Selective laser sintering additive manufacturing of dosage forms: Effect of powder formulation and process parameters on the physical properties of printed tablets

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.

Cold Laser Sintering of Medicines: Toward Carbon Neutral Pharmaceutical Printing

Selective laser sintering (SLS) is an emerging three-dimensional (3D) printing technology that uses a laser to fuse powder particles together, which allows the fabrication of personalized solid dosage forms. It possesses great potential for commercial use. However, a major drawback of SLS is the need to heat the powder bed while printing; this leads to high energy consumption (and hence a large carbon footprint), which may hinder its translation to industry. In this study, the concept of cold laser sintering (CLS) is introduced. In CLS, the aim is to sinter particles without heating the powder bed, where the energy from the laser, alone, is sufficient to fuse adjacent particles. The study demonstrated that a laser power above 1.8 W was sufficient to sinter both KollicoatIR and Eudragit L100-55-based formulations at room temperature. The cold sintering printing process was found to reduce carbon emissions by 99% compared to a commercial SLS printer. The CLS printed formulations possessed characteristics comparable to those made with conventional SLS printing, including a porous microstructure, fast disintegration time, and molecular dispersion of the drug. It was also possible to achieve higher drug loadings than was possible with conventional SLS printing. Increasing the laser power from 1.8 to 3.0 W increased the flexural strength of the printed formulations from 0.6 to 1.6 MPa, concomitantly increasing the disintegration time from 5 to over 300 s. CLS appears to offer a new route to laser-sintered pharmaceuticals that minimizes impact on the environment and is fit for purpose in Industry 5.0.

Application of 3D printing on the design and development of pharmaceutical oral dosage forms

3D printing technologies confer an unparalleled degree of control over the material distribution on the structures they produce, which has led them to become an extremely attractive research topic in pharmaceutical dosage form development, especially for the design of personalized treatments. With fine tuning in material selection and careful design, these technologies allow to tailor not only the amount of drug administered but the biopharmaceutical behaviour of the dosage forms as well. While fused deposition modelling (FDM) is still the most studied 3D printing technology in this area, others are gaining more relevance, which has led to many new and exciting dosage forms developed during 2022 and 2023. Considering that these technologies, in time, will join the current manufacturing methods and with the ever-increasing knowledge on this topic, our review aims to explore the advantages and limitations of 3D printing technologies employed in the design and development of pharmaceutical oral dosage forms, giving special focus to the most important aspects governing the resulting drug release profiles.

3D printed dosage forms, where are we headed?

INTRODUCTION

3D Printing (3DP) is an innovative fabrication technology that has gained enormous popularity through its paradigm shifts in manufacturing in several disciplines, including healthcare. In this past decade, we have witnessed the impact of 3DP in drug product development. Almost 8 years after the first USFDA approval of the 3D printed tablet Levetiracetam (Spritam), the interest in 3DP for drug products is high. However, regulatory agencies have often questioned its large-scale industrial practicability, and 3DP drug approval/guidelines are yet to be streamlined.

AREAS COVERED

In this review, major technologies involved with the fabrication of drug products are introduced along with the prospects of upcoming technologies, including AI (Artificial Intelligence). We have touched upon regulatory updates and discussed the burning limitations, which require immediate focus, illuminating status, and future perspectives on the near future of 3DP in the pharmaceutical field.

EXPERT OPINION

3DP offers significant advantages in rapid prototyping for drug products, which could be beneficial for personalizing patient-based pharmaceutical dispensing. It seems inevitable that the coming decades will be marked by exponential growth in personalization, and 3DP could be a paradigm-shifting asset for pharmaceutical professionals.

3D printed dispersible efavirenz tablets: A strategy for nasogastric administration in children

Enteral feeding tubes (EFTs) can be placed in children diagnosed with HIV which need nutritional support due to malnutrition. EFTs are the main route for medication administration in these patients, bringing up concerns about off label use of medicines, dose inaccuracy and tube clogging. Here we report for the first time the use of selective laser sintering (SLS) 3D printing to develop efavirenz (EFZ) dispersible printlets for patients with HIV that require EFT administration. Water soluble polymers Parteck® MXP and Kollidon® VA64 were used to obtain both 500 mg (P500 and K500) and 1000 mg printlets (P1000 and K1000) containing 200 mg of EFZ each. The use of SLS 3D printing obtained porous dosage forms with high drug content (20 % and 40 % w/w) and drug amorphization using both polymers. P500, K500 and K1000 printlets reached disintegration in under 230 s in 20 mL of water (25 ± 1 °C), whilst P1000 only partially disintegrated, possibly due to saturation of the polymer in the medium. As a result, the development of dispersible EFZ printlets using hydrophilic polymers can be explored as a potential strategy for drug delivery through EFTs in paediatrics with HIV, paving the way towards the exploration of more rapidly disintegrating polymers and excipients for SLS 3D printing.

Powder bed fusion-laser beam (PBF-LB) three-dimensional (3D) printing: Influence of laser hatching distance on the properties of zolpidem tartrate tablets

Laser sintering, known as powder bed fusion-laser beam (PBF-LB), offers promising potential for the fabrication of patient-specific drugs. The aim of this study was to provide an insight into the PBF-LB process with regard to the process parameters, in particular the laser hatching distance, and its influence on the properties of zolpidem tartrate (ZT) tablets. PHARMACOAT® 603 was used as the polymer, while Candurin® Gold Sheen and AEROSIL® 200 were added to facilitate 3D printing. The particle size distribution of the powder blend showed that the layer height should be set to 100 µm, while the laser hatching distance was varied in five different steps (50, 100, 150, 200 and 250 µm), keeping the temperature and laser scanning speed constant. Increasing the laser hatching distance and decreasing the laser energy input led to a decrease in the colour intensity, mass, density and hardness of the ZT tablets, while the disintegration and dissolution rate were faster due to the more fragile bonds between the particles. The laser hatching distance also influenced the ZT dosage, indicating the importance of this process parameter in the production of presonalized drugs. The absence of drug-polymer interactions and the amorphization of the ZT were confirmed.

Additive Manufacturing: A Comprehensive Review

Additive manufacturing has revolutionized manufacturing across a spectrum of industries by enabling the production of complex geometries with unparalleled customization and reduced waste. Beginning as a rapid prototyping tool, additive manufacturing has matured into a comprehensive manufacturing solution, embracing a wide range of materials, such as polymers, metals, ceramics, and composites. This paper delves into the workflow of additive manufacturing, encompassing design, modeling, slicing, printing, and post-processing. Various additive manufacturing technologies are explored, including material extrusion, VAT polymerization, material jetting, binder jetting, selective laser sintering, selective laser melting, direct metal laser sintering, electron beam melting, multi-jet fusion, direct energy deposition, carbon fiber reinforced, laminated object manufacturing, and more, discussing their principles, advantages, disadvantages, material compatibilities, applications, and developing trends. Additionally, the future of additive manufacturing is projected, highlighting potential advancements in 3D bioprinting, 3D food printing, large-scale 3D printing, 4D printing, and AI-based additive manufacturing. This comprehensive survey aims to underscore the transformative impact of additive manufacturing on global manufacturing, emphasizing ongoing challenges and the promising horizon of innovations that could further elevate its role in the manufacturing revolution.

Sketching feasibility of additively manufactured different size gradient conventional hollow capsular shells (HCSs) by selective laser sintering (SLS): From design to applications

Additive manufacturing (AM) is widely used to fabricate 3D printed objects from Computer-aided Design (CAD) prepared using the SolidWorks CAD modelling software. Different printing techniques are used to fabricate desired 3D objects; among all these techniques, it is widely accepted that SLS is one of the most effective methods of 3D printing for fabricating drug-loaded solid oral dosage forms (SODFs) in bulk quantities using the single-step process. Different SODFs, such as pills, miniprintlets, dual miniprintlets, and tablets, were fabricated with different sizes and shapes. In this study, for the first time, we introduce SLS-mediated hollow capsular shells (HCSs) with the help of the SLS 3D printing technique. This work aimed to explore the sinterability and feasibility of sketching HCSs using the SLS-mediated sintering technique with different marketed sizes of capsules ranging from 000 to 5. Here, we have utilized Kolliphor P 188 (KP 188) and Kollidon SR (KSR) in a 1:1 ratio as a matrix-forming agent and 1% charcoal as a laser absorption-enhancing material. In accordance with the CAD models, we have fabricated the gradient conventional different sizes of HCSs ranging from 000 to 5 using the constant printing parameters and composition. Fabricated all biobased HCSs were subjected to the assessment of mechanistic and physicochemical parameters using varied analytical tools. In the current study, tartrazine dye is used to assess the release pattern from HCSs, which resulted in the modified release pattern. The adapted approach will be the futuristic approach to replace animal-based gelatin capsules with pharmaceutical-grade polymer-based HCSs with a modified release with optimum mechanical strength.

3D-printed dosage forms for oral administration: a review

Oral administration is the most commonly used form of treatment due to its advantages, including high patient compliance, convenient administration, and minimal preparation required. However, the traditional preparation process of oral solid preparation has many defects. Although continuous manufacturing line that combined all the unit operations has been developed and preliminarily applied in the pharmaceutical industry, most of the currently used manufacturing processes are still complicated and discontinuous. As a result, these complex production steps will lead to low production efficiency and high quality control risk of the final product. Additionally, the large-scale production mode is inappropriate for the personalized medicines, which commonly is customized with small amount. Several attractive techniques, such as hot-melt extrusion, fluidized bed pelletizing and spray drying, could effectively shorten the process flow, but still, they have inherent limitations that are challenging to address. As a novel manufacturing technique, 3D printing could greatly reduce or eliminate these disadvantages mentioned above, and could realize a desirable continuous production for small-scale personalized manufacturing. In recent years, due to the participation of 3D printing, the development of printed drugs has progressed by leaps and bounds, especially in the design of oral drug dosage forms. This review attempts to summarize the new development of 3D printing technology in oral preparation and also discusses their advantages and disadvantages as well as potential applications.

Visualizing disintegration of 3D printed tablets in humans using MRI and comparison with in vitro data

Three-dimensional (3D) printing is revolutionising the way that medicines are manufactured today, paving the way towards more personalised medicine. However, there is limited in vivo data on 3D printed dosage forms, and no studies to date have been performed investigating the intestinal behaviour of these drug products in humans, hindering the complete translation of 3D printed medications into clinical practice. Furthermore, it is unknown whether conventional in vitro release tests can accurately predict the in vivo performance of 3D printed formulations in humans. In this study, selective laser sintering (SLS) 3D printing technology has been used to produce two placebo torus-shaped tablets (printlets) using different laser scanning speeds. The printlets were administered to 6 human volunteers, and in vivo disintegration times were assessed using magnetic resonance imaging (MRI). In vitro disintegration tests were performed using a standard USP disintegration apparatus, as well as an alternative method based on the use of reduced media volume and minimal agitation. Printlets fabricated at a laser scanning speed of 90 mm/s exhibited an average in vitro disintegration time of 7.2 ± 1 min (measured using the USP apparatus) and 25.5 ± 4.1 min (measured using the alternative method). In contrast, printlets manufactured at a higher laser scanning speed of 130 mm/s had an in vitro disintegration time of 2.8 ± 0.8 min (USP apparatus) and 18.8 ± 1.9 min (alternative method). When tested in humans, printlets fabricated at a laser scanning speed of 90 mm/s showed an average disintegration time of 17.3 ± 7.2 min, while those manufactured at a laser scanning speed of 130 mm/s exhibited a shorter disintegration time of 12.7 ± 6.8 min. Although the disintegration times obtained using the alternative method more closely resembled those obtained in vivo, no clear correlation was observed between the in vitro and in vivo disintegration times, highlighting the need to develop better in vitro methodology for 3D printed drug products.

Impact of polymer chemistry on critical quality attributes of selective laser sintering 3D printed solid oral dosage forms

The aim of this study is to investigate the influence of polymer chemistry on the properties of oral dosage forms produced using selective laser sintering (SLS). The dosage forms were printed using different grades of polyvinyl alcohol or copovidone in combination with indomethacin as the active pharmaceutical ingredient. The properties of the printed structures were assessed according to European Pharmacopoeia guidelines at different printing temperatures and laser scanning speeds in order to determine the suitable printing parameters. The results of the study indicate that the chemical properties of the polymers, such as dynamic viscosity, degree of hydrolyzation, and molecular weight, have significant impact on drug release and kinetics. Drug release rate and supersaturation can be modulated by selecting the appropriate polymer type. Furthermore, the physical properties of the dosage forms printed under the same settings are influenced by the selected polymer type, which determines the ideal manufacturing settings. This study demonstrates how the chemical properties of the polymer can determine the appropriate choice of manufacturing settings and the final properties of oral dosage forms produced using SLS.

In situ thermal image analysis of selective laser sintering for oral dosage form manufacturing

Additive Manufacturing (AM) is a fast-growing approach to produce personalized oral dosage forms. Even though some AM technologies are promising as alternative to conventional compounding with resulting dosage manipulation, they still suffer from a lack of quality control. Due to the high regulatory demands and standards applied to dosage forms in the case of dose accuracy and tablet properties such as friability, effective quality control is a key feature in promoting AM as a valid technology for patient-tailored medications. One of the AM techniques used is selective laser sintering, which allows for capturing the surface state layer-by-layer during the printing process. It provides the opportunity to apply non-destructive quality control based on image analysis extracting essential data at each layer of the sintering process. This work is devoted to establishing the value of data gathered via thermal image analysis for the subsequent quality control.