Formulation of 3D Printed Tablet for Rapid Drug Release by Fused Deposition Modeling: Screening Polymers for Drug Release, Drug-Polymer Miscibility and Printability

The comprehensive review on 3D printing- pharmaceutical drug delivery and personalized food and nutrition

Three-dimensional printing is one of the emerging technologies that is gaining interest from the pharmaceutical industry as it provides an opportunity to customize drugs according to each patient's needs. Combining different active pharmaceutical ingredients, using different geometries, and providing sustained release enhances the effectiveness of medicine. One of the most innovative uses of 3D printing is producing fabrics, medical devices, medical implants, orthoses, and prostheses. This review summarizes the various 3D printing techniques such as stereolithography, inkjet printing, thermal inkjet printing, fused deposition modelling, extrusion printing, semi-solid extrusion printing, selective laser sintering, and hot-melt extrusion. Also, discusses the drug relies profile and its mechanisms, characteristics, and applications of the most common types of 3D printed API formulations and its recent development. Here, Authors also, summarizes the central flow of 3D food printing process and knowledge extension toward personalized nutrition.

PVA-based formulations as a design-technology platform for orally disintegrating film matrices

In the majority of pharmaceutical applications, polymers are employed extensively in a diverse range of pharmaceutical products, serving as indispensable components of contemporary solid oral dosage forms. A comprehensive understanding of the properties of polymers and selection the appropriate methods of characterization is essential for the design and development of novel drug delivery systems and manufacturing processes. Orally disintegrating film (ODF) formulations are considered to be a potential substitute to traditional oral dosage forms and an alternative method of drug administration for children and uncooperative adult patients, including those with swallowing difficulties. A multitude of pharmaceutical formulations with varying mechanical and biopharmaceutical properties have emerged from the modification of the original polymeric bulk. Here we propose different formulation approaches, i.e. solvent casting (SC), 3D printing (3DP), electrospinning (ES), and lyophilization (LP) that enabled us to adjust the disintegration time and the release profile of poorly water soluble haloperidol (HAL, BCS class II) from PVA (polyvinyl alcohol) based polymer films while maintaining similar hydrogel composition. In this study, the solubility of haloperidol in aqueous solution was improved by the addition of lactic acid. The prepared films were evaluated for their morphology (SEM, micro-CT), physicochemical and biopharmaceutical properties. TMDSC, TGA and PXRD were employed for extensive thermal and structural analysis of fabricated materials and their stability. These results allowed us to establish correlations between preparation technology, structural characteristics and properties of PVA films and to adapt the suitable manufacturing technique of the ODFs to achieve appropriate HAL dissolution behaviour.

Role of rheology in formulation and process design of hot melt extruded amorphous solid dispersions

Hot melt extrusion (HME) has been widely used as a continuous and highly flexible pharmaceutical manufacturing process for the production of a variety of dosage forms. In particular, HME enables preparation of amorphous solid dispersions (ASDs) which can improve bioavailability of poorly water-soluble drugs. The rheological properties of drug-polymer mixtures can significantly influence the processability of drug formulations via HME and eventually the end-use product properties such as physical stability and drug release. The objective of this review is to provide an overview of various rheological techniques and properties that can be used to evaluate the flow behavior and processability of the drug-polymer mixtures as well as formulation characteristics such as drug-polymer interactions, miscibility/solubility, and plasticization to improve the HME processability. An overview of the thermodynamics and kinetics of ASD processing by HME is also provided, as well as aspects of scale-up and process modeling, highlighting rheological properties on formulation design and process development. Overall, this review provides valuable insights into critical rheological properties which can be used as a predictive tool to optimize the HME processing conditions.

Investigation of Rheological Properties of Molten Materials for Dripping Pills Based on Imaging Monitoring

INTRODUCTION

Rheological properties, as critical material attributes (CMAs) of solid dispersion drugs such as dripping pills, affect the melting, dispersion, and solidification. Therefore, characterization and assessments of rheological properties in the pharmaceutical process are important in enhancing drug stability and bioavailability.

OBJECTIVES

The study aimed to develop a method for analyzing the rheology of molten materials, assessing their consistency and how rheological properties affect the dripping process and pills quality.

MATERIALS AND METHODS

The rheological behavior of molten materials composed of Ginkgo biloba leaf extract (GBE) and polyethylene glycol (PEG) 4000 was characterized. Batch consistency of molten materials was evaluated. Image monitoring technology was utilized to capture and process images of the droplet formation process. We established the relationship between the rheological properties of molten materials and various attributes.

RESULTS

The quality consistency of molten materials was evaluated, with 12 batches showing similarity above 0.8. The MLR models showed strong correlations (R2 > 0.80) between rheological properties and evaluation attributes. The rheological properties, including consistency coefficient, flow index, and viscosity at 80°C, were identified as critical rheological properties of the molten materials. Rheological property differences of molten materials have an impact on the morphology of droplet and quality performance.

CONCLUSION

A rheological method was established, enabling quality consistency evaluation of molten materials in dripping pills. This study revealed the influence of rheological properties on droplet formation process and dripping pills quality, providing a reference for researches on material attributes control of other traditional Chinese medicine dripping pills.

Dosage by design - 3D printing individualized cabozantinib tablets with immediate release

Production of patient-specific dosage forms is important to improve patient adherence and effectiveness while reducing the prevalence and severity of adverse effects. Due to its possibility of rapid prototyping 3D printing can be used to produce individual dosages while utilizing techniques such as hot melt extrusion to increase the bioavailability of poorly soluble drugs. In this work, Parteck MXP and Kollicoat IR were used as water-soluble polymer bases for formulation development for 3D printing of various dosages incorporating cabozantinib while enabling immediate release. The effect of tablet design and the excipients sorbitol, croscarmellose sodium, and sodium starch glycolate was investigated for this goal. A way to calculate the size of tablets for predetermined dosages is proposed to enable the printing of individual strengths from one formulation. Rheological data were collected to deepen the understanding of the role of melt viscosity in 3D printing and hot melt extrusion processes. The production of immediate-release cabozantinib tablets containing every therapeutically relevant dosage in a single unit produced by two-step 3D printing was realized.

3D-printed immediate release solid dosage forms: a patent evaluation of US11622940B2

Three-dimensional (3D) printing is one of the most flexible technologies for preparing tablets, offering controlled drug release profiles. The current patent describes the preparation of immediate-release 3D-printed tablets of hydrochlorothiazide to improve disintegration and dissolution profile. The patent involves the preparation of drug-loaded filament via hot-melt extrusion and utilizing the same filaments for printing 3D-printed tablets using fused deposition modeling. The tablets were printed with different shapes and sizes by incorporating channels within the tablet spaces, termed as gaplets. The introduction of channels within the tablet design improves the disintegration and dissolution profile of the drug significantly. The morphological characteristic of 3D-printed tablets was studied by using scanning electron microscopy and revealed the presence of gaplets in the tablets.

Amorphous solid dispersion of a binary formulation with felodipine and HPMC for 3D printed floating tablets

This study focuses on the combination of three-dimensional printing (3DP) and amorphous solid dispersion (ASD) technologies for the manufacturing of gastroretentive floating tablets. Employing hot melt extrusion (HME) and fused deposition modeling (FDM), the study investigates the development of drug-loaded filaments and 3D printed (3DP) tablets containing felodipine as model drug and hydroxypropyl methylcellulose (HPMC) as the polymeric carrier. Prior to fabrication, solubility parameter estimation and molecular dynamics simulations were applied to predict drug-polymer interactions, which are crucial for ASD formation. Physical bulk and surface characterization complemented the quality control of both drug-loaded filaments and 3DP tablets. The analysis confirmed a successful amorphous dispersion of felodipine within the polymeric matrix. Furthermore, the low infill percentage and enclosed design of the 3DP tablet allowed for obtaining low-density systems. This structure resulted in buoyancy during the entire drug release process until a complete dissolution of the 3DP tablets (more than 8 h) was attained. The particular design made it possible for a single polymer to achieve a zero-order controlled release of the drug, which is considered the ideal kinetics for a gastroretentive system. Accordingly, this study can be seen as an advancement in ASD formulation for 3DP technology within pharmaceutics.

Personalized nutrition with 3D-printed foods: A systematic review on the impact of different additives

Three-dimensional (3D) printing is one of the world's top novel technologies in the food industry due to the production of food in different conditions and places (restaurants, homes, catering, schools, for dysphagia patients, and astronauts' food) and the production of personalized food. Nowadays, 3D printers are used in the main food industries, including meat, dairy, cereals, fruits, and vegetables, and have been able to produce successfully on a small scale. However, due to the expansion of this technology, it has challenges such as high-scale production, selection of printable food, formulation optimization, and food production according to the consumer's opinion. Food additives (gums, enzymes, proteins, starches, polyphenols, spices, probiotics, algae, edible insects, oils, salts, vitamins, flavors, and by-products) are one of the main components of the formulation that can be effective in food production according to the consumer's attitude. Food additives can have the highest impact on textural and sensory characteristics, which can be effective in improving consumer attitudes and reducing food neophobia. Most of the 3D-printed food cannot be printed without the presence of hydrocolloids, because the proper flow of the selected formulation is one of the key factors in improving the quality of the printed product. Functional additives such as probiotics can be useful for specific purposes and functional food production. Food personalization for specific diseases with 3D printing technology requires a change in the formulation, which is closely related to the selection of correct food additives. For example, the production of 3D-printed plant-based steaks is not possible without the presence of additives, or the production of food for dysphagia patients is possible in many cases by adding hydrocolloids. In general, additives can improve the textural, rheological, nutritional, and sensory characteristics of 3D printed foods; so, investigating the mechanism of the additives on all the characteristics of the printed product can provide a wide perspective for industrial production and future studies.

Application of 3D printing technology for the development of dose adjustable geriatric and pediatric formulation of celecoxib

Developing safe and effective formulations for the geriatric and pediatric population is a challenging task due to issues of swallowability and palatability. The lack of standardized procedures for pediatric formulations further complicates the process. Manipulating adult formulations for children can lead to suboptimal efficacy and safety concerns. To overcome these challenges, minitablets or spinklets are preferred for the geriatric and pediatric population due to their smaller size and flexible dose adjustment. The aim of this study is the development of a 3D printed spinklets formulation of celecoxib, a nonsteroidal anti-inflammatory drug, using hot melt extrusion to address the limitations of traditional manufacturing methods. Three different formulations of celecoxib were prepared using Poly-2-ethyl-tetra-oxazoline (Aquazol) with and without surfactant. Subsequently, the mechanical properties and solubility of the drug-loaded filaments were evaluated. Solid state characterization confirmed the drug conversion into an amorphous form during the extrusion process, Computer-aided design software facilitate sprinklets design for fused deposition modeling and scanning electron microscopy assess the surface morphology. Sophorolipids plasticize better than TPGS, resulting in lowering processing temperatures during melt extrusion. In vitro drug release showed successful enhancements in the dissolution of oral medications for pediatric patients, considering their distinctive physiological characteristics. Overall, this study demonstrates the successful development of PEtOx-based 3D printed celecoxib sprinklets by coupling hot-melt extrusion and 3D printing technology. Future exploration holds the potential to revolutionize pharmaceutical production and advance personalized medication formulations.

3D printing processes in precise drug delivery for personalized medicine

With the advent of personalized medicine, the drug delivery system will be changed significantly. The development of personalized medicine needs the support of many technologies, among which three-dimensional printing (3DP) technology is a novel formulation-preparing process that creates 3D objects by depositing printing materials layer-by-layer based on the computer-aided design method. Compared with traditional pharmaceutical processes, 3DP produces complex drug combinations, personalized dosage, and flexible shape and structure of dosage forms (DFs) on demand. In the future, personalized 3DP drugs may supplement and even replace their traditional counterpart. We systematically introduce the applications of 3DP technologies in the pharmaceutical industry and summarize the virtues and shortcomings of each technique. The release behaviors and control mechanisms of the pharmaceutical DFs with desired structures are also analyzed. Finally, the benefits, challenges, and prospects of 3DP technology to the pharmaceutical industry are discussed.

Correlating mechanical and rheological filament properties to processability and quality of 3D printed tablets using multiple linear regression

Filament formulation for FDM is a challenging and time-consuming process. Several pharmaceutical polymers are not feedable on their own. Due to inadequate filament formulation, 3D printed tablets can also exhibit poor uniformity of tablet attributes. To better understand filament formulation process, 23 filaments were prepared with the polymer mixing approach. To yield processable filaments, brittle and pliable polymers were combined. A 20 % addition of a pliable polymer to a brittle one resulted in filament processability and vice versa. Predictive statistical models for filament processability and uniformity of tablet attributes were established based on the mechanical and rheological properties of filaments. 15 input variables were correlated to 9 responses, which represent filament processability and tablet properties, by using multiple linear regression approach. Filament stiffness, assessed by indentation, and its square term were the only variables that determined the filament's feedability. However, the resulting model is equipment-specific since different feeding mechanism exert different forces on the filaments. Additional models with good predictive power (R2pred > 0.50) were established for tablet width uniformity, drug release uniformity, tablet disintegration time uniformity and occurrence of disintegration, which are equipment-independent outputs. Therefore, the obtained model outcomes could be used in other research endeavours.

Bibliometric Analysis-Based Review of Fused Deposition Modeling 3D Printing Method (1994-2020)

This study aimed at the detailed bibliometric analysis (BA) of fused deposition modeling (FDM) to understand the trend and research area. Web of Science database was used for extracting data using keywords, and 2793 documents were analyzed. From the analysis, the most influential and productive authors, countries, sources, and so on were identified and corresponding interrelations were represented by a three-field plot. Lotka's law was derived for author productivity and its reliability was verified by the Kolmogorov-Smirnov (K-S) test. Bradford's law was used for identifying the core sources contributing to the field of FDM. From the trend topic analysis, it was found that initially the research was focused upon removing error related to deposition as well as part orientation, but with the course of time, it diversified to include topics such as optimization of printing parameters, materials, and applications. Based on the inferences from BA, the article also discusses on current research trend and highlights certain future areas for research work.

3D-printed prednisolone phosphate suppositories with tunable dose and rapid release for the treatment of inflammatory bowel disease

Established medicines are often not tailored to the needs of the pediatric population, causing difficulties with administration or dosing. Three-dimensional (3D) printing technology allows novel approaches for compounding of personalized medicine, as is exemplified in this study for the automated compounding of rectal preparations for children. We investigated the material requirements to print prednisolone phosphate-loaded suppositories with tunable dose and rapid drug release for the treatment of inflammatory bowel diseases. Three formulations containing 4 % w/w prednisolone sodium phosphate (PSP) and different amounts of hydroxypropyl cellulose (HPC) and mannitol as excipients were printed as suppositories with a fused deposition modeling (FDM) 3D-printer. Dissolution studies showed that the PSP release rate was increased when higher weight fractions of mannitol were added as a pore former, with 90 % drug release within 30 min for mannitol 48 % w/w. We further printed suppositories with 48 % mannitol with different infill densities and dimensions to tune the dose. Our findings demonstrated that 3D-printed suppositories with PSP doses ranging from 6 to 30 mg could be compounded without notably affecting the dissolution kinetics, ensuring equivalent therapeutic efficacies for different doses.

Impact of drug load and polymer molecular weight on the 3D microstructure of printed tablets

This study investigates the influence of drug load and polymer molecular weight on the structure of tablets three-dimensionally (3D) printed from the binary mixture of prednisolone and hydroxypropyl methylcellulose (HPMC). Three different HPMC grades, (AFFINISOLTM HPMC HME 15LV, 90 Da (HPMC 15LV); 100LV, 180 Da (HPMC 100LV); 4M, 500 Da (HPMC 4M)), which are suitable for hot-melt extrusion (HME), were used in this study. HME was used to fabricate feedstock material, i.e., filaments, at the lowest possible extrusion temperature. Filaments of the three HPMC grades were prepared to contain 2.5, 5, 10 and 20 % (w/w) prednisolone. The thermal degradation of the filaments was studied with thermogravimetric analysis, while solid-state properties of the drug-loaded filaments were assessed with the use of X-ray powder diffraction. Prednisolone in the freshly extruded filaments was determined to be amorphous for drug loads up to 10%. It remained physically stable for at least 6 months of storage, except for the filament containing 10% drug with HPMC 15LV, where recrystallization of prednisolone was detected. Fused deposition modeling was utilized to print honeycomb-shaped tablets from the HME filaments of HPMC 15LV and 100LV. The structural characteristics of the tablets were evaluated using X-ray microcomputed tomography, specifically porosity and size of structural elements were investigated. The tablets printed from HPMC 15LV possessed in general lower total porosity and pores of smaller size than tablets printed from the HPMC 100LV. The studied drug loads were shown to have minor effect on the total porosity of the tablets, though the lower the drug load was, the higher the variance of porosity along the height of the tablet was observed. It was found that tablets printed with HPMC 15LV showed higher structural similarity with the virtually designed model than tablets printed from HPMC 100LV. These findings highlight the relevance of the drug load and polymer molecular weight on the microstructure and structural properties of 3D printed tablets.

Facile fabrication of an extended-release tablet of Ticagrelor using three dimensional printing technology

The objective of the study was to fabricate tailored extended-release tablets of blood thinner Ticagrelor as once-daily dosing using additive manufacturing for better compliance in heart failure therapy. The solid work design of the tablet was printed using hot melt extrusion (HME) based 3D printing by optimized mixture of Eudragit RS-100, plasticizer and drug for producing extrudable and printable filaments. FTIR and TGA results showed no covalent interaction among ingredients and no decomposition during HME process, respectively. Friability, weight variation, assay and content uniformity tests met USP requirements, while the mean hardness of the tablets was calculated in a value between 40 and 50 kg. According to DSC and XRD results, the crystallinity state of the Ticagrelor was converted to an amorphous one in the tablet matrix. Smooth surfaces with multiple deposited layers were observed using SEM. In comparison, the maximum Ticagrelor release of 100% after 120 min from Brilinta® tablets was decreased to 97% in 400 min from the 3D tablet at infill of 90%. Korsmeyer-Peppas kinetic model showed the drug release mechanism is affected by diffusion and swelling. In general, fabrication of the extended-release 3D printed tablet of Ticagrelor using HME-based-additive manufacturing has the potential to provide specific doses with tailored kinetic release for personalized medicine, improving adherence at point-of-care.

Fused Deposition Modelling 3D printing and solubility improvement of BCS II and IV active ingredients - A narrative review

In the field of pharmaceutical research and development, Fused Deposition Modelling (FDM) 3D printing (3DP) has aroused growing interest within the last ten years. The use of thermoplastic polymers, combined with the melting process of the raw materials, offers the possibility of manufacturing amorphous solid dispersions (ASDs). In the pharmaceutical industry, the formulation of an ASD is a widely used strategy to improve the solubility of poorly soluble drugs (classified by the Biopharmaceutical Classification System (BCS) as class II and IV). In this review, an analysis of studies that have developed a FDM printed form containing a BCS class II or IV active substance was performed. The focus has been placed on the evaluation of the solid state of the active molecules (crystalline or amorphous) and on the study of their dissolution profile. Thus, the aim of this work is to highlight the interest of FDM 3DP to induce the amorphisation phenomenon of Class II and IV active substances by forming an ASD, and as result improving their solubility.

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.

Thermal degradation of Affinisol HPMC: Optimum Processing Temperatures for Hot Melt Extrusion and 3D Printing

PURPOSE

Affinisol HPMC HME is a new popular form of hypromellose specifically designed for the hot melt extrusion and 3D printing of pharmaceutical products. However, reports of its thermal stability include only data obtained under inert N2 atmosphere, which is not consistent with the common pharmaceutical practice. Therefore, detailed investigation of its real-life thermal stability in air is paramount for identification of potential risks and limitations during its high-temperature processing.

METHODS

In this work, the Affinisol HPMC HME 15LV powder as well as extruded filaments will be investigated by means of thermogravimetry, differential scanning calorimetry and infrared spectroscopy with respect to its thermal stability.

RESULTS

The decomposition in N2 was proceeded in accordance with the literature data and manufacturer's specifications: onset at ~260°C at 0.5°C·min-1, single-step mass loss of 90-95%. However, in laboratory or industrial practice, high-temperature processing is performed in the air, where oxidation-induced degradation drastically changes. The thermogravimetric mass loss in air proceeded in three stages: ~ 5% mass loss with onset at 150°C, ~ 70% mass loss at 200°C, and ~ 15% mass loss at 380°C. Diffusion of O2 into the Affinisol material was identified as the rate-determining step.

CONCLUSION

For extrusion temperatures ≥170°C, Affinisol exhibits a significant degree of degradation within the 5 min extruder retention time. Hot melt extrusion of pure Affinisol can be comfortably performed below this temperature. Utilization of plasticizers may be necessary for safe 3D printing.

Influence of fused deposition modelling printing parameters on tablet disintegration times: a design of experiments study

Despite the importance of process parameters in the printing of solid dosage forms using fused deposition modelling (FDM) technology, the field is still poorly explored. A design of experiment study was conducted to understand the complete set of process parameters of a custom developed FDM 3D printer and their influence on tablet disintegration time. Nine settings in the Simplify 3D printing process design software were evaluated with further experimental investigation conducted on the influence of infill percentage, infill pattern, nozzle diameter, and layer height. The percentage of infill was identified as the most impactful parameter, as increasing it parabolically affected the increase of disintegration time. Furthermore, a larger nozzle diameter prolonged tablet disintegration, since thicker extruded strands are generated through wider nozzles during the printing process. Three infill patterns were selected for in-depth analysis, demonstrating the clear importance of the geometry of the internal structure to resist mechanical stress during the disintegration test. Lastly, layer height did not influence the disintegration time. A statistical model with accurate fit (R 2 = 0.928) and predictability (Q 2 = 0.847) was created. In addition, only the infill pattern and layer height influenced both the uniformity of mass and uniformity of the disintegration time, which demonstrates the robustness of the printing process.

Development of an immediate release excipient composition for 3D printing via direct powder extrusion in a hospital

3D printing offers the possibility to prepare personalized tablets on demand, making it an intriguing technology for hospital pharmacies. For the implementation of 3D-printed tablets into the digital Closed Loop Medication Management system, the required tablet formulation and development of the manufacturing process as well as the pharmaceutical validation were conducted. The goal of the formulation development was to enable an optimal printing process and rapid dissolution of the printed tablets for the selected model drugs Levodopa/Carbidopa. The 3D printed tablets were prepared by direct powder extrusion. Printability, thermal properties, disintegration, dissolution, physical properties and storage stability were investigated by employing analytical methods such as HPLC-UV, DSC and TGA. The developed formulation shows a high dose accuracy and an immediate drug release for Levodopa. In addition, the tablets exhibit high crushing strength and very low friability. Unfortunately, Carbidopa did not tolerate the printing process. This is the first study to develop an immediate release excipient composition via direct powder extrusion in a hospital pharmacy setting. The developed process is suitable for the implementation in Closed-Loop Medication Management systems in hospital pharmacies and could therefore contribute to medication safety.

3D printing tablets for high-precision dose titration of caffeine

Through 3D printing (3DP), many parameters of solid oral dosage forms can be customised, allowing for truly personalised medicine in a way that traditional pharmaceutical manufacturing would struggle to achieve. One of the many options for customisation involves dose titration, allowing for gradual weaning of a medication at dose intervals smaller than what is available commercially. In this study we demonstrate the high accuracy and precision of 3DP dose titration of caffeine, selected due to its global prevalence as a behavioural drug and well-known titration-dependent adverse reactions in humans. This was achieved using a simple filament base of polyvinyl alcohol, glycerol, and starch, utilising hot melt extrusion coupled with fused deposition modelling 3DP. Tablets containing 25 mg, 50 mg, and 100 mg doses of caffeine were successfully printed with drug content in the accepted range prescribed for conventional tablets (90 - 110%), and excellent precision whereby the weights of all doses showed a relative standard deviation of no more than 3%. Importantly, these results proved 3D printed tablets to be far superior to splitting a commercially available caffeine tablet. Additional assessment of filament and tablet samples were reviewed by differential scanning calorimetry, thermogravimetric analysis, HPLC, and scanning electron microscopy, showing no evidence of degradation of caffeine or the raw materials, with smooth and consistent filament extrusion. Upon dissolution, all tablets achieved greater than 70% release between 50 and 60 min, showing a predictable rapid release profile regardless of dose. The outcomes of this study highlight the benefits that dose titration with 3DP can offer, especially to more commonly prescribed medications that can have even more harmful withdrawal-induced adverse reactions.

Recent patent-based review on the role of three-dimensional printing technology in pharmaceutical and biomedical applications

Three-dimensional printing (3DP) is emerging as an innovative manufacturing technology for biomedical and pharmaceutical applications, since the US FDA approval of Spritam as a 3D-printed drug. In the present review, we have highlighted the potential benefits of 3DP technology in healthcare, such as the ability to create patient-specific medical devices and implants, as well as the possibility of on-demand production of drugs and personalized dosage forms. We have further discussed future research to optimize 3DP processes and materials for pharmaceutical and biomedical applications. Cohesively, we have put forward the current state of active patents and applications related to 3DP technology in the healthcare and pharmaceutical industries including hearing aids, prostheses, medical devices and drug-delivery systems.

Development of 3D printed mini-waffle shapes containing hydrocortisone for children's personalized medicine

Hydrocortisone is mainly used in the substitution treatment of adrenal insufficiency which results in a dysregulation of cortisol. Compounding of hydrocortisone capsules remains the only low-dose oral treatment suitable for the pediatric population. However, capsules often show non-compliance in mass and content uniformity. Three-dimensional printing offers the prospect of practising personalized medicine for vulnerable patients like children. The goal of this work is to develop low-dose solid oral forms containing hydrocortisone by hot-melt extrusion coupled with fused deposition modeling for the pediatric population. Formulation, design and processes temperatures were optimized to produce printed forms with the desired characteristics. Red mini-waffle shapes containing drug loads of 2, 5 and 8 mg were successfully printed. This new 3D design allow to release more than 80% of the drug in 45 minutes indicating a conventional release like the one obtained with capsules. Mass and content uniformity, hardness and friability tests complied with European Pharmacopeia specifications, despite the considerable challenge of the small dimensions of the forms. This study demonstrates that FDM can be used to produce innovative pediatric-friendly printed shapes of an advanced pharmaceutical quality to practice personalize medicine.

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.

Corroborating various material-sparing techniques with hot melt extrusion for the preparation of triclabendazole amorphous solid dispersions

Amorphous solid dispersions (ASD) are one of the most adopted technologies for improving the solubility of novel molecules. Formulation of ASDs using solvent free methods such as hot melt extrusion (HME) has been in the spotlight off-lately. However, early-stage formulation development is tricky and a difficult bridge to pass due to limited drug availability. Material-sparing techniques (theoretical & practical) have been used for selecting suitable polymeric carriers for formulating ASDs. However, these techniques have limitations in predicting the effect of process parameters. The objective of this study is to use both theoretical and practical material-sparing techniques to optimize a polymer for the developing Triclabendazole (TBZ) ASDs. Initial screening by theoretical approaches suggested that TBZ is highly miscible with Kollidon®VA64 (VA64) and poorly miscible with Parteck®MXP (PVA). However, results from ASDs prepared using SCFe were opposite to these predictions. ASDs prepared using either technique and both VA64 and PVA showed >200x increase in solubility. Each formulation released >85% of drug in less than 15 mins. Although the thermodynamic phase diagram suggested that VA64 was the ideal polymer for TBZ-ASDs, it has certain limitations in factoring the different elements during melt-processing and hence, practical approaches like SCFe could help in predicting the drug-polymer miscibility for HME processing.

Influence of formulation variables on the processability and properties of tablets manufactured by fused deposition modelling

The present work studied the influence of different formulation variables (defined also as factors), namely, different polymers (HPC EF, PVA and HPMC-AS LG), drugs with different water solubilities (paracetamol, hydrochlorothiazide and celecoxib) and drug loads (10 or 30 %) on their processability by HME and FDM. Both filaments and tablets were characterized for physic and chemical properties (DSC, XRPD, FTIR) and performance properties (drug content, in vitro drug release). Experiments were designed to highlight relationships between the 3 factors selected and the mechanical properties of filaments, tablet mass and dissolution profiles of the model drugs from printed tablets. While the combination of hydrochlorothiazide and HPMC-AS LG could not be extruded, the combination of paracetamol with HPC EF turned the filaments too ductile and not stiff enough hampering the process of printing. All other polymer and drug combinations could be successfully extruded and printed. Models reflected the influence of the solubility of the drug considered but not the drug load in formulations. The ranking of the drug release rates was in good agreement with their solubilities. Furthermore, PVA presenting the fastest swelling rate, promoted the fastest drugs' releases in comparison with the other polymers studied. Overall, the study enabled the identification of the key factors affecting the properties of printed tablets, with the proposal of a model that has valued the relative contribution of each factor to the overall performance of tablets.

Pulmonary delivery of spray-dried Nisin ZP antimicrobial peptide for non-small cell lung cancer (NSCLC) treatment

Nisin ZP is an antimicrobial peptide (AMP) produced by the bacterium Lactococcus lactis, and we have previously demonstrated anticancer activity in NSCLC (A549) cells. In this study, we formulated a nisin ZP dry powder (NZSD) using a spray dryer to facilitate inhaled delivery for the treatment of NSCLC. Nisin ZP was spray-dried with mannitol, l-leucine, and trehalose in a ratio of 75:15:10 using Büchi mini spray-dryer B-290 in different drug loadings (10, 20, and 30% w/w). NZSD powder revealed a good powder yield of >55% w/w with ≤3 % w/w moisture content and high nisin ZP drug loading for all the peptide ratios. The NZSD powder particles were irregularly shaped with corrugated morphology. The presence of an endothermic peak in DSC thermograms and attenuated crystalline peaks in PXRD diffractograms confirmed the semi-crystalline powder nature of NZSD. The anticancer activity of nisin ZP was maintained after fabricating it into NZSD powder and showed a similar inhibitory concentration to free nisin ZP. Stability studies indicated that NZSD powders were stable for three months at 4 and 25 ℃ with more than 90% drug content and semi-crystalline nature, as confirmed by DSC and PXRD. Aerosolization studies performed using NGI indicated an aerodynamic diameter (MMAD) within the desired range (1-5 µm) and a high fine particle fraction (FPF > 75%) for all peptide ratios, suggesting powder deposition in the lung's respiratory airways. In conclusion, a dry powder of nisin ZP was formulated using a spray dryer with enhanced storage stability and suitable for inhaled delivery.

Improving drug release rate, drug-polymer miscibility, printability and processability of FDM 3D-printed tablets by weak acid-base interaction

Slow drug release, low drug-polymer miscibility, poor printability of polymers used, and high processing temperature are major challenges in developing FDM 3D-printed tablets. These challenges were addressed in this investigation by having a model basic drug, haloperidol (mp: 151.5 °C), interact with a weak acid, malic acid (mp: 130 °C), during the melt extrusion of formulations into filaments used for 3D-printing. Malic acid was selected as it was previously reported that it did not form any crystalline salt with haloperidol but its addition to aqueous media could greatly increase the solubility of haloperidol from ∼ 1 µg/mL to > 1 g per mL of water by acid-base supersolubilization. Concentrated solutions of haloperidol-malic acid mixtures produced amorphous materials upon drying. It has been observed in the present investigation that similar interaction between haloperidol and malic acid may also occur in the absence of water. Upon heating, haloperidol-malic acid mixtures at 1:1 and 1:2 molar ratios turned amorphous starting at ∼ 50 °C, which is much below the melting point of either component. When Kollidon® VA64, a brittle and non-printable polymer, was used as the polymeric carrier, the acid-base interaction greatly reduced the melt viscosity of haloperidol-malic acid-Kollidon® VA64 ternary mixtures. Consequently, melt extrusion of filaments and printing of tablets using such mixtures could be performed at much lower temperatures than those with haloperidol-Kollidon® VA64 binary mixtures. The filaments containing 15 % and 30 % haloperidol along with malic acid and Kollidon® VA64 could be printed into tablets at relatively low temperatures of 125 and 100 °C, respectively, thus making Kollidon® VA64 not only printable but also doing so at low temperatures. Up to 50 % w/w drug load in filaments was achieved without any crystallization of haloperidol or malic acid. Drug release at pH 2 and 6.8 from printed tablets with 100 % infill was 80 % in < 30 min. Thus, the acid-base interaction can successfully resolve multiple development challenges encountered with FDM 3D-printed tablets.

Investigation on the use of fused deposition modeling for the production of IR dosage forms containing Timapiprant

The present work focused on evaluating the feasibility of fused deposition modeling (FDM) in the development of a dosage form containing Timapiprant (TMP), also known as CHF6532, which is a novel active molecule indicated in the potential treatment of eosinophilic asthma upon oral administration. The resulting product could be an alternative, with potential towards personalization, of immediate release (IR) tablets used in the clinical studies. Formulations based on different polymeric carriers were screened, leading to the identification of a polyvinyl alcohol-based one, which turned out acceptable for versatility in terms of active ingredient content, printability and dissolution performance (i.e. capability to meet the dissolution specification set, envisaging >80% of the drug dissolved within 30 min). Following an in-depth evaluation on the influence of TMP solid state and of the voids volume resulting from printing on dissolution, few prototypes with shapes especially devised for therapy customization were successfully printed and were compliant with the dissolution specification set.

Processability of mesoporous materials in fused deposition modeling for drug delivery of a model thermolabile drug

The incorporation of drug-loaded mesoporous materials in dosage forms prepared with fused deposition modeling (FDM) has shown the potential to solve challenges relating to additive manufacturing techniques, such as the stability of poorly-soluble drugs in the amorphous state. However, the addition of these non-melting mesoporous materials significantly affects the mechanical properties of the filament used in FDM, which in turn affects the printability of the feedstock material. Therefore, in this study a full-factorial experimental design was utilized to investigate different processing parameters of the hot melt extrusion process, their effect on various mechanical properties and the potential correlation with the filaments' printability. The thermolabile, poorly-soluble drug ibuprofen was utilized as a model drug to assess the potential of two mesoporous materials, Mesoporous Magnesium Carbonate (MMC) and a silica-based material (MCM-41), to thermally protect the loaded drug. Factorial and principal components analysis displayed a correlation between non-printable MCM-41 filaments and their mechanical properties where printable filaments had a maximum stress >7.5 MPa and a Young's modulus >83 MPa. For MMC samples there was no clear correlation, which was in large part attributed to the filaments' inconsistencies and imperfections. Finally, both mesoporous materials displayed a thermal protective feature, as the decomposition due to the thermal degradation of a significant portion of the thermolabile drug was shifted to higher temperatures post-loading. This highlights the potential capability of such a system to be implemented for thermosensitive drugs in FDM applications.

Hot-Melt Extrusion-Based Fused Deposition Modeling 3D Printing of Atorvastatin Calcium Tablets: Impact of Shape and Infill Density on Printability and Performance

The main objective of the current research was to investigate the effect of tablet shapes (heart-shaped and round tablets) and infill densities (50% and 100%) on the drug release profiles of 3D printed tablets prepared by hot-melt extrusion paired with fused deposition modeling techniques. Drug-loaded filaments of 1.5 mm and 2.5 mm diameters were extruded using a Process 11 mm hot-melt extruder employing atorvastatin calcium as a model drug and Kollicoat® IR, Kollidon® VA64, Kollidon® 12PF, and Kolliphor® P407 as hydrophilic polymers. Filaments of Kollicoat® IR in combination with Kollidon® VA64/Kollidon® 12PF has resulted in successful printing of immediate release tablets. The mechanical properties of drug-loaded filaments were evaluated using a 3-point bend test and stiffness test. The transformation of a crystalline drug to an amorphous form and the absence of drug-polymer interactions were confirmed by differential scanning calorimetry and Fourier transform infrared spectroscopy, respectively. The effect of infill density on drug release profiles was greater than that of tablet shape. The stability of 3D printed tablets was preserved even after storage under accelerated conditions (40 ± 2°C and 75 ± 5% RH) for 6 months. Thus, the 3D printing process of hot-melt extrusion paired with fused deposition modeling serves as an alternative manufacturing approach for developing patient-focused doses.

3D printing of pharmaceuticals: approach from bench scale to commercial development

Background

The three-dimensional (3D) printing is paradigm shift in the healthcare sector. 3D printing is platform technologies in which complex products are developed with less number of additives. The easy development process gives edge over the conventional methods. Every individual needs specific dose treatment. 'One size fits all' is the current traditional approach that can shift to more individual specific in 3D printing. The present review aims to cover different perspectives regarding selection of drug, polymer and technological aspects for 3D printing. With respect to clinical practice, regulatory issue and industrial potential are also discussed in this paper.

Main body

The individualization of medicines with patient centric dosage form will become reality in upcoming future. It provides individual's need of dose by considering genetic profile, physiology and diseased condition. The tailormade dosages with unique drug loading and release profile of different geometrical shapes and sizes can easily deliver therapeutic dose. The technology can fulfill growing demand of efficiency in the dose accuracy for the patient oriented sectors like pediatric, geriatric and also easy to comply with cGMP requirements of regulated market. The clinical practice can focus on prescribing each individual's necessity of dose.

Conclusion

In the year 2015, FDA approved first 3D printed drug product, which is initiator in the new phase of manufacturing of pharmaceuticals. The tailormade formulations can be made in future for personalized medications. Regulatory approval from agencies can bring the 3DP product into the market. In the future, formulators can bring different sector-specific products for personalized need through 3DP pharmaceutical product.

Graphical Abstract

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

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

Dose Titration of Solid Dosage Forms via FDM 3D-Printed Mini-Tablets

The robustness of 3D-printed mini-tablets as a platform to administer milligram dosages, intended for age-specific therapy, without the need of tablet splitting while maintaining similar release profiles, was investigated. Griseofulvin, as a model poorly water-soluble drug, and hydroxypropyl cellulose along with Kollicoat Protect as polymers were used to prepare filaments at 1-20% drug concentrations via hot-melt extrusion (HME). Higher drug concentrations served for testing the feasibility of a reduced number of mini-tablets to be administered. A reliable dose titration in the range 0.19-3.91 mg at a high accuracy (R2 of 0.999) was achieved through composite unit (multi-unit) mini-tablets. All mini-tablets produced had excellent content uniformity and their label claim values were within the acceptable range, proving that HME processing followed by 3D printing promotes content uniformity even for mini-tablets containing low drug doses (0.19 mg). Remarkably, the proposed approach allowed achieving similar drug release profiles via composite unit mini-tablets as well as single mini-tablets at high drug concentrations. In contrast, split tablets demonstrated different release behaviors, attributed to their size and shape differences. Overall, the distinct advantages of mini-tablets to provide dose flexibility while maintaining similar release profiles was demonstrated.

Porous biomaterials for tissue engineering: a review

The field of biomaterials has grown rapidly over the past decades. Within this field, porous biomaterials have played a remarkable role in: (i) enabling the manufacture of complex three-dimensional structures; (ii) recreating mechanical properties close to those of the host tissues; (iii) facilitating interconnected structures for the transport of macromolecules and cells; and (iv) behaving as biocompatible inserts, tailored to either interact or not with the host body. This review outlines a brief history of the development of biomaterials, before discussing current materials proposed for use as porous biomaterials and exploring the state-of-the-art in their manufacture. The wide clinical applications of these materials are extensively discussed, drawing on specific examples of how the porous features of such biomaterials impact their behaviours, as well as the advantages and challenges faced, for each class of the materials.

Tunable Drug Release from Fused Deposition Modelling (FDM) 3D-Printed Tablets Fabricated Using a Novel Extrudable Polymer

Three-dimensional (3D) printing is proving to be a pivotal technology for developing personalized dosage forms with bench to bedside feasibility. Fused deposition modelling (FDM) 3D printing has emerged as the most used technique wherein molten drug-loaded polymer filaments are deposited layer-by-layer to fabricate a predefined shape and internal geometry. However, for precise FDM 3D printing, it is imperative for the filaments to have peculiar mechanical/physicochemical properties, which the majority of the FDA/GRAS approved polymers lack. In the current study, a novel water-soluble polymer, Poly(2-ethyl-tetra-oxazoline) [PETOx] has been investigated as an extrudable and printable polymer with two different types of drug molecule—dextromethorphan hydrobromide (DXM) and hydrochlorothiazide (HCTZ). Hot-stage microscopy experiments of drug:polymer (1:1 w/w) and filaments were carried out at 25−275 °C. HCTZ-loaded filament showed higher toughness of 17 ± 3.25 × 106 J/m3 compared with DXM and drug-free filament. Moisture sorption and flexural analysis was performed to understand the correlation of mechanical properties and storage humidity to printability. Varying the number of outer perimeters of each layer (shell number) was observed to affect the drug release pattern from the printlets. The DXM one-shell printlet showed >80%, whereas the DXM five-shell printlet showed >60% of the drug release within 60 min. PETOx could prove to be a high-performance and versatile 3D printable polymer.

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.

Fused deposition modeling 3D printing of solid oral dosage forms containing amorphous solid dispersions: How to elucidate drug dissolution mechanisms through surface spectral analysis techniques?

Many active principles belong to the second class of the Biopharmaceutics Classification System due to their low aqueous solubility. Elaboration of new solid oral forms by hot-melt extrusion and fused deposition modeling appears as a promising tool to increase the dissolution rate of these drugs. Indeed, hot-melt extrusion allows the amorphisation of drugs and forms with complex geometries are built by 3D printing. Therefore, the goal of this work is to enhance the dissolution rate of poorly soluble drugs using hot-melt extrusion coupled with fused deposition modeling. Four formulations containing Affinisol® 15LV, Kollidon® VA64 and a challenging amount of itraconazole (25% (wt.)) were successfully printed into forms of 20, 50 and 80% infill densities. Differential scanning calorimetry analysis has shown that itraconazole remained amorphous during 52 weeks. The drug release rate was highly improved compared to itraconazole in a crystalline form. The dissolution rate was influenced by the infill density and the polymer composition of printed forms which could modify respectively the surface to volume ratio and the distribution of the components in the printed forms. One formulation printed with 20% infill density even had a solubility profile similar to that of Sporanox®, the commercialized drug product in Belgium.

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

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

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

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

Filament-based 3D-printing of placebo dosage forms using brittle lipid-based excipients

In order to expand the limited portfolio of available polymer-based excipients for fabricating three-dimensional (3D) printed pharmaceutical products, Lipid-based excipients (LBEs) have yet to be thoroughly investigated. The technical obstacle of LBEs application is, however their crystalline nature that renders them very brittle and challenging for processing via 3D-printing. In this work, we evaluated the functionality of LBEs for filament-based 3D-printing of oral dosage forms. Polyglycerol partial ester of palmitic acid and polyethylene glycols monostearate were selected as LBEs, based on their chemical structure, possessing polar groups for providing hydrogen-bonding sites. A fundamental understanding of structure-function relationship was built to screen the critical material attributes relevant for both extrusion and 3D-printing processes. The thermal behavior of lipids, including the degree of their supercooling, was the critical attribute for their processing. The extrudability of materials was improved through different feeding approaches, including the common powder feeding and a devised liquid feeding setup. Liquid feeding was found to be more efficient, allowing the production of filaments with high flexibility and improved printability. Filaments with superior performance were produced using polyglycerol ester of palmitic acid. In-house designed modifications of the utilized 3D-printer were essential for a flawless processing of the filaments.

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

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

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.

The Role of 3D Printing Technology in Microengineering of Microneedles

Microneedles (MNs) are minimally invasive devices, which have gained extensive interest over the past decades in various fields including drug delivery, disease diagnosis, monitoring, and cosmetics. MN geometry and shape are key parameters that dictate performance and therapeutic efficacy, however, traditional fabrication methods, such as molding, may not be able to offer rapid design modifications. In this regard, the fabrication of MNs using 3D printing technology enables the rapid creation of complex MN prototypes with high accuracy and offers customizable MN devices with a desired shape and dimension. Moreover, 3D printing shows great potential in producing advanced transdermal drug delivery systems and medical devices by integrating MNs with a variety of technologies. This review aims to demonstrate the advantages of exploiting 3D printing technology as a new tool to microengineer MNs. Various 3D printing methods are introduced, and representative MNs manufactured by such approaches are highlighted in detail. The development of advanced MN devices is also included. Finally, clinical translation and future perspectives for the development of MNs using 3D printing are discussed.

Additive Manufacturing Strategies for Personalized Drug Delivery Systems and Medical Devices: Fused Filament Fabrication and Semi Solid Extrusion

Novel additive manufacturing (AM) techniques and particularly 3D printing (3DP) have achieved a decade of success in pharmaceutical and biomedical fields. Highly innovative personalized therapeutical solutions may be designed and manufactured through a layer-by-layer approach starting from a digital model realized according to the needs of a specific patient or a patient group. The combination of patient-tailored drug dose, dosage, or diagnostic form (shape and size) and drug release adjustment has the potential to ensure the optimal patient therapy. Among the different 3D printing techniques, extrusion-based technologies, such as fused filament fabrication (FFF) and semi solid extrusion (SSE), are the most investigated for their high versatility, precision, feasibility, and cheapness. This review provides an overview on different 3DP techniques to produce personalized drug delivery systems and medical devices, highlighting, for each method, the critical printing process parameters, the main starting materials, as well as advantages and limitations. Furthermore, the recent developments of fused filament fabrication and semi solid extrusion 3DP are discussed. In this regard, the current state of the art, based on a detailed literature survey of the different 3D products printed via extrusion-based techniques, envisioning future directions in the clinical applications and diffusion of such systems, is summarized.

Solid Dispersion Formulations by FDM 3D Printing-A Review

Additive manufacturing (AM) is revolutionizing the way medicines are designed, manufactured, and utilized. Perhaps, AM appears to be ideal for the fit-for-purpose manufacturing of medicines in contrast to the several disadvantages associated with the conventional fit-for-all mass production that accounts for less than 50% of pharmacotherapeutic treatment/management of diseases especially among children and elderly patients, as well as patients with special needs. In this review, we discuss the current trends in the application of additive manufacturing to prepare personalized dosage forms on-demand focusing the attention on the relevance of coupling solid dispersion with FDM 3D printing. Combining the two technologies could offer many advantages such as to improve the solubility, dissolution, and oral bioavailability of poorly soluble drugs in tandem with the concept of precision medicine and personalized dosing and to address the dilemma of commercial availability of FDM filaments loaded with Class II and/or Class IV drugs. However, thermal treatment especially for heat-sensitive drugs, regulatory, and ethical obligations in terms of quality control and quality assurance remain points of concern. Hence, a concerted effort is needed between the scientific community, the pharmaceutical industries, the regulatory agencies, the clinicians and clinical pharmacists, and the end-users to address these concerns.

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

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