Screening pharmaceutical excipient powders for use in commercial 3D binder jetting printers

Recent developments in 3D printing pharmaceutical, bioprinting and implant for tissue engineering formulations

This review article explores how 3D printing has the diversity in the drug development and the delivery of personalized medicine. The paradigm shift is from conventional methods to tailormade dosages and exploring the intricate interplay of drug selection, polymer compatibility alongwith technological advancements within the pharmaceutical arena. 3D printing is positioned as a crucial tool for catering to the specific requirements of patient-focused fields like pediatrics and geriatrics, ranging from addressing individual needs to improving dosage precision. By harnessing genetic profiles, physiological nuances, and disease conditions, this technology enables the creation of bespoke medications with unique drug loading and release profiles. In developing the newer implants the 3D printing has to be developed alongwith consideration of biological aspects as well as technical aspects. It has to be aligned with multifunctional aspects to cater one optimized product. Furthermore, this paper elucidates the regulatory considerations and industrial implications surrounding 3D printing in pharmaceuticals. Emphasizing compliance with current Good Manufacturing Practices (CGMP) and its potential for streamlined production in regulated markets, the paper underscores the transformative power of 3D printing in reshaping clinical practice and optimizing patient outcomes.

Current developments and advancements of 3-dimensional printing in personalized medication and drug screening

INTRODUCTION

3-Dimensional printing (3DP) is an additive manufacturing (AM) technique that is expanding quickly because of its low cost and excellent efficiency. The 3D printing industry grew by 19.5 % in 2021 in spite of the COVID-19 epidemic, and by 2026, the worldwide market is expected to be valued up to 37.2 billion US dollars.

CONTENT

Science Direct, Scopus, MEDLINE, EMBASE, PubMed, DOAJ, and other academic databases provide evidence of the increased interest in 3DP technology and innovative drug delivery approaches in recent times.

SUMMARY

In this review four main 3DP technologies that are appropriate for pharmaceutical applications: extrusion-based, powder-based, liquid-based, and sheet lamination-based systems are discussed. This study is focused on certain 3DP technologies that may be used to create dosage forms, pharmaceutical goods, and other items with broad regulatory acceptance and technological viability for use in commercial manufacturing. It also discusses pharmaceutical applications of 3DP in drug delivery and drug screening.

OUTLOOK

The pharmaceutical sector has seen the prospect of 3D printing in risk assessment, medical personalisation, and the manufacture of complicated dose formulas at a reasonable cost. AM has great promise to revolutionise the manufacturing and use of medicines, especially in the field of personalized medicine. The need to understand more about the potential applications of 3DP in medical and pharmacological contexts has grown over time.

Binder jetting 3D printing in fabricating pharmaceutical solid products for precision medicine

Current treatment strategies are moving towards patient-centricity, which emphasizes the need for new solutions allowing for medication tailored to a patient. This can be realized by precision medicine where patient diversity is considered during treatment. However, the broader use of precision medicine is restricted by the current technological solutions and rigid manufacturing of pharmaceutical products by mass production principles. Additive manufacturing of pharmaceutical products can provide a feasible solution to this challenge. In this review, a particular subtype of additive manufacturing, that is, binder jetting 3D printing, is introduced as a solution for fabricating pharmaceutical solid products that can be considered as precision medicine. Technical aspects, practical applications, unique advantages and challenges related to this technique are discussed, indicating that binder jetting 3D printing possesses the potential for fabricating already new product prototypes, where diversity in patient treatment in terms of the needs for specific drug type, dose and drug release can be accounted. To further advance this type of mass customization of pharmaceuticals, multidisciplinary research initiatives are needed not only to cover the engineering aspects but also to bridge these innovations with patient-centric perspectives.

Co-processed materials testing as excipients to produce Orally Disintegrating Tablets (ODT) using binder jet 3D-printing technology

The use of co-processed materials for Orally Disintegrating Tablets (ODT) preparation by direct compression is well consolidated. However, the evaluation of their potential for ODT preparation by 3D printing technology remains almost unexplored. The present study aimed to estimate the use of commercially available co-processed excipients, conventionally applied in compression protocols, for the preparation of ODTs with binder jetting-3D printing technology. The latter was selected among the 3D printing techniques because the deposition of multiple powder layers allows for obtaining highly porous and easily disintegrating dosage forms. The influence of some process parameters, including layer thickness, type of waveform and spread speed, on the physical and mechanical properties of the prototypes printed were evaluated. Our results suggested that binder jetting-3D printing technology could benefit from the co-processed excipients for the preparation of solid dosage forms. The process optimization conducted with the experiments reported in this work indicated that additional excipients were needed to improve the physical properties of the resulting ODTs.

Surface Engineering Methods for Powder Bed Printed Tablets to Optimize External Smoothness and Facilitate the Application of Different Coatings

In a previous attempt to achieve ileo-colonic targeting of bovine intestinal alkaline phosphatase (BIAP), we applied a pH-dependent coating, the ColoPulse coating, directly on powder bed printed (PBP) tablets. However, the high surface roughness necessitated an additional sub-coating layer [Nguyen, K. T. T., Pharmaceutics 2022]. In this study, we aimed to find a production method for PBP tablets containing BIAP that allows the direct application of coating systems. Alterations of the printing parameters, binder content, and printing layer height, when combined, were demonstrated to create visually less rough PBP tablets. The addition of ethanol vapor treatment further improved the surface's smoothness significantly. These changes enabled the direct application of the ColoPulse, or enteric coating, without a sub-coating. In vitro release testing showed the desired ileo-colonic release or upper-intestinal release for ColoPulse or enteric-coated tablets, respectively. Tablets containing BIAP, encapsulated within an inulin glass, maintained a high enzymatic activity (over 95%) even after 2 months of storage at 2-8 °C. Importantly, the coating process did not affect the activity of BIAP. In this study, we demonstrate, for the first time, the successful production of PBP tablets with surfaces that are directly coatable with the ColoPulse coating while preserving the stability of the encapsulated biopharmaceutical, BIAP.

3D printing of amorphous solid dispersions: A comparison of fused deposition modeling and drop-on-powder printing

Nowadays, a high number of pipeline drugs are poorly soluble and require solubility enhancement by e.g., manufacturing of amorphous solid dispersion. Pharmaceutical 3D printing has great potential in producing amorphous solid oral dosage forms. However, 3D printing techniques differ greatly in terms of processing as well as tablet properties. In this study, an amorphous formulation, which had been printed via Fused Deposition Modeling and drop-on-powder printing, also known as binder jetting, was characterized in terms of solid-state properties and physical stability. Solid state assessment was performed by differential scanning calorimetry, powder X-ray diffraction and polarized microscopy. The supersaturation performance of the amorphous solid dispersion was assessed via non-sink dissolution. We further evaluated both 3D printing techniques regarding their processability as well as tablet uniformity in terms of dimension, mass and content. Challenges and limitations of each 3D printing technique were discussed. Both techniques are feasible for the production of amorphous formulations. Results indicated that Fused Deposition Modeling is better suited for production, as the recrystallization tendency was lower. Still, filament production and printing presented a major challenge. Drop-on-powder printing can be a viable alternative for the production of amorphous tablets, when a formulation is not printable by Fused Deposition Modeling.

Coating of Primary Powder Particles Improves the Quality of Binder Jetting 3D Printed Oral Solid Products

Binder jetting (BJ) 3D printing is especially suitable for the fabrication of an orodispersible solid dosage form, as it is an efficient way to avoid the use of mechanical forces typical for compaction-based processes. However, one of the existing challenges related to pharmaceutical applications of BJ is the relatively high amount of binder needed in the primary powder to ensure the sufficient mechanical strength of printed products. In this study, a strategy based on pre-processing with a thin layer coating was explored. With this strategy, the matrix particles (lactose monohydrate) of the primary powder for BJ 3D printing were coated with the binder (polyvinylpyrrolidone, PVP). The investigated compositions of the primary powder contained PVP at three levels, namely, 10 %, 15% and 20% (w/w). The primary powder compositions were prepared with or without the coated lactose powder, and they were subsequently 3D BJ printed into oral solid products with paracetamol as a model active drug substance. The presence of coated lactose in the primary powder increased the interparticulate interactions in the BJ 3D printed products. Especially for the composition with a relatively small amount of binder (i.e., 10% and 15% w/w PVP in the primary powder), the use of coated particles significantly improved the resistance to crushing and decreased the disintegration time of printed products. In conclusion, thin layer coating is an effective way to pre-process primary powder particles for BJ 3D printing of oral solid products.

Drop-on-powder 3D printing of amorphous high dose oral dosage forms: Process development, opportunities and printing limitations

Drop-on-powder 3D printing is able to produce highly drug loaded solid oral dosage forms. However, this technique is mainly limited to well soluble drugs. The majority of pipeline compounds is poorly soluble, though, and requires solubility enhancement, e.g., via formation of amorphous solid dispersions. This study presents a detailed and systematic development approach for the production of tablets containing high amounts of a poorly soluble, amorphized drug via drop-on-powder 3D printing (also known as binder jetting). Amorphization of the compound was achieved via hot-melt extrusion using the exemplary system of the model compound ketoconazole and copovidone as matrix polymer at drug loadings of 20% and 40%. The milled extrudate was used as powder for printing and the influence of inks and different ink-to-powder ratios on recrystallization of ketoconazole was investigated in a material-saving small-scale screening. Crystallinity assessment was performed using differential scanning calorimetry and polarized light microscopy to identify even small traces of crystallinity. Printing of tablets showed that the performed small-scale screening was capable to identify printing parameters for the development of amorphous and mechanically stable tablets via drop-on-powder printing. A stability study demonstrated physically stable tablets over twelve weeks at accelerated storage conditions.

The Application and Challenge of Binder Jet 3D Printing Technology in Pharmaceutical Manufacturing

Three-dimensional (3D) printing is an additive manufacturing technique that creates objects under computer control. Owing to the rapid advancement of science and technology, 3D printing technology has been widely utilized in processing and manufacturing but rarely used in the pharmaceutical field. The first commercial form of Spritam® immediate-release tablet was approved by FDA in 2015, which promoted the advancement of 3D printing technology in pharmaceutical development. Three-dimensional printing technology is able to meet individual treatment demands with customized size, shape, and release rate, which overcomes the difficulties of traditional pharmaceutical technology. This paper intends to discuss the critical process parameters of binder jet 3D printing technology, list its application in pharmaceutical manufacturing in recent years, summarize the still-open questions, and demonstrate its great potential in the pharmaceutical industry.

Novel 3D Printed Modular Tablets Containing Multiple Anti-Viral Drugs: a Case of High Precision Drop-on-Demand Drug Deposition

3D printed drug delivery systems have gained tremendous attention in pharmaceutical research due to their inherent benefits over conventional systems, such as provisions for customized design and personalized dosing. The present study demonstrates a novel approach of drop-on-demand (DoD) droplet deposition to dispense drug solutions precisely on binder jetting-based 3D printed multi-compartment tablets containing 3 model anti-viral drugs (hydroxychloroquine sulfate - HCS, ritonavir and favipiravir). The printing pressure affected the printing quality whereas the printing speed and infill density significantly impacted the volume dispersed on the tablets. Additionally, the DoD parameters such as nozzle valve open time and cycle time affected both dispersing volume and the uniformity of the tablets. The solid-state characterization, including DSC, XRD, and PLM, revealed that all drugs remained in their crystalline forms. Advanced surface analysis conducted by microCT imaging as well as Artificial Intelligence (AI)/Deep Learning (DL) model validation showed a homogenous drug distribution in the printed tablets even at ultra-low doses. For a four-hour in vitro drug release study, the drug loaded in the outer layer was released over 90%, and the drug incorporated in the middle layer was released over 70%. In contrast, drug encapsulated in the core was only released about 40%, indicating that outer and middle layers were suitable for immediate release while the core could be applied for delayed release. Overall, this study demonstrates a great potential for tailoring drug release rates from a customized modular dosage form and developing personalized drug delivery systems coupling different 3D printing techniques.

3D-Powder-Bed-Printed Pharmaceutical Drug Product Tablets for Use in Clinical Studies

Printing of phase 1 and 2a clinical trial formulations represents an interesting industrial application of powder bed printing. Formulations for clinical trials are challenging because they should enable flexible changes in the strength of the dosage form by varying the active pharmaceutical ingredient (API) percentage and tablet mass. The aim of this study was to investigate how powder bed 3D printing can be used for development of flexible platforms for clinical trials, suitable for both hydrophilic and hydrophobic APIs, using only conventional tableting excipients. A series of pre-formulation and formulation studies were performed to develop two platform formulations for clinical trials using acetaminophen and diclofenac sodium as model compounds and lactose and starch as excipients. The results showed that the type of starch used as the formulation binder must be optimized based on the type of API. Moreover, powder blend flow and liquid penetration ability proved to be critical material attributes (CMAs) that need to be controlled, particularly at high drug loading. Optimization of these CMAs was performed by selecting the appropriate particle size of the API or by addition of silica. A critical process parameter that had to be controlled for production of tablets of good quality was the quantity of the printing ink. After optimization of both the formulation and process parameters, two platform formulations, that is, one for each API, were successfully developed. Within each platform, drug loading from 5 up to 50% w/w and tablet mass from 50 to 500 mg were achieved. All 3D-printed tablets could be produced at tensile strength above 0.2 MPa, and most tablets could enable immediate release (i.e., >80% w/w within 30 min).

Structured approach for designing drug-loaded solid products by binder jetting 3D printing

Additive manufacturing allows for designing innovative properties to pharmaceutical products. Binder jetting (BJ) 3D printing is one of the key techniques within innovative manufacturing. In this study, a structured approach according to the Quality by Design (QbD) principles was implemented to explore the factors affecting fabrication of drug-loaded products produced by BJ 3D printing. The investigated factors included the weight ratio of binder in primary powder and the process parameters related to printing (layer thickness and number of layers). Critical quality attributes, namely disintegration time, tensile strength, friability, dimensions (diameter and height accuracies), residual water content, weight and drug loading were determined based on the quality target product profile of a tablet analogue. The experimental results with a 2-level full factorial design were modeled by multiple linear regression. It was found that binder content was an important factor determining the integrity of the printed products, and the formation of the microstructure of the product was affected by multiple material properties and process parameters. QbD is a systematic and effective approach providing mechanistic understanding of BJ 3D printing and allowing for an efficient design of products with the desired quality.

Influence of the Binder Jetting Process Parameters and Binder Liquid Composition on the Relevant Attributes of 3D-Printed Tablets

Binder jetting has the potential to revolutionize the way we produce medicine. However, tablets produced by binder jetting technology can be quite fragile and hard to handle. In this study, the printing process and ink composition were examined to optimize the mechanical properties of tablets. A model formulation containing the ketoprofen drug was developed and used as a base for optimization. Firstly, important printing parameters were identified with a fractional factorial design. Saturation and layer height critically influenced selected tablet properties. Relevant process parameters were optimized for tablet mechanical strength by using the D-optimization DoE approach. The best mechanical properties were achieved when saturation was set to 1 and layer height to 150 µm. On the other hand, binder ink composition did not appear to impact tablet mechanical strength as much as process parameters did. Three ethanol-water mixtures were tested at three tablet strength levels and no definitive conclusions could be drawn. The binder jetting process can be wasteful, especially if the unbound powder cannot be reused. To determine the suitability of powder blend recycling, the ketoprofen content was measured for 27 subsequent batches of tablets. While the trendline did indicate a slight reduction in ketoprofen content, the powder blend reuse can nevertheless be employed.

Additive Manufacturing of Solid Products for Oral Drug Delivery Using Binder Jetting Three-Dimensional Printing

Binder jetting (BJ) three-dimensional (3D) printing is becoming an established additive manufacturing technology for manufacturing of solid products for oral drug delivery. Similar to traditional solutions based on compaction of powder mixture, successful processing of BJ products requires control of bulk powder properties. In contrast to traditional compaction-based process, BJ 3D printing allows for flexible modifications on microstructure, material composition and dose in the printed pharmaceutical products. Currently, systematic strategies for selecting excipients and optimizing the printing process have not been fully established. To address this challenge, a summary of the published work and selected patent literature around BJ 3D printing to fabricate pharmaceutical solid products for oral administration purposes is presented. First, an overview of characteristics of printed products as a part of the product design and a description of the commonly used excipients and active pharmaceutical ingredients is given. The critical powder and ink properties, as well as physical geometries and inner structures of a final product, are discussed in term of the mechanisms that determine the formation of a printed solid product and finally the quality of this product. This review is also summarizing the technical features of printers, printheads, and the critical considerations for post-processing procedures. BJ 3D printing is one of the most promising additive manufacturing technologies for mass customization of pharmaceutical products.

3D Printing: an appealing technology for the manufacturing of solid oral dosage forms

OBJECTIVES

The traditional manufacturing methods of solid oral dosage forms (SODFs) are reported to be time-consuming, highly expensive and not tailored to the patient's needs. Three-dimensional printing (3DP) is an innovative emerging technology that can help to overcome these issues. The aim of this review is to describe the most employed 3DP technologies, materials and the state of the art on 3DP SODFs. Characterization techniques of 3DP SODFs, challenges and regulatory issues are also discussed.

KEY FINDINGS

The interest in the investigation of the suitability of 3DP as an alternative strategy for the fabrication of SODFs is growing. Different 3DP technologies and starting materials have been investigated for the development of SODFs. Numerous SODFs with complex geometries and composition, and with different release patterns, have been successfully manufactured via 3DP. Despite that, just one 3DP SODF has reached the market.

SUMMARY

3DP can be a promising alternative to the classical SODFs manufacturing methods. However, numerous technically and regulatory challenges still need to be addressed in order 3DP to be extensively used in the pharmaceutical sector.