A comprehensive overview of extended release oral dosage forms manufactured through hot melt extrusion and its combination with 3D printing

Hot-melt extruded-FDM 3D-printed polyethylene oxide tablets: Dissolution imaging analysis of swelling and drug release

Recent developments in pharmacogenetics have emphasised the importance of customised medication, driving interest in technologies like FDM 3D-printing for tailored drug delivery. FDM 3D-printing is a promising technique for the on-demand manufacturing of customised oral dosage forms, providing flexibility in terms of shape and size, dose and drug release profiles. This study investigates the fabrication and characterisation of 3D-printed oral dosage forms using PEO as the primary polymer and PEG 6 K as a plasticiser. Firstly, the printability of the PEO filaments with different propranolol hydrochloride concentrations was explored using the hot-melt extrusion technology. The influence of the propranolol hydrochloride concentrations on the mechanical properties of the filaments was examined was then examined after which surface characteristics, including roughness and wettability, were evaluated. Dissolution imaging was used to visualise the effects of drug content on the swelling and dissolution characteristics of the PEO-based 3D-printed tablets. Results showed a reduction in the flexural stress of the filaments with increasing drug load. It was also observed that increasing the drug load led to higher surface roughness and lower contact angles of the 3D-printed PEO tablets, implying increased surface hydrophilicity. The swelling behaviour of the tablets increased with higher drug concentrations, resulting in a larger gel layer formation. When comparing the drug release percentages, the release rate was higher in the 10 mg propranolol tablets, suggesting that a lower drug content led to a faster release. The greater gel layer of the 40 mg PPN tablets hindered the drug release by acting as a diffusion barrier, while the 10 mg PPN tablets, with less swelling and gel formation, experienced a faster drug release. These findings show the importance of drug content in modifying the surface properties, swelling behaviour, and drug release profiles of 3D-printed PEO tablets. The study also demonstrates the novel use of dissolution imaging for 3D-printed dosage forms, providing valuable quantitative and qualitative insights into swelling dynamics and channel formation to optimise 3D-printed tablets for drug delivery systems.

A review of precision medicine in developing pharmaceutical products: Perspectives and opportunities

Over the next decade, Precision Medicine (PM) is poised to become the standard of care in pharmaceutical therapy, necessitating a fundamental transformation in the design and development of innovative custom-made drug products. To date, a comprehensive review linking PM with practical personalized drug formulations is missing. This review attempts to provide an overview of state-of-the-art formulation approaches capable of translating PM evaluation and resulting recommendations (clinical research) into tailored drug products (non-clinical research) for real-world patients. Comprehensive literature searches in four scientific databases (Scopus, SciFinder, Web of Science, and PubMed) were performed. Current approaches to point-of-care PM formulations and needs-based locally distributed manufacturing presently under research & development (R&D) as alternatives to conventional large-scale manufacturing of one-size-fits-all drug products are discussed. The following methods were identified as the most promising PM formulation strategies: tablet splitting, liquid dispensing, compounding pharmacies, additive manufacturing, drug impregnation, drug extrusion, and orodispersible films (ODFs). The challenges and opportunities of current state-of-the-art formulation technologies that can enable making PM routinely accessible in practice settings will be discussed. Additionally, light will be shed on point-of-use manufacturing (Pharmacy on Demand) as an uncharted territory for PM and its pathway towards practical implementation.

3D printing for controlled release Pharmaceuticals: Current trends and future directions

In recent years, 3D printers have grown strongly in drug delivery and personalised medicine, being used more and more widely. In medicine, 3DP technology can advance personalised medicine and design dosage forms to regulate the drug release rate. This review gives an overview of the 3D printing for controlled-release pharmaceuticals, detailing the technical principles, common types (including extrusion, powder, liquid, and sheet lamination-based systems), drug release control mechanisms (e.g., dissolution and diffusion, osmosis, and swelling, partitioning and erosion, and targeting), and the advantages, status, and challenges. It discusses the future direction of the technology, including multidisciplinary cross-fertilisation and the advancement of personalised medicine. The technology has potential but faces many challenges such as cost, production capacity, materials, regulations, and quality control.

Enhancing Patient-Centric Drug Development: Coupling Hot Melt Extrusion with Fused Deposition Modeling and Pressure-Assisted Microsyringe Additive Manufacturing Platforms with Quality by Design

In recent years, with the increasing patient population, the need for complex and patient-centric medications has increased enormously. Traditional manufacturing techniques such as direct blending, high shear granulation, and dry granulation can be used to develop simple solid oral medications. However, it is well known that "one size fits all" is not true for pharmaceutical medicines. Depending on the age, sex, and disease state, each patient might need a different dose, combination of medicines, and drug release pattern from the medications. By employing traditional practices, developing patient-centric medications remains challenging and unaddressed. Over the last few years, much research has been conducted exploring various additive manufacturing techniques for developing on-demand, complex, and patient-centric medications. Among all the techniques, nozzle-based additive manufacturing platforms such as pressure-assisted microsyringe (PAM) and fused deposition modeling (FDM) have been investigated thoroughly to develop various medications. Both nozzle-based techniques involve the application of thermal energy. However, PAM can also be operated under ambient conditions to process semi-solid materials. Nozzle-based techniques can also be paired with the hot melt extrusion (HME) process for establishing a continuous manufacturing platform by employing various in-line process analytical technology (PAT) tools for monitoring critical process parameters (CPPs) and critical material attributes (CMAs) for delivering safe, efficacious, and quality medications to the patient population without compromising critical quality attributes (CQAs). This review covers an in-depth discussion of various critical parameters and their influence on product quality, along with a note on the continuous manufacturing process, quality by design, and future perspectives.

Development of 3D-printed dual-release fixed-dose combination through double-melt extrusion

This study aimed to develop a 3D-printed fixed-dose combination tablet featuring differential release of two drugs using double-melt extrusion (DME). The hot-melt extrusion (HME) process was divided into two steps to manufacture a single filament containing the two drugs. In Step I, a sustained-release matrix of acetaminophen (AAP) was obtained through HME at 190 °C using Eudragit® S100, a pH-dependent polymer with a high glass transition temperature. In Step II, a filament containing both sustained-release AAP from Step I and solubilized ibuprofen (IBF) was fabricated via HME at 110 °C using a mixture of hydroxy propyl cellulose (HPC-LF) and Eudragit® EPO, whose glass transition temperatures make them suitable for use in a 3D printer. A filament manufactured using DME was used to produce a cylindrical 3D-printed fixed-dose combination tablet with a diameter and height of 9 mm. To evaluate the release characteristics of the manufactured filament and 3D-printed tablet, dissolution tests were conducted for 10 h under simulated gastrointestinal tract conditions using the pH jump method with the United States Pharmacopeia apparatus II paddle method at 37 ± 0.5 °C and 50 rpm. Dissolution tests confirmed that both the sustained-release and solubilized forms of AAP and IBF within the filament and 3D-printed tablet exhibited distinct drug-release behaviors. The physicochemical properties of the filament and 3D-printed tablet were confirmed by thermogravimetric analysis, differential scanning calorimetry, powder X-ray diffraction, and Fourier-transform infrared spectroscopy. HME transforms crystalline drugs into amorphous forms, demonstrating their physicochemical stability. Scanning electron microscopy and confocal laser scanning microscopy indicated the presence of sustained AAP granules within the filament, confirming that the drugs were independently separated within the filament and 3D-printed tablets. Finally, sustained-release AAP and solubilized IBF were independently incorporated into the filaments using DME technology. Therefore, a dual-release 3D-printed fixed-dose combination was prepared using the proposed filament.

Transformative applications of additive manufacturing in biomedical engineering: bioprinting to surgical innovations

This paper delves into the diverse applications and transformative impact of additive manufacturing (AM) in biomedical engineering. A detailed analysis of various AM technologies showcases their distinct capabilities and specific applications within the medical field. Special emphasis is placed on bioprinting of organs and tissues, a revolutionary area where AM has the potential to revolutionize organ transplantation and regenerative medicine by fabricating functional tissues and organs. The review further explores the customization of implants and prosthetics, demonstrating how tailored medical devices enhance patient comfort and performance. Additionally, the utility of AM in surgical planning is examined, highlighting how printed models contribute to increased surgical precision, reduced operating times, and minimized complications. The discussion extends to the 3D printing of surgical instruments, showcasing how these bespoke tools can improve surgical outcomes. Moreover, the integration of AM in drug delivery systems, including the development of innovative drug-loaded implants, underscores its potential to enhance therapeutic efficacy and reduce side effects. It also addresses personalized prosthetic implants, regulatory frameworks, biocompatibility concerns, and the future potential of AM in global health and sustainable practices.

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.

Application of 3D printing in early phase development of pharmaceutical solid dosage forms

Three-dimensional printing (3DP) is an emerging technology, offering the possibility for the development of dose-customized, effective, and safe solid oral dosage forms (SODFs). Although 3DP has great potential, it does come with certain limitations, and the traditional drug manufacturing platforms remain the industry standard. The consensus appears to be that 3DP technology is expected to benefit personalized medicine the most, but that it is unlikely to replace conventional manufacturing for mass production. The 3DP method, on the other hand, could prove well-suited for producing small batches as an adaptive manufacturing technique for enabling adaptive clinical trial design for early clinical studies. The purpose of this review is to discuss recent advancements in 3DP technologies for SODFs and to focus on the applications for SODFs in the early clinical development stages, including a discussion of current regulatory challenges and quality controls.

Pediatric Formulations Developed by Extrusion-Based 3D Printing: From Past Discoveries to Future Prospects

Three-dimensional printing (3DP) technology in pharmaceutical areas is leading to a significant change in controlled drug delivery and pharmaceutical product development. Pharmaceutical industries and academics are becoming increasingly interested in this innovative technology due to its inherent inexpensiveness and rapid prototyping. The 3DP process could be established in the pharmaceutical industry to replace conventional large-scale manufacturing processes, particularly useful for personalizing pediatric drugs. For instance, shape, size, dosage, drug release and multi-drug combinations can be tailored according to the patient's needs. Pediatric drug development has a significant global impact due to the growing needs for accessible age-appropriate pediatric medicines and for acceptable drug products to ensure adherence to the prescribed treatment. Three-dimensional printing offers several significant advantages for clinical pharmaceutical drug development, such as the ability to personalize medicines, speed up drug manufacturing timelines and provide on-demand drugs in hospitals and pharmacies. The aim of this article is to highlight the benefits of extrusion-based 3D printing technology. The future potential of 3DP in pharmaceuticals has been widely shown in the last few years. This article summarizes the discoveries about pediatric pharmaceutical formulations which have been developed with extrusion-based technologies.

Rising role of 3D-printing in delivery of therapeutics for infectious disease

Modern drug delivery to tackle infectious disease has drawn close to personalizing medicine for specific patient populations. Challenges include antibiotic-resistant infections, healthcare associated infections, and customizing treatments for local patient populations. Recently, 3D-printing has become a facilitator for the development of personalized pharmaceutic drug delivery systems. With a variety of manufacturing techniques, 3D-printing offers advantages in drug delivery development for controlled, fine-tuned release and platforms for different routes of administration. This review summarizes 3D-printing techniques in pharmaceutics and drug delivery focusing on treating infectious diseases, and discusses the influence of 3D-printing design considerations on drug delivery platforms targeting these diseases. Additionally, applications of 3D-printing in infectious diseases are summarized, with the goal to provide insight into how future delivery innovations may benefit from 3D-printing to address the global challenges in infectious disease.

Strategies to improve the stability of amorphous solid dispersions in view of the hot melt extrusion (HME) method

Oral administration of drugs is preferred over other routes for several reasons: it is non-invasive, easy to administer, and easy to store. However, drug formulation for oral administration is often hindered by the drug's poor solubility, which limits its bioavailability and reduces its commercial value. As a solution, amorphous solid dispersion (ASD) was introduced as a drug formulation method that improves drug solubility by changing the molecular structure of the drugs from crystalline to amorphous. The hot melt extrusion (HME) method is emerging in the pharmaceutical industry as an alternative to manufacture ASD. However, despite solving solubility issues, ASD also exposes the drug to a high risk of crystallisation, either during processing or storage. Formulating a successful oral administration drug using ASD requires optimisation of the formulation, polymers, and HME manufacturing processes applied. This review presents some important considerations in ASD formulation, including strategies to improve the stability of the final product using HME to allow more new drugs to be formulated using this method.

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.

Development and Bioequivalence of 3D-Printed Medication at the Point-of-Care: Bridging the Gap Toward Personalized Medicine

Personalized medicine is currently hampered by the lack of flexible drug formulations. Especially for pediatric patients, manual compounding of personalized drug formulations by pharmacists is required. Three-Dimensional (3D) printing of medicines, which enables small-scale manufacturing at the point-of-care, can fulfill this unmet clinical need. This study investigates the feasibility of developing a 3D-printed tablet formulation at the point-of-care which complies to quality requirements for clinical practice, including bioequivalence. Development, manufacturing, and quality control of the 3D-printed tablets was performed at the manufacturing facility and laboratory of the department of Clinical Pharmacy and Toxicology at Leiden University Medical Center. Sildenafil was used as a model drug for the tablet formulation. Along with the 3D-printed tablets a randomized, an open-label, 2-period, crossover, single-dose clinical trial to assess bioequivalence was performed in healthy adults. Bioequivalence was established if areas under the plasma concentration curve from administration to the time of the last quantifiable concentration (AUC_0-t ) and maximum plasma concentration (C_max ) ratios were within the limits of 80.00-125.00%. The manufacturing process provided reproducible 3D-printed tablets that adhered to quality control requirements and were consequently used in the clinical trial. The clinical trial was conducted in 12 healthy volunteers. The 90% confidence intervals (CIs) of both AUC_0-t and C_max ratios were within bioequivalence limits (AUC_0-t 90% CI: 87.28-104.14; C_max 90% CI: 80.23-109.58). For the first time, we demonstrate the development of a 3D-printed tablet formulation at the point-of-care that is bioequivalent to its marketed originator. The 3D printing of personalized formulations is a disruptive technology for compounding, bridging the gap toward personalized medicine.

Recent Advances in the Applications of Additive Manufacturing (3D Printing) in Drug Delivery: A Comprehensive Review

There has been a tremendous increase in the investigations of three-dimensional (3D) printing for biomedical and pharmaceutical applications, and drug delivery in particular, ever since the US FDA approved the first 3D printed medicine, SPRITAM® (levetiracetam) in 2015. Three-dimensional printing, also known as additive manufacturing, involves various manufacturing techniques like fused-deposition modeling, 3D inkjet, stereolithography, direct powder extrusion, and selective laser sintering, among other 3D printing techniques, which are based on the digitally controlled layer-by-layer deposition of materials to form various geometries of printlets. In contrast to conventional manufacturing methods, 3D printing technologies provide the unique and important opportunity for the fabrication of personalized dosage forms, which is an important aspect in addressing diverse patient medical needs. There is however the need to speed up the use of 3D printing in the biopharmaceutical industry and clinical settings, and this can be made possible through the integration of modern technologies like artificial intelligence, machine learning, and Internet of Things, into additive manufacturing. This will lead to less human involvement and expertise, independent, streamlined, and intelligent production of personalized medicines. Four-dimensional (4D) printing is another important additive manufacturing technique similar to 3D printing, but adds a 4th dimension defined as time, to the printing. This paper aims to give a detailed review of the applications and principles of operation of various 3D printing technologies in drug delivery, and the materials used in 3D printing, and highlight the challenges and opportunities of additive manufacturing, while introducing the concept of 4D printing and its pharmaceutical applications.

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.

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

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

Role of Heteronucleants in Melt Crystallization of Crystalline Solid Dispersions

Few publications exist concerning polymorphic control during melt crystallization, particularly when employing heteronucleants. Here, the influence of a polymeric thin film (polyethylene terephthalate, PET) on the crystallization from melt of the polymorphic compound acetaminophen (ACM) in polyethylene glycol (PEG) was investigated. Molten ACM-PEG at different compositions was monitored using in situ Raman spectroscopy for nucleation induction time measurements and phase identification. Furthermore, X-ray diffraction (XRD) served to analyze the preferred orientation (PO) of the pastilles (solidified melt droplets) on PET-coated and uncoated substrates. The results indicate that PET-coated substrates qualitatively accelerate the nucleation of ACM form II (ACM II) in PEG compared to uncoated glass substrates. Additionally, the occurrence of ACM II in PEG was increased by an average of 10% when crystallized on PET-coated substrates compared to uncoated substrates. Overall, these results suggest that ACM can interact through hydrogen bonding with the PET-coated substrate, leading to faster nucleation. This investigation illustrates the effect of PET-coated substrates in the selective crystallization of ACM II in PEG as crystalline solid dispersions (CSDs). Ultimately, the results suggest the implementation of polymeric heteronucleants in melt crystallization processes, specifically, in advanced polymer-based formulation processes for the enhanced polymorphic form control of pharmaceutical compounds in CSDs.

4D prints of flexible dosage forms using thermoplastic polyurethane with hybrid shape memory effect

Thermoplastic polyurethanes are versatile materials due to their flexible and elastic properties. In research, medicine, and pharmacy, they are used in dosage forms, implants or as components of medical devices. To gain a deeper understanding of the influences on unfolding or expanding dosage forms, in this publication, 3D printing was used to produce differently shaped and foldable objects from various technical thermoplastic polyurethane filaments. The shape memory behaviour of the dosage forms was exploited to fold and package them in water-soluble hard gelatin capsules. The unfolding time and dimensional recovery of the 3D printed dosage forms were investigated as a function of material properties and shape. As an example, for the use of flexible dosage forms, 3D models have been designed so that their unfolded size is suitable for possible gastric retention. Depending on the shape and material, different unfolding behaviours could be shown. Over a storage period of 60 days, a time related stress on the 4D printed objects was evaluated, which possibly affects the unfolding process. The results of this work aim to be used to evaluate the behaviour of 3D printed unfolding and expanding dosage forms and how they may be suitable for the development of innovative sustained drug delivery concepts or medicinal devices. The basic principle of a hybrid shape memory effect used here could possibly be applied to other drug delivery strategies besides gastric retention.

An Insight into the Impact of Thermal Process on Dissolution Profile and Physical Characteristics of Theophylline Tablets Made through 3D Printing Compared to Conventional Methods

The dissolution profile is of great importance in drug delivery and is affected by the manufacturing method. Thus, it is important to study the influence of the thermal process on drug release in emerging technologies such as 3D printing-fused deposition modeling (FDM). For this purpose, the characteristics of 3D printed tablets were compared to those of tablets prepared by other thermal methods such as hot-melt extrusion (HME) and non-thermal methods such as physical mixture (PM). Theophylline was used as a drug model and blends of ethyl cellulose (EC) and hydroxypropyl cellulose (HPC) were used as a matrix former. The solid state of the drug in all formulations was investigated by differential scanning calorimetry, X-ray powder diffraction, and Fourier-transformed infrared spectroscopy. All studied tablets had the same weight and surface area/volume (SA/V). Dissolution data showed that, for some formulations, printed tablets interestingly had a faster release profile despite having the highest hardness values (>550 N) compared to HME and PM tablets. Porosity investigations showed that 100% infill printed tablets had the highest porosity (~20%) compared to HME (<10%) and PM tablets (≤11%). True density records were the lowest in printed tablets (~1.22 g/m3) compared to tablets made from both HME and PM methods (~1.26 g/m3), reflecting the possible increase in polymer specific volume while printing. This increase in the volume of polymer network may accelerate water and drug diffusion from/within the matrix. Thus, it is a misconception that the 3D printing process will always retard drug release based on increased tablet hardness. Hardness, porosity, density, solid-state of the drug, SA/V, weight, and formulation components are all factors contributing to the release profile where the total balance can either slow down or accelerate the release profile.

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

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

A 3D-Printed Polymer-Lipid-Hybrid Tablet towards the Development of Bespoke SMEDDS Formulations

3D printing is a rapidly growing area of interest within pharmaceutical science thanks to its versatility in creating different dose form geometries and drug doses to enable the personalisation of medicines. Research in this area has been dominated by polymer-based materials; however, for poorly water-soluble lipophilic drugs, lipid formulations present advantages in improving bioavailability. This study progresses the area of 3D-printed solid lipid formulations by providing a 3D-printed dissolvable polymer scaffold to compartmentalise solid lipid formulations within a single dosage form. This allows the versatility of different drugs in different lipid formulations, loaded into different compartments to generate wide versatility in drug release, and specific control over release geometry to tune release rates. Application to a range of drug molecules was demonstrated by incorporating the model lipophilic drugs; halofantrine, lumefantrine and clofazimine into the multicompartmental scaffolded tablets. Fenofibrate was used as the model drug in the single compartment scaffolded tablets for comparison with previous studies. The formulation-laden scaffolds were characterised using X-ray CT and dispersion of the formulation was studied using nephelometry, while release of a range of poorly water-soluble drugs into different gastrointestinal media was studied using HPLC. The studies show that dispersion and drug release are predictably dependent on the exposed surface area-to-volume ratio (SA:V) and independent of the drug. At the extremes of SA:V studied here, within 20 min of dissolution time, formulations with an SA:V of 0.8 had dispersed to between 90 and 110%, and completely released the drug, where as an SA:V of 0 yielded 0% dispersion and drug release. Therefore, this study presents opportunities to develop new dose forms with advantages in a polypharmacy context.

Performance and paroxetine stability in tablets manufactured by fused deposition modelling-based 3D printing

OBJECTIVES

The objective of this study was to develop a method for the preparation and characterization of paroxetine (PRX) tablets, obtained by coupling hot-melt extrusion and fused deposition modelling (FDM)-based three-dimensional printing (3DP) technology. The impact of the printing process parameters on the drug stability and on the tablets performance was assessed.

METHODS

Tablets were obtained by FDM of hot-melt extruded PRX-loaded filaments. Physicochemical, thermal, spectroscopic, diffractometric analysis and in-vitro dissolution tests of the intermediate products and the finished dosage forms were performed.

KEY FINDINGS

The characterization of printed tablets evidenced mass and dimensions uniformity, and consistency of drug content and dissolution profile. The formation of amorphous solid dispersions and interaction of formulation components throughout the manufacturing process were demonstrated. Layer thickness, printing temperature, printing and travelling speeds, and infill were the most impacting process parameters on both the physicochemical properties and the in-vitro performance of the 3D-printed tablets.

CONCLUSIONS

PRX tablets, meeting compendial limits, were manufactured by 3DP, envisaging their clinical use as individually designed dosage forms. The assessment of the impact of processing parameters on the printed tablets provided insights, which will ultimately allow streamlining of the 3D process set-up for quicker and easier production of patient-centric medicines.