament composition and fabrication on printability by evaluating thermal, mechanical, and thermo-rheological properties. It also showed that the HME-Polymer filament composition used in FDM-3DP manufacture of oral solid dosage forms provides a tailored drug release profile. HME (HAAKE MiniLab) and FDM-3DP (MakerBot) were used to prepare HME-filaments and printed objects, respectively. Two diverse ways of improving the mechanical properties of HME-filaments were deduced by changing the formulation to enable feeding through the roller gears of the printer nozzle. These include plasticizing the polymer and adding an insoluble structuring agent (talc) into the formulation. Experimental feedability was predicted using texture analysis results was a function of PEG concentration, and glass-transition temperature (T_g) values of HME-filaments. The effect of high HME screw speed (100 rpm) resulted in inhomogeneity of HME-filament, which resulted in inconsistency of the printer nozzle extrudate and printed layers. The variability of the glass-transition temperature (T_g) of the HME-filament supported by scanning electron microscopy (SEM) images of nozzle extrudates and the lateral wall of the printed tablet helped explain this result. The melt viscosity of HPMCAS formulations was investigated using a capillary rheometer. The high viscosity of unplasticized HPMCAS was concluded to be an additional restriction for nozzle extrusion. The plasticization of HPMCAS and the addition of talc into the formulation were shown to improve thickness consistency of printed layers (using homogeneous HME-filaments). A good correlation (R²=0.9546) between the solidification threshold (low-frequency oscillation test determined by parallel-plate rheometer) and T_g of HME-filaments was also established. Drug-loaded and placebo HPMCAS-based formulations were shown to be successfully printed, with the former providing tailored drug release profiles based on variation of internal geometry (infill).

FDM 3D-Printed Sustained-Release Gastric-Floating Verapamil Hydrochloride Formulations with Cylinder, Capsule and Hemisphere Shapes, and Low Infill Percentage

The aim of this work was to design and fabricate fused deposition modeling (FDM) 3D-printed sustained-release gastric-floating formulations with different shapes (cylinder, capsule and hemisphere) and infill percentages (0% and 15%), and to investigate the influence of shape and infill percentage on the properties of the printed formulations. Drug-loaded filaments containing HPMC, Soluplus^® and verapamil hydrochloride were prepared via hot-melt extrusion (HME) and then used to print the following gastric-floating formulations: cylinder-15, capsule-0, capsule-15, hemisphere-0 and hemisphere-15. The morphology of the filaments and the printed formulations were observed by scanning electron microscopy (SEM). The physical state of the drugs in the filaments and the printed formulations were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The printed formulations were evaluated in vitro, including the weight variation, hardness, floating time, drug content and drug release. The results showed that the drug-loaded filament prepared was successful in printing the gastric floating formulations. Verapamil hydrochloride was proved thermally stable during HME and FDM, and in an amorphous state in the filament and the printed formulations. The shape and infill percentage of the printed formulations effected the hardness, floating time and in vitro drug release.

Feasibility of developing hospital preparation by Semisolid extrusion 3D printing: Personalized Amlodipine Besylate chewable tablets

Semisolid extrusion (SSE) 3D printing is an emerging technology in personalized medicine. To address clinical multi-dose requirements, SSE has been explored to manufacture new preparations. In this study, amlodipine besylate (AMB) was the model drug, and SSE was the pharmaceutical strategy. We developed semisolids suitable for SSE and AMB chewable tablets with six strengths (1.5-5 mg) to meet the needs of 2-16-year-old patients. First, the semisolid extrudability was evaluated by texture analyzer, and then the amounts of carboxymethyl cellulose sodium, sodium starch glycolate, and glycerin were optimized by full factorial design. Then, rheological tests were performed to evaluate the properties of the semisolid and the effect of starch sodium glycolate on printability. Finally, the amount of corrigents was optimized using an electronic tongue. Laboratory amplified semisolids and 3D printed tablets can be stored for a few months, and the whole SSE process had no effect on crystal type. This study validated the feasibility of SSE 3D printing, and tablets with appropriate taste and cartoon appearance can meet or even exceed the traditional preparations. Our study provides a new strategy for multi-dose solid preparations and effectively addresses the need for personalized amlodipine medicine.

Coupling of Fused Deposition Modeling and Inkjet Printing to Produce Drug Loaded 3D Printed Tablets

In the current study, we have coupled Fused Deposition Modelling (FDM) for the fabrication of plain polyvinyl alcohol (PVA) tablets followed by dispensing of minoxidil ethanolic solutions using inkjet printing. The use of a drop-on-solid printing approach facilitates an accurate and reproducible process while it controls the deposition of the drug amounts. For the purpose of the study, the effect of the solvent was investigated and minoxidil ink solutions of ethanol 70% v/v (P70) or absolute ethanol (P100) were applied on the plain PVA tablets. Physicochemical characterization showed that solvent miscibility with the polymer substrate plays a key role and can lead to the formation of drug crystals on the surface or drug absorption in the polymer matrix. The produced minoxidil tablets showed sustained release profiles or initial bursts strongly affected by the solvent grade used for dispensing the required dose on drug loaded 3D printed tablets. This paradigm demonstrates that the coupling of FDM and inkjet printing technologies could be used for rapid development of personalized dosage forms.

Influence of Print Settings on the Critical Quality Attributes of Extrusion-Based 3D-Printed Caplets: A Quality-by-Design Approach

Extrusion-based 3D-printing is an easy-to-use, cheap manufacturing technique that could be used to produce tailored precision medicines. The technique has an almost unlimited versatility since a multitude of print parameters can easily be adapted. Unfortunately, little is known of the effect of these print parameters on the critical quality attributes of the resulting printlets. In this study, practical guidelines and means to adapt certain parameters in order to achieve the desired outcome (e.g., acceptable visual quality and flexible dosing) are stipulated for medical 3D-printing using a design-of-experiments approach. The current study aims at elucidating the effect of five print parameters (infill, overlap, number of shells, layer height and layer pattern) on the mechanical properties, dimensions, weight, porosity and dissolution characteristics of a fixed-size caplet consisting of Eudragit EPO (69.3%), Polyox WSR N10 (29.7%) and zolpidem hemitartrate (1%). In terms of the mechanical properties, 3D-printed caplets possessed anisotropy where the vertical compression strength and Brinell hardness exceeded the diametral strength. In general, all 3D-printed caplets possessed acceptable mechanical strength except for a small region of the knowledge space. Dimensional analysis revealed small, statistical significant differences between different runs, although the clinical relevance of this variation is likely negligible. The weight or dose of a caplet can be varied mainly using the infill and overlap and, to a lesser extent, via the layer height and number of shells. The impact on porosity was complicated as this was influenced by many factors and their interactions. Infill was the only statistically relevant factor influencing the dissolution rate of the current formulation. This study unravels the importance of the print parameter overlap, which is a regularly neglected parameter. We also discovered that small dose variations while maintaining the same dissolution profile were possible via modifying the overlap or number of shells. However, large dose variations without affecting the dissolution behaviour could only be accomplished by size modifications of the printlet.

Manufacturing and Examination of Vaginal Drug Delivery System by FDM 3D Printing

Vaginal drug delivery systems can provide a long-term and constant liberation of the active pharmaceutical ingredient even for months. For our experiment, FDM 3D printing was used to manufacture the vaginal ring samples from thermoplastic polyurethane filament, which enables fast manufacturing of complex, personalized medications. 3D printing can be an excellent alternative instead of industrial manufacturing, which is complicated and time-consuming. In our work, the 3D printed vaginal rings were filled manually with jellified metronidazole or chloramphenicol for the treatment of bacterial vaginosis. The need for manual filling was certified by the thermogravimetric and heatflow assay results. The manufactured samples were analyzed by an Erweka USP type II Dissolution Apparatus, and the dissolution profile can be distinguished based on the applied jellifying agents and the API's. All samples were considered non-similar based on the pairwise comparison. The biocompatibility properties were determined by prolonged MTT assay on HeLa cells, and the polymer could be considered non-toxic. Based on the microbiological assay on E. coli metronidazole and chitosan containing samples had bactericidal effects while just metronidazole or just chitosan containing samples bacteriostatic effect. None of these samples showed a fungistatic or fungicide effect against C. albicans. Based on our results, we successfully manufactured 3D printed vaginal rings filled with jellified metronidazole.

3D-Printed Oral Dosage Forms: Mechanical Properties, Computational Approaches and Applications

The aim of this review is to present the factors influencing the mechanical properties of 3D-printed oral dosage forms. It also explores how it is possible to use specific excipients and printing parameters to maintain the structural integrity of printed drug products while meeting the needs of patients. Three-dimensional (3D) printing is an emerging manufacturing technology that is gaining acceptance in the pharmaceutical industry to overcome traditional mass production and move toward personalized pharmacotherapy. After continuous research over the last thirty years, 3D printing now offers numerous opportunities to personalize oral dosage forms in terms of size, shape, release profile, or dose modification. However, there is still a long way to go before 3D printing is integrated into clinical practice. 3D printing techniques follow a different process than traditional oral dosage from manufacturing methods. Currently, there are no specific guidelines for the hardness and friability of 3D printed solid oral dosage forms. Therefore, new regulatory frameworks for 3D-printed oral dosage forms should be established to ensure that they meet all appropriate quality standards. The evaluation of mechanical properties of solid dosage forms is an integral part of quality control, as tablets must withstand mechanical stresses during manufacturing processes, transportation, and drug distribution as well as rough handling by the end user. Until now, this has been achieved through extensive pre- and post-processing testing, which is often time-consuming. However, computational methods combined with 3D printing technology can open up a new avenue for the design and construction of 3D tablets, enabling the fabrication of structures with complex microstructures and desired mechanical properties. In this context, the emerging role of computational methods and artificial intelligence techniques is highlighted.

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

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

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

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

3D printed furosemide and sildenafil tablets: Innovative production and quality control

Three-dimensional (3D) printing of pharmaceuticals has the potential to revolutionise personalised medicine but is as yet largely unexplored. A proof-of-concept study of a novel heated, piston-driven semi-solid extrusion 3D printer was performed by producing furosemide and sildenafil tablets for paediatric patients. The average weight of the tablets was 141.1 mg (RSD 1.26%). The acceptance values of the content uniformity were 4.2-10.6 (concentration RSD 0.41-0.63%), 4.8-8.9 (concentration RSD 0.76-0.97%) and 6.6-9.2 (concentration RSD 0.94-1.44%) for furosemide 2 mg, 10 mg and sildenafil 4 mg, respectively. The dissolution rate limiting step was the dissolving and eroding of the tablet matrix and showed an immediate release. The tablets complied to the requirements of the European Pharmacopoeia (EP) for uniformity of mass (EP 2.9.5), content uniformity (EP 2.9.40) and conventional release (EP 2.9.3). While they complied, not all of these quality tests for tablets might be suitable for 3D printed tablets due to the layering of the tablets and the small batch production. To assess adequate layer adhesion adjusted friability (EP 2.9.7) and resistance to crushing (EP 2.9.8) tests are proposed.

Effects of porosity on drug release kinetics of swellable and erodible porous pharmaceutical solid dosage forms fabricated by hot melt droplet deposition 3D printing

3D printing has the unique ability to produce porous pharmaceutical solid dosage forms on-demand. Although using porosity to alter drug release kinetics has been proposed in the literature, the effects of porosity on the swellable and erodible porous solid dosage forms have not been explored. This study used a model formulation containing hypromellose acetate succinate (HPMCAS), polyethylene oxide (PEO) and paracetamol and a newly developed hot melt droplet deposition 3D printing method, Arburg plastic free-forming (APF), to examine the porosity effects on in vitro drug release. This is the first study reporting the use of APF on 3D printing porous pharmaceutical tablets. With the unique pellet feeding mechanism of APF, it is important to explore its potential applications in pharmaceutical additive manufacturing. The pores were created by altering the infill percentages (%) of the APF printing between 20 and 100% to generate porous tablets. The printing quality of these porous tablets was examined. The APF printed formulation swelled in pH 1.2 HCl and eroded in pH 6.8 PBS. During the dissolution at pH 1.2, the swelling of the printing pathway led to the gradual decreases in the open pore area and complete closure of pores for the tablets with high infills. In pH 6.8 buffer media, the direct correlation between drug release rate and infills was observed for the tablets printed with infill at and less than 60%. The results revealed that drug release kinetics were controlled by the complex interplay of the porosity and dynamic changes of the tablets caused by swelling and erosion. It also implied the potential impact of fluid hydrodynamics on the in vitro data collection and interpretation of porous solids.

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

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

Predicting drug release from diazepam FDM printed tablets using deep learning approach: Influence of process parameters and tablet surface/volume ratio

The aim of this study was to apply artificial neural networks as deep learning tools in establishing a model for understanding and prediction of diazepam release from fused deposition modeling (FDM) printed tablets. Diazepam printed tablets of various shapes were created by a computer-aided design (CAD) program and prepared by fused deposition modeling using previously prepared polyvinyl alcohol/diazepam filaments via hot-melt extrusion. The surface to volume ratio (SA/V) for each shape was calculated. Printing parameters were varied including infill density (20%, 70% and 100%) and infill pattern (line and zigzag). Influence of tablet SA/V ratio and printing parameters (infill density and infill pattern) on the release of diazepam from printed tablets were modeled using self-organizing maps (SOM) and multi-layer perceptron (MLP). SOM as an unsupervised neural network was used for visualizing interrelation among the data, whereas MLP was used for the prediction of drug release properties. MLP had three layers (with structure 2-3-5) and was trained using back propagation algorithm. Input parameters for the modeling were: infill density and SA/V ratio; while output parameters were percent of drug release in five time points. The data set for network training was divided into training, validation and test sets. The dissolution rate increased with higher SA/V ratio, lower infill density (less than 50%) and zigzag infill pattern. The established ANN model was tested; calculated f 2 factors for two tested formulations (70.24 and 77.44) showed similarity between experimentally observed and predicted drug release profiles. Trained MLP network was able to predict drug release behavior as a function of infill density and SA/Vol ratio, as established design space for formulated 3D printed diazepam tablets.

3DP Printing of Oral Solid Formulations: A Systematic Review

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

Customizable drug tablets with constant release profiles via 3D printing technology

Medicine should ideally be personalized as each individual has his/her own unique biological, physical, and medical dispositions. Medicine can be personalized by customizing drug tablets with the specific drug dosages, release durations, and combinations of multiple drugs. This study presents a method for fabricating drug tablets with customizable dosages, durations, and combinations of multiple drugs by using the 3D printing technology. The method focuses on fabricating customizable drug tablets with a very simple structure for delivering the constant release profile due to its importance in treatment (i.e., the drug may produce side effects if too much is released andmay not have therapeutic value is too little is released). The method is simple: it involves first printing a template using the 3D printer and fabricating the drug tablet via the template. The tablets are customized by varying the amount of excipient used, the height of the tablet, and the numberand amount of drugs used. Three different common drugs (i.e., paracetamol, phenylephrine HCl and diphenhydramine HCl) and FDA-approved excipients are studied. The simplicity of the structure of the tablet and method via templating allows the fabrication of these fully customizable drug tablets to be easily performed, low-cost, efficient, and safe for consumption. These features enable the customizable tablets to be made widely accessible to the public; hence, the concept of personalized medicine can be realized.

3D printed polymeric drug-eluting implants

An extrusion-based 3D printer has been used for the manufacturing of sustained drug release poly(ε-caprolactone) (PCL) implants. Such implants can address issues of reduced patient compliance due to the necessary frequent administration of conventional drug delivery systems, such as tablets, capsules and solutions. The selected model drug for this study was lidocaine. Polycaprolactone core-shell implants, as well as polymeric implants with no barrier shell were printed with different drug loading, without the addition of solvents or further excipients. Scanning Electron Microscopy (SEM) analysis revealed the structural integrity of the printed formulations, while Differential Scanning Calorimetry (DSC), X-Ray Diffraction (XRD) and Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR) were used to detect potential chemical interactions or modifications. Raman spectroscopy was also used to study material distribution in the prints. The drug release rate of the differently printed formulations was evaluated using a USP4 flow-through cell apparatus. All printed implants demonstrated sustained lidocaine release and the effectiveness of the PCL barrier in this regard. The Korsmeyer-Peppas model was suggested as the best fit to drug release profiles for all the produced implants. This work demonstrates that hot-melt extrusion-based 3D printing is a robust and promising technology for the production of personalisable drug-eluting implants.

Additive Manufacturing of Oral Tablets: Technologies, Materials and Printed Tablets

Additive manufacturing (AM), also known as three-dimensional (3D) printing, enables fabrication of custom-designed and personalized 3D constructs with high complexity in shape and composition. AM has a strong potential to fabricate oral tablets with enhanced customization and complexity as compared to tablets manufactured using conventional approaches. Despite these advantages, AM has not yet become the mainstream manufacturing approach for fabrication of oral solid dosage forms mainly due to limitations of AM technologies and lack of diverse printable drug formulations. In this review, AM of oral tablets are summarized with respect to AM technology. A detailed review of AM methods and materials used for the AM of oral tablets is presented. This article also reviews the challenges in AM of pharmaceutical formulations and potential strategies to overcome these challenges.

3D Printing as a Promising Tool in Personalized Medicine

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

In Vitro Tests of FDM 3D-Printed Diclofenac Sodium-Containing Implants

One of the most promising emerging innovations in personalized medication is based on 3D printing technology. For use as authorized medications, 3D-printed products require different in vitro tests, including dissolution and biocompatibility investigations. Our objective was to manufacture implantable drug delivery systems using fused deposition modeling, and in vitro tests were performed for the assessment of these products. Polylactic acid, antibacterial polylactic acid, polyethylene terephthalate glycol, and poly(methyl methacrylate) filaments were selected, and samples with 16, 19, or 22 mm diameters and 0%, 5%, 10%, or 15% infill percentages were produced. The dissolution test was performed by a USP dissolution apparatus 1. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide dye (MTT)-based prolonged cytotoxicity test was performed on Caco-2 cells to certify the cytocompatibility properties. The implantable drug delivery systems were characterized by thermogravimetric and heatflow assay, contact angle measurement, scanning electron microscopy, microcomputed tomography, and Raman spectroscopy. Based on our results, it can be stated that the samples are considered nontoxic. The dissolution profiles are influenced by the material properties of the polymers, the diameter, and the infill percentage. Our results confirm the potential of fused deposition modeling (FDM) 3D printing for the manufacturing of different implantable drug delivery systems in personalized medicine and may be applied during surgical interventions.