Oral Fixed-Dose Combination Pharmaceutical Products: Industrial Manufacturing Versus Personalized 3D Printing

Revolutionizing fixed-dose combinations with long-acting microsphere

Combination therapy, involving the concurrent use of multiple medications, has become crucial for managing complex diseases with diverse pathological mechanisms. Fixed-Dose Combinations (FDCs) are formulated to leverage the synergistic effects of multiple drugs, thereby enhancing therapeutic outcomes. However, conventional FDCs typically maintain therapeutic effects for only up to 24 h and require frequent dosing, which often results in patient non-compliance and inconsistent treatment responses, especially in chronic diseases. This highlights the urgent need for long-acting FDCs that can provide sustained drug release over extended periods-weeks, months, or even years-thereby reducing dosing frequency and enhancing patient adherence. Microspheres, with their ability to encapsulate and release multiple medications in predefined patterns, are highly advantageous for developing long-acting FDC drugs. This review emphasizes the increasing demand for long-acting FDC drugs that ensure sustained drug release, reduce dosing frequency, and ultimately improve patient adherence. We also highlight the potential of microsphere technology, which enables precise encapsulation and sustained release of multiple medications, as a promising approach for revolutionizing long-acting FDCs with enhanced therapeutic outcomes.

Targeted Oral Fixed-Dose Combination of Amphotericin B-Miltefosine for Visceral Leishmaniasis

The incidence of visceral leishmaniasis (VL) remains a significant health threat in endemic countries. Fixed-dose combination (FDC) of amphotericin B (AmB) and miltefosine (MLT) is a promising strategy for treating VL, but the parenteral administration of AmB leads to severe side effects, limiting its use in clinical practice. Here, we developed novel FDC granules combining AmB in the core with a MLT coating using wet granulation followed by the fluidized bed technology. The granules maintained the crystalline structure of AmB throughout manufacturing, achieving an AmB loading of ∼20%. The MLT coating layer effectively sustained AmB release from 3 to 24 h following Korsmeyer-Peppas kinetics. The formulation demonstrated remarkable stability, maintaining >90% drug content for over a year at both 4 °C and room temperature under desiccated conditions. In vivo efficacy studies in Leishmania infantum-infected hamsters showed 65-80% reduction in parasite burden in spleen and liver, respectively, suggesting potential as an oral alternative to current VL treatments. Uncoated and coated granules demonstrated comparable performance in key aspects, including in vivo efficacy and long-term stability.

Prilling of crystallizable water-in-oil emulsions: Towards co-encapsulation of hydrophilic and lipophilic active ingredients within lipid microparticles

Multiparticulate drug delivery systems offer advantages in controlled release, dose flexibility, and personalized medicine. Fusion prilling, a process that produces spherical lipid-based microparticles through vibrating nozzles, is gaining interest in the field. This study aims to explore the use of fusion prilling to encapsulate crystallizable water-in-oil emulsions, enabling the incorporation of hydrophilic active pharmaceutical ingredients (APIs) within lipid matrices. Urea (highly water-soluble) and Erythromycin (poorly water-soluble) were selected as model compounds, solubilized in the aqueous and lipid phases, respectively. The first phase of the study evaluated lipid excipients for their suitability in prilling, ensuring microparticle consistency in shape, size, and stability. The second phase focused on characterizing microparticles notably in terms of structural organization and integrity. Results demonstrated successful encapsulation of both model compounds, with high efficiency, by omitting an additional emulsification step. Despite concerns over water evaporation during processing, microparticles remained stable for up to 14 months when stored at room temperature in a hermetically sealed container. This work highlights the potential of fusion prilling for multiparticulate drug delivery systems, even for formulating APIs with different solubility profiles. Future research should focus on optimizing the process for broader API incorporation.

Evaluating experimental, knowledge-based and computational cocrystal screening methods to advance drug-drug cocrystal fixed-dose combination development

Fixed-dose combinations (FDCs) offer significant advantages to patients and the pharmaceutical industry alike through improved dissolution profiles, synergistic effects and extended patent lifetimes. Identifying whether two active pharmaceutical ingredients have the potential to form a drug-drug cocrystal (DDC) or interact is an essential step in determining the most suitable type of FDC to formulate. The lack of coherent strategies to determine if two active pharmaceutical ingredients that can be co-administered can form a cocrystal, has significantly impacted DDC commercialisation. This review aims to accelerate the development of FDCs and DDCs by evaluating existing experimental, knowledge-based and computational cocrystal screening methods; the background of their development, their application in screening for cocrystals and DDCs, and their limitations are discussed. The evaluation provided in this review will act as a guide for selecting suitable screening methods to accelerate FDC development.

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.

Artificial Intelligence (AI) Applications in Drug Discovery and Drug Delivery: Revolutionizing Personalized Medicine

Artificial intelligence (AI) encompasses a broad spectrum of techniques that have been utilized by pharmaceutical companies for decades, including machine learning, deep learning, and other advanced computational methods. These innovations have unlocked unprecedented opportunities for the acceleration of drug discovery and delivery, the optimization of treatment regimens, and the improvement of patient outcomes. AI is swiftly transforming the pharmaceutical industry, revolutionizing everything from drug development and discovery to personalized medicine, including target identification and validation, selection of excipients, prediction of the synthetic route, supply chain optimization, monitoring during continuous manufacturing processes, or predictive maintenance, among others. While the integration of AI promises to enhance efficiency, reduce costs, and improve both medicines and patient health, it also raises important questions from a regulatory point of view. In this review article, we will present a comprehensive overview of AI's applications in the pharmaceutical industry, covering areas such as drug discovery, target optimization, personalized medicine, drug safety, and more. By analyzing current research trends and case studies, we aim to shed light on AI's transformative impact on the pharmaceutical industry and its broader implications for healthcare.

Innovative Pharmaceutical Techniques for Paediatric Dosage Forms: A Systematic Review on 3D Printing, Prilling/Vibration and Microfluidic Platform

The production of paediatric pharmaceutical forms represents a unique challenge within the pharmaceutical industry. The primary goal of these formulations is to ensure therapeutic efficacy, safety, and tolerability in paediatric patients, who have specific physiological needs and characteristics. In recent years, there has been a significant increase in attention towards this area, driven by the need to improve drug administration to children and ensure optimal and specific treatments. Technological innovation has played a crucial role in meeting these requirements, opening new frontiers in the design and production of paediatric pharmaceutical forms. In particular, three emerging technologies have garnered considerable interest and attention within the scientific and industrial community: 3D printing, prilling/vibration, and microfluidics. These technologies offer advanced approaches for the design, production, and customization of paediatric pharmaceutical forms, allowing for more precise dosage modulation, improved solubility, and greater drug acceptability. In this review, we delve into these cutting-edge technologies and their impact on the production of paediatric pharmaceutical forms. We analyse their potential, associated challenges, and recent developments, providing a comprehensive overview of the opportunities that these innovative methodologies offer to the pharmaceutical sector. We examine different pharmaceutical forms generated using these techniques, evaluating their advantages and disadvantages.

Geometry-Driven Fabrication of Mini-Tablets via 3D Printing: Correlating Release Kinetics with Polyhedral Shapes

The aim of this study was to fabricate mini-tablets of polyhedrons containing theophylline using a fused deposition modeling (FDM) 3D printer, and to evaluate the correlation between release kinetics models and their geometric shapes. The filaments containing theophylline, hydroxypropyl cellulose (HPC), and EUDRAGIT RS PO (EU) could be obtained with a consistent thickness through pre-drying before hot melt extrusion (HME). Mini-tablets of polyhedrons ranging from tetrahedron to icosahedron were 3D-printed using the same formulation of the filament, ensuring equal volumes. The release kinetics models derived from dissolution tests of the polyhedrons, along with calculations for various physical parameters (edge, SA: surface area, SA/W: surface area/weight, SA/V: surface area/volume), revealed that the correlation between the Higuchi model and the SA/V was the highest (R2 = 0.995). It was confirmed that using 3D- printing for the development of personalized or pediatric drug products allows for the adjustment of drug dosage by modifying the size or shape of the drug while maintaining or controlling the same release profile.

Perspectives on 3D printed personalized medicines for pediatrics

In recent years, the rapid advancement of three-dimensional (3D) printing technology has yielded distinct benefits across various sectors, including pharmaceuticals. The pharmaceutical industry has particularly experienced advantages from the utilization of 3D-printed medications, which have invigorated the development of tailored drug formulations. The approval of 3D-printed drugs by the U.S. Food and Drug Administration (FDA) has significantly propelled personalized drug delivery. Additionally, 3D printing technology can accommodate the precise requirements of pediatric drug dosages and the complexities of multiple drug combinations. This review specifically concentrates on the application of 3D printing technology in pediatric preparations, encompassing a broad spectrum of uses and refined pediatric formulations. It compiles and evaluates the fundamental principles associated with the application of 3D printing technology in pediatric preparations, including its merits and demerits, and anticipates its future progression. The objective is to furnish theoretical underpinning for 3D printing technology to facilitate personalized drug delivery in pediatrics and to advocate for its implementation in clinical settings.

Microparticles and multi-unit systems for advanced drug delivery

Microparticles have unique benefits in the formulation of multiparticulate and multi-unit type pharmaceutical dosage forms allowing improved drug safety and efficacy with favorable pharmacokinetics and patient centricity. On the other hand, the above advantages are served by high and well reproducible quality attributes of the medicinal product where even flexible design and controlled processability offer success as well as possible longer product life-cycle for the manufacturers. Moreover, the specific demands of patients can be taken into account, including simplified dosing regimens, flexible dosage, drug combinations, palatability, and ease of swallowing. In the more than 70 years since the first modified-release formulation appeared on the market, many new formulations have been marketed and many publications have appeared in the literature. More unique and newer pharmaceutical technologies and excipients have become available for producing tailor-made particles with micrometer dimensions and beyond. All these have contributed to the fact that the sub-units (e.g. minitablets, pellets, microspheres) that make up a multiparticulate system can vary widely in composition and properties. Some units have mucoadhesive properties and others can float to contribute to a suitable release profile that can be designed for the multiparticulate formula as a whole. Nowadays, there are some available formulations on the market, which are able to release the active substance even for several months (3 or 6 months depending on the type of treatment). In this review, the latest developments in technologies that have been used for a long time are presented, as well as innovative solutions such as the applicability of 3D printing to produce subunits of multiparticulate systems. Furthermore, the diversity of multiparticulate systems, different routes of administration are also presented, touching the ones which are capable of carrying the active substance as well as the relevant, commercially available multiparticle-based medical devices. The versatility in size from 1 µm and multiplicity of formulation technologies promise a solid foundation for the future applications of dosage form design and development.

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.

Fixed-Dose Combination Formulations in Solid Oral Drug Therapy: Advantages, Limitations, and Design Features

Whilst monotherapy is traditionally the preferred treatment starting point for chronic conditions such as hypertension and diabetes, other diseases require the use of multiple drugs (polytherapy) from the onset of treatment (e.g., human immunodeficiency virus acquired immunodeficiency syndrome, tuberculosis, and malaria). Successful treatment of these chronic conditions is sometimes hampered by patient non-adherence to polytherapy. The options available for polytherapy are either the sequential addition of individual drug products to deliver an effective multi-drug regimen or the use of a single fixed-dose combination (FDC) therapy product. This article intends to critically review the use of FDC drug therapy and provide an insight into FDC products which are already commercially available. Shortcomings of FDC formulations are discussed from multiple perspectives and research gaps are identified. Moreover, an overview of fundamental formulation considerations is provided to aid formulation scientists in the design and development of new FDC products.

Orthogonal Gelations to Synthesize Core-Shell Hydrogels Loaded with Nanoemulsion-Templated Drug Nanoparticles for Versatile Oral Drug Delivery

Hydrophobic active pharmaceutical ingredients (APIs) are ubiquitous in the drug development pipeline, but their poor bioavailability often prevents their translation into drug products. Industrial processes to formulate hydrophobic APIs are expensive, difficult to optimize, and not flexible enough to incorporate customizable drug release profiles into drug products. Here, a novel, dual-responsive gelation process that exploits orthogonal thermo-responsive and ion-responsive gelations is introduced. This one-step "dual gelation" synthesizes core-shell (methylcellulose-alginate) hydrogel particles and encapsulates drug-laden nanoemulsions in the hydrogel matrices. In situ crystallization templates drug nanocrystals inside the polymeric core, while a kinetically stable amorphous solid dispersion is templated in the shell. Drug release is explored as a function of particle geometry, and programmable release is demonstrated for various therapeutic applications including delayed pulsatile release and sequential release of a model fixed-dose combination drug product of ibuprofen and fenofibrate. Independent control over drug loading between the shell and the core is demonstrated. This formulation approach is shown to be a flexible process to develop drug products with biocompatible materials, facile synthesis, and precise drug release performance. This work suggests and applies a novel method to leverage orthogonal gel chemistries to generate functional core-shell hydrogel particles.

Co-Delivery of a High Dose of Amphotericin B and Itraconazole by Means of a Dry Powder Inhaler Formulation for the Treatment of Severe Fungal Pulmonary Infections

Over the past few decades, there has been a considerable rise in the incidence and prevalence of pulmonary fungal infections, creating a global health problem due to a lack of antifungal therapies specifically designed for pulmonary administration. Amphotericin B (AmB) and itraconazole (ITR) are two antifungal drugs with different mechanisms of action that have been widely employed in antimycotic therapy. In this work, microparticles containing a high dose of AmB and ITR (20, 30, and 40% total antifungal drug loading) were engineered for use in dry powder inhalers (DPIs) with an aim to improve the pharmacological effect, thereby enhancing the existing off-label choices for pulmonary administration. A Design of Experiment (DoE) approach was employed to prepare DPI formulations consisting of AmB-ITR encapsulated within γ-cyclodextrin (γ-CD) alongside functional excipients, such as mannitol and leucine. In vitro deposition indicated a favourable lung deposition pattern characterised by an upper ITR distribution (mass median aerodynamic diameter (MMAD) ~ 6 µm) along with a lower AmB deposition (MMAD ~ 3 µm). This offers significant advantages for treating fungal infections, not only in the lung parenchyma but also in the upper respiratory tract, considering that Aspergillus spp. can cause upper and lower airway disorders. The in vitro deposition profile of ITR and larger MMAD was related to the higher unencapsulated crystalline fraction of the drug, which may be altered using a higher concentration of γ-CD.

Feasibility study of the use of a homemade direct powder extrusion printer to manufacture printed tablets with an immediate release of a BCS II molecule

Among the various 3D printing techniques, FDM is the most studied in pharmaceutical research. However, it requires the fabrication of filaments with suitable mechanical properties using HME, which can be laborious and time-consuming. DPE has emerged as a single-step printing technique that can overcome FDM limits as it enables the direct printing of powder blends without the need of filaments. This study demonstrated the manufacturing of cylindrical-shaped printed tablets containing CBD, a BCS II molecule, with an immediate release. Different blends of PEO/E100 and PEO/SOL, each with 10 % of CBD, were printed and tested according to the Eur. Ph. for uncoated tablets. Each printed cylinder met the Eur. Ph. specifications for friability, mass variation and mass uniformity. However, only the E100-based formulations enabled a CBD immediate release, as formulations containing SOL formed a gel once in contact with the dissolution medium, reducing the drug dissolution rate.

Engineering of 3D printed personalized polypills for the treatment of the metabolic syndrome

Metabolic syndrome is a collection of abnormalities, including at least three of the following insulin resistance, hypertension, dyslipidemia, type 2 diabetes, obesity, inflammation, and non-alcoholic fatty liver disease. 3D printed solid dosage forms have emerged as a promising tool enabling the fabrication of personalized medicines and offering solutions that cannot be achieved by industrial mass production. Most attempts found in the literature to manufacture polypills for this syndrome contain just two drugs. However, most fixed-dose combination (FDC) products in clinical practice required the use of three or more drugs. In this work, Fused deposition modelling (FDM) 3D printing technology coupled with Hot-melt extrusion (HME) has been successfully applied in the manufacture of polypills containing nifedipine (NFD), as an antihypertensive drug, simvastatin (SMV), as an antihyperlipidemic drug, and gliclazide (GLZ) as an antiglycemic drug. Hanssen solubility parameters (HSPs) were utilized as predictors to guide the formation of amorphous solid dispersion between drug and polymer to ensure miscibility and enhanced oral bioavailability. The HSP varied from 18.3 for NFD, 24.6 for SMV, and 7.0 for GLZ while the total solubility parameter for the excipient mixture was 27.3^0.5. This allowed the formation of an amorphous solid dispersion in SMV and GLZ 3D printed tablets compared to NFD which was partially crystalline. Popypill showed a dual release profile combining a faster SMV release (< 6 h) with a 24 h sustained release for NDF and GLZ. This work demonstrated the transformation of FDC into dynamic dose-personalized polypills.

Paediatric Solid Oral Dosage Forms for Combination Products: Improving In Vitro Swallowability of Minitablets Using Binary Mixtures with Pellets

There is a growing interest in enhancing the acceptability of paediatric pharmaceutical formulations. Solid oral dosage forms (SODF) are being considered as an alternative to liquid formulations, but they may compromise palatability as large volumes may be required. We hypothesised that a binary mixture of paediatric SODF, designed to increase the formulation maximum packing fraction, could reduce the suspension viscosity and facilitate swallowing. Using the Paediatric Soft Robotic Tongue (PSRT) - an in vitro device inspired by the anatomy and physiology of 2-year-old children - we investigated the oral phase of swallowing for multi-particulate formulations, i.e., pellets (350 and 700 µm particles), minitablets (MTs, 1.8 mm), and their binary mixtures (BM), by evaluating oral swallowing time, the percentage of particles swallowed, and post-swallow residues. We also conducted a systematic analysis of the effect of feeding method, bolus volume, carrier type, particle size, and particle volume fraction on pellets swallowability. The results demonstrated that the introduction of pellets affected the flowing ability of the carriers, increasing shear viscosity. The size of the pellets did not appear to influence particle swallowability but raising the particle volume fraction (v.f.) above 10% resulted in a decrease in the percentage of particles swallowed. At v.f. 0.4, pellets were easier to swallow (+ 13.1%) than MTs, being the administration method used highly dependent on the characteristics of the multi-particulate formulation under consideration. Finally, mixing MTs with only 24% of pellets improved particle swallowability, achieving swallowing levels similar to those of pellets alone. Thus, combining SODF, i.e., MTs and pellets, improves MT swallowability, and offers new possibilities for adjusting product palatability, being particularly attractive for combination products.

3D Printing Technology as a Promising Tool to Design Nanomedicine-Based Solid Dosage Forms: Contemporary Research and Future Scope

3D printing technology in medicine is gaining great attention from researchers since the FDA approved the first 3D-printed tablet (Spritam®) on the market. This technique permits the fabrication of various types of dosage forms with different geometries and designs. Its feasibility in the design of different types of pharmaceutical dosage forms is very promising for making quick prototypes because it is flexible and does not require expensive equipment or molds. However, the development of multi-functional drug delivery systems, specifically as solid dosage forms loaded with nanopharmaceuticals, has received attention in recent years, although it is challenging for formulators to convert them into a successful solid dosage form. The combination of nanotechnology with the 3D printing technique in the field of medicine has provided a platform to overcome the challenges associated with the fabrication of nanomedicine-based solid dosage forms. Therefore, the major focus of the present manuscript is to review the recent research developments that involved the formulation design of nanomedicine-based solid dosage forms utilizing 3D printing technology. Utilization of 3D printing techniques in the field of nanopharmaceuticals achieved the successful transformation of liquid polymeric nanocapsules and liquid self-nanoemulsifying drug delivery systems (SNEDDS) to solid dosage forms such as tablets and suppositories easily with customized doses as per the needs of the individual patient (personalized medicine). Furthermore, the present review also highlights the utility of extrusion-based 3D printing techniques (Pressure-Assisted Microsyringe-PAM; Fused Deposition Modeling-FDM) to produce tablets and suppositories containing polymeric nanocapsule systems and SNEDDS for oral and rectal administration. The manuscript critically analyzes contemporary research related to the impact of various process parameters on the performance of 3D-printed solid dosage forms.

Implementation of Quality by Design (QbD) for development of bilayer tablets

Bilayer tablets offer various drug release profiles for individual drugs incorporated in each layer of a bilayer tablet, which is rarely achievable by conventional tablets. These tablets also help avoid physicochemical incompatibilities between drugs and excipients. Successful manufacturing of such more complex dosage forms depends upon screening of material attributes of API and excipients as well as optimization of processing parameters of individual unit operations of the manufacturing process that must be strictly monitored and controlled to obtain an acceptable drug product quality and performance in order to achieve safety and efficacy per regulatory requirements. Optimizing formulation attributes and manufacturing processes during critical stages, such as blending, granulation, pre-compression, and main compression, can help avoid problems such as weight variation, segregation, and delamination of individual layers, which are frequently faced during the production of bilayer tablets. The main objective of this review is to establish the basis for the implementation of Quality by Design (QbD) system principles for the design and development of bilayer tablets, encompassing the preliminary and systematic risk assessment of critical material attributes (CMAs) and critical process parameters (CPPs) with respect to in-process and finished product critical quality attributes (CQAs). Moreover, the applicability of the QbD methodology based on its purpose is discussed and complemented with examples of bilayer tablet technology.

Investigation of the degradation and in-situ amorphization of the enantiomeric drug escitalopram oxalate during Fused Deposition Modeling (FDM) 3D printing

Hot-melt extrusion (HME) and subsequent FDM 3D printing offer great potential opportunities in the formulation development and production of customized oral dosage forms with poorly soluble drugs. However, thermal stress within these processes can be challenging for thermo-sensitive drugs. In this work, three different formulations were prepared to investigate the degradation and the solid state of the thermo-sensitive and poorly soluble drug escitalopram oxalate (ESC-OX) during the two heat-intensive processes HME and FDM 3D printing. For this purpose, hydroxypropyl methyl cellulose (HPMC) and basic butylated methacrylate copolymer (bPMMA) were chosen as polymers. DSC and XRD measurements revealed that ESC-OX is amorphous in the HPMC based formulations in both, extrudates and 3D printed tablets. In contrast, in-situ amorphization of the drug from crystalline state in bPMMA filaments was observed during FDM 3D printing. With regard to the content, it was found that degradation of ESC-OX in extrudates with bPMMA could be avoided and in 3D printed tablets almost fully reduced. Furthermore, a possible conversion into the R-enantiomer in the formulation with bPMMA could be excluded using a chiral column. Compared to the commercial product Cipralex®, drug release from extrudates and tablets with bPMMA was slower but still qualified as immediate drug release.

Can amphotericin B and itraconazole be co-delivered orally? Tailoring oral fixed-dose combination coated granules for systemic mycoses

The incidence and prevalence of invasive fungal infections have increased significantly over the last few years, leading to a global health problem due to the lack of effective treatments. Amphotericin B (AmB) and itraconazole (ITR) are two antifungal drugs with different mechanisms of action. In this work, AmB and ITR have been formulated within granules to elicit an enhanced pharmacological effect, while enhancing the oral bioavailability of AmB. A Quality by Design (QbD) approach was utilised to prepare fixed-dose combination (FDC) granules consisting of a core containing AmB with functional excipients, such as inulin, microcrystalline cellulose (MCC), chitosan, sodium deoxycholate (NaDC) and Soluplus® and polyvinyl pyrrolidone (PVP), coated with a polymeric layer containing ITR with Soluplus® or a combination of Poloxamer 188 and hydroxypropyl methyl cellulose-acetyl succinate (HPMCAS). A Taguchi design of experiments (DoE) with 7 factors and 2 levels was carried out to understand the key factors impacting on the physicochemical properties of the formulation followed by a Box-Behnken design with 3 factors in 3 levels chosen to optimise the formulation parameters. The core of the FDC granules was obtained by wet granulation and later coated using a fluidized bed. In vitro antifungal efficacy was demonstrated by measuring the inhibition halo against different species of Candida spp., including C. albicans (24.19-30.48 mm), C. parapsilosis (26.38-27.84 mm) and C. krusei (11.48-17.92 mm). AmB release was prolonged from 3 to 24 h when the AmB granules were coated. In vivo in CD-1 male mice studies showed that these granules were more selective towards liver, spleen and lung compared to kidney (up to 5-fold more selective in liver, with an accumulation of 8.07 µg AmB/g liver after twice-daily 5 days administration of granules coated with soluplus-ITR), resulting in an excellent oral administration option in the treatment of invasive mycosis. Nevertheless, some biochemical alterations were found, including a decrease in blood urea nitrogen (∼17 g/dl) and alanine aminotransferase (<30 U/l) and an increase in the levels of bilirubin (∼0.2 mg/dl) and alkaline phosphatase (<80 U/l), which could be indicative of a liver failure. Once-daily regimen for 10 days can be a promising therapy.

3D Printing Technologies in Personalized Medicine, Nanomedicines, and Biopharmaceuticals

3D printing technologies enable medicine customization adapted to patients' needs. There are several 3D printing techniques available, but majority of dosage forms and medical devices are printed using nozzle-based extrusion, laser-writing systems, and powder binder jetting. 3D printing has been demonstrated for a broad range of applications in development and targeting solid, semi-solid, and locally applied or implanted medicines. 3D-printed solid dosage forms allow the combination of one or more drugs within the same solid dosage form to improve patient compliance, facilitate deglutition, tailor the release profile, or fabricate new medicines for which no dosage form is available. Sustained-release 3D-printed implants, stents, and medical devices have been used mainly for joint replacement therapies, medical prostheses, and cardiovascular applications. Locally applied medicines, such as wound dressing, microneedles, and medicated contact lenses, have also been manufactured using 3D printing techniques. The challenge is to select the 3D printing technique most suitable for each application and the type of pharmaceutical ink that should be developed that possesses the required physicochemical and biological performance. The integration of biopharmaceuticals and nanotechnology-based drugs along with 3D printing ("nanoprinting") brings printed personalized nanomedicines within the most innovative perspectives for the coming years. Continuous manufacturing through the use of 3D-printed microfluidic chips facilitates their translation into clinical practice.

Review on Starter Pellets: Inert and Functional Cores

A significant proportion of pharmaceuticals are now considered multiparticulate systems. Modified-release drug delivery formulations can be designed with engineering precision, and patient-centric dosing can be accomplished relatively easily using multi-unit systems. In many cases, Multiple-Unit Pellet Systems (MUPS) are formulated on the basis of a neutral excipient core which may carry the layered drug surrounded also by functional coating. In the present summary, commonly used starter pellets are presented. The manuscript describes the main properties of the various nuclei related to their micro- and macrostructure. In the case of layered pellets formed based on different inert pellet cores, the drug release mechanism can be expected in detail. Finally, the authors would like to prove the industrial significance of inert cores by presenting some of the commercially available formulations.

Development of Advanced 3D-Printed Solid Dosage Pediatric Formulations for HIV Treatment

The combination of lopinavir/ritonavir remains one of the first-line therapies for the initial antiretroviral regimen in pediatric HIV-infected children. However, the implementation of this recommendation has faced many challenges due to cold-chain requirements, high alcohol content, and unpalatability for ritonavir-boosted lopinavir syrup. In addition, the administration of crushed tablets has shown a detriment for the oral bioavailability of both drugs. Therefore, there is a clinical need to develop safer and better formulations adapted to children’s needs. This work has demonstrated, for the first time, the feasibility of using direct powder extrusion 3D printing to manufacture personalized pediatric HIV dosage forms based on 6 mm spherical tablets. H-bonding between drugs and excipients (hydroxypropyl methylcellulose and polyethylene glycol) resulted in the formation of amorphous solid dispersions with a zero-order sustained release profile, opposite to the commercially available formulation Kaletra, which exhibited marked drug precipitation at the intestinal pH.

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.

Patient Centricity Driving Formulation Innovation: Improvements in Patient Care Facilitated by Novel Therapeutics and Drug Delivery Technologies

Innovative formulation technologies can play a crucial role in transforming a novel molecule to a medicine that significantly enhances patients' lives. Improved mechanistic understanding of diseases has inspired researchers to expand the druggable space using new therapeutic modalities such as interfering RNA, protein degraders, and novel formats of monoclonal antibodies. Sophisticated formulation strategies are needed to deliver the drugs to their sites of action and to achieve patient centricity, exemplified by messenger RNA vaccines and oral peptides. Moreover, access to medical information via digital platforms has resulted in better-informed patient groups that are requesting consideration of their needs during drug development. This request is consistent with health authority efforts to upgrade their regulations to advance age-appropriate product development for patients. This review describes formulation innovations contributingto improvements in patient care: convenience of administration, preferred route of administration, reducing dosing burden, and achieving targeted delivery of new modalities.

3D Printing of Thermo-Sensitive Drugs

Three-dimensional (3D) printing is among the rapidly evolving technologies with applications in many sectors. The pharmaceutical industry is no exception, and the approval of the first 3D-printed tablet (Spiratam^®) marked a revolution in the field. Several studies reported the fabrication of different dosage forms using a range of 3D printing techniques. Thermosensitive drugs compose a considerable segment of available medications in the market requiring strict temperature control during processing to ensure their efficacy and safety. Heating involved in some of the 3D printing technologies raises concerns regarding the feasibility of the techniques for printing thermolabile drugs. Studies reported that semi-solid extrusion (SSE) is the commonly used printing technique to fabricate thermosensitive drugs. Digital light processing (DLP), binder jetting (BJ), and stereolithography (SLA) can also be used for the fabrication of thermosensitive drugs as they do not involve heating elements. Nonetheless, degradation of some drugs by light source used in the techniques was reported. Interestingly, fused deposition modelling (FDM) coupled with filling techniques offered protection against thermal degradation. Concepts such as selection of low melting point polymers, adjustment of printing parameters, and coupling of more than one printing technique were exploited in printing thermosensitive drugs. This systematic review presents challenges, 3DP procedures, and future directions of 3D printing of thermo-sensitive formulations.

Supersaturating drug delivery systems containing fixed-dose combination of two antihypertensive drugs: Formulation, in vitro evaluation and molecular metadynamics simulations

The purpose of this study was to associate the poorly water-soluble antihypertensive drugs candesartan cilexetil (CC) and hydrochlorothiazide (HCTZ) as fixed-dose combination, in the form of ternary Amorphous Solid Dispersions (ASD), using hydroxypropylmethylcellulose acetate succinate (HPMCAS) type M as polymeric carrier. The potential of the system to generate and to maintain supersaturation of both drugs was also evaluated. The ASDs were prepared by ball milling technique and solid-state characterization was performed by differential scanning calorimetry (DSC), Fourier transformed infrared spectroscopy (FTIR) and X-ray powder diffraction (XRPD). Interaction between drugs and polymer in solid-state was evaluated by molecular metadynamics simulations. In vitro supersaturation profiles were determined in biorelevant medium. Physicochemical stability of ASDs was also evaluated under different storage conditions. Amorphization of both drugs was confirmed by solid-state characterization techniques. Molecular metadynamics simulations indicated that CC has stronger interaction with HMPCAS than HCTZ. In vitro supersaturation studies have shown that ternary ASDs could generate and maintain supersaturation of both drugs in biorelevant medium. The polymer reduced the desupersaturation of both drugs. Ternary ASDs also showed physicochemical stability over a period of 90 days, demonstrating the potential of the polymer in reducing the drugs recrystallization over the time. Ternary ASDs of CC, HCTZ and HPMCAS can be considered a promising system to associate the drugs as fixed-dose combinations. Also, these systems generate and maintain supersaturation of both drugs in biorelevant medium, with great storage stability. HPMCAS M was a good carrier for reducing the desupersaturation of associated HCTZ and CC.

Advances in powder bed fusion 3D printing in drug delivery and healthcare

Powder bed fusion (PBF) is a 3D printing method that selectively consolidates powders into 3D objects using a power source. PBF has various derivatives; selective laser sintering/melting, direct metal laser sintering, electron beam melting and multi-jet fusion. These technologies provide a multitude of benefits that make them well suited for the fabrication of bespoke drug-laden formulations, devices and implants. This includes their superior printing resolution and speed, and ability to produce objects without the need for secondary supports, enabling them to precisely create complex products. Herein, this review article outlines the unique applications of PBF 3D printing, including the main principles underpinning its technologies and highlighting their novel pharmaceutical and biomedical applications. The challenges and shortcomings are also considered, emphasising on their effects on the 3D printed products, whilst providing a forward-thinking view.

How to Obtain the Maximum Properties Flexibility of 3D Printed Ketoprofen Tablets Using Only One Drug-Loaded Filament?

The flexibility of dose and dosage forms makes 3D printing a very interesting tool for personalized medicine, with fused deposition modeling being the most promising and intensively developed method. In our research, we analyzed how various types of disintegrants and drug loading in poly(vinyl alcohol)-based filaments affect their mechanical properties and printability. We also assessed the effect of drug dosage and tablet spatial structure on the dissolution profiles. Given that the development of a method that allows the production of dosage forms with different properties from a single drug-loaded filament is desirable, we developed a method of printing ketoprofen tablets with different dose and dissolution profiles from a single feedstock filament. We optimized the filament preparation by hot-melt extrusion and characterized them. Then, we printed single, bi-, and tri-layer tablets varying with dose, infill density, internal structure, and composition. We analyzed the reproducibility of a spatial structure, phase, and degree of molecular order of ketoprofen in the tablets, and the dissolution profiles. We have printed tablets with immediate- and sustained-release characteristics using one drug-loaded filament, which demonstrates that a single filament can serve as a versatile source for the manufacturing of tablets exhibiting various release characteristics.

Enabling modular dosage form concepts for individualized multidrug therapy: Expanding the design window for poorly water-soluble drugs

Multidrug dosage forms (aka combination dosage forms, polypills, etc.) create value for patients through reduced pill burdens and simplified administration to improve adherence to therapy. Enhanced flexibility of multidrug dosage forms would provide further opportunities to better match emerging needs for individualized therapy. Through modular dosage form concepts, one approach to satisfy these needs is to adapt multidrug dosage forms to a wider variety of drugs, each with a variety of doses and release profiles. This study investigates and technically explores design requirements for extending the capability of modular multidrug dosage form concepts towards individualization. This builds on our recent demonstration of independent tailoring of dose and drug release, which is here extended towards poorly water-soluble drugs. The challenging design requirement of carrying higher drug loads in smaller volumes to accommodate multiple drugs at their clinical dose is here met regarding dose and release performance. With a modular concept, we demonstrate high precision (<5% RSD) in dose and release performance of individual modules containing felodipine or naproxen in Kollidon VA64 at both a wide drug loading range (5% w/w and 50% w/w drug) and a small module size (3.6 mg). In a forward-looking design-based discussion, further requirements are addressed, emphasizing that reproducible individual module performance is predictive of dosage form performance, provided the modules are designed to act independently. Therefore, efforts to incorporate progressively higher drug loads within progressively smaller module volumes will be crucial to extend the design window further towards full flexibility of future dosage forms for individualized multidrug therapy.

3D printed spherical mini-tablets: Geometry versus composition effects in controlling dissolution from personalised solid dosage forms

Oral dosage forms are by far the most common prescription and over-the-counter pharmaceutical dosage forms used worldwide. However, many patients suffer from adverse effects caused by their use of "one-size fits all" mass produced commercially available solid dosage forms, whereby they do not receive dedicated medication or dosage adjusted to their specific needs. The development of 3D printing paves the way for personalised medicine. This work focuses on personalised therapies for hypertensive patients using nifedipine as the model drug. 3D printed full solid and channelled spherical mini-tablets with enhanced surface area (1.6-fold higher) were printed using modified PVA commercial filaments loaded by passive diffusion (PD), and Kollidon VA64 (KVA) and ethylcellulose (EC) based filaments prepared by hot-melt extrusion (HME). Drug loading ranged from 3.7% to 60% based on the employed technique, with a 13-fold higher drug loading achieved with the HME compared to PD. Composition was found to have a more significant impact on drug dissolution than geometry and surface area. Both KVA and EC-based formulations exhibited a biphasic zero-order drug-release profile. Physicochemical characterization revealed that nifedipine was in the amorphous form in the KVA-based end-products which led to a greater dissolution control over a 24 h period compared to the EC-based formulations that exhibited low levels of crystallinity by PXRD. The proposed 3D printed spherical mini-tablets provide a versatile technology for personalised solid dosage forms with high drug loading and dissolution control, easily adaptable to patient and disease needs.

Salts, solvates and hydrates of the multi-kinase inhibitor drug pazopanib with hydroxybenzoic acids

Eight cocrystal-salts of the multi-kinase drug pazopanib with hydroxybenzoic acids are sustained by the strong, ionic aminopyridinium⋯carboxylate heterosynthon of N–H⋯O hydrogen bonds between the carboxylic acid donor and amino-pyrimidine acceptor.

Tailoring Atomoxetine Release Rate from DLP 3D-Printed Tablets Using Artificial Neural Networks: Influence of Tablet Thickness and Drug Loading

Various three-dimensional printing (3DP) technologies have been investigated so far in relation to their potential to produce customizable medicines and medical devices. The aim of this study was to examine the possibility of tailoring drug release rates from immediate to prolonged release by varying the tablet thickness and the drug loading, as well as to develop artificial neural network (ANN) predictive models for atomoxetine (ATH) release rate from DLP 3D-printed tablets. Photoreactive mixtures were comprised of poly(ethylene glycol) diacrylate (PEGDA) and poly(ethylene glycol) 400 in a constant ratio of 3:1, water, photoinitiator and ATH as a model drug whose content was varied from 5% to 20% (w/w). Designed 3D models of cylindrical shape tablets were of constant diameter, but different thickness. A series of tablets with doses ranging from 2.06 mg to 37.48 mg, exhibiting immediate- and modified-release profiles were successfully fabricated, confirming the potential of this technology in manufacturing dosage forms on demand, with the possibility to adjust the dose and release behavior by varying drug loading and dimensions of tablets. DSC (differential scanning calorimetry), XRPD (X-ray powder diffraction) and microscopic analysis showed that ATH remained in a crystalline form in tablets, while FTIR spectroscopy confirmed that no interactions occurred between ATH and polymers.

Haptic Evaluation of 3D-printed Braille-encoded Intraoral Films

The three-dimensional (3D) printing technology has recently emerged in the pharmaceutical field, providing an array of applications for individualized dosing and elaborate formulation designs. However, an alternative asset of the 3D printing technology is the capability to imprint haptic identifiers directly onto the surface of the formulations. This approach can generate novel design concepts, that will serve specific populations for identifying the right treatment regimen, i.e., visually impaired people. Toward this direction, the fused deposition modelling (FDM) technique was investigated for manufacturing intraoral films and incorporating Braille characters on the available area. The films comprised a drug-loaded compartment and a backing layer, which are typical structural characteristics for buccal delivery. A hydrophilic polymer, i.e., hydroxypropyl methylcellulose, provided the polymer matrix for both compartments, whereas ketoprofen was incorporated in the study as model drug. The Braille-encoded texts were designed on top of the backing layer, complying with the Marburg Medium spacing convention for pharmaceutical Braille. Moreover, modifications on the standard spacing and dimension parameters were applied, to investigate the accuracy and repeatability of the FDM process. The fabricated films were subjected to a haptic evaluation study with the aid of visually impaired individuals, to assess the readability of the 3D-printed Braille-encoded text. The outcomes of the study highlighted the capacity of the FDM technology in combining novel manufacturing concepts for individualized therapies with customized services that can be provided to specific populations, as in the case of people with visual impairment.

Digital Light Processing (DLP) 3D Printing of Atomoxetine Hydrochloride Tablets Using Photoreactive Suspensions

Three-dimensional (3D) printing technologies are based on successive material printing layer-by-layer and are considered suitable for the production of dosage forms customized for a patient’s needs. In this study, tablets of atomoxetine hydrochloride (ATH) have been successfully fabricated by a digital light processing (DLP) 3D printing technology. Initial materials were photoreactive suspensions, composed of poly(ethylene glycol) diacrylate 700 (PEGDA 700), poly(ethylene glycol) 400 (PEG 400), photoinitiator and suspended ATH. The amount of ATH was varied from 10.00 to 25.00% (w/w), and a range of doses from 12.21 to 40.07 mg has been achieved, indicating the possibility of personalized therapy. The rheological characteristics of all photoreactive suspensions were appropriate for the printing process, while the amount of the suspended particles in the photoreactive suspensions had an impact on the 3D printing process, as well as on mechanical and biopharmaceutical characteristics of tablets. Only the formulation with the highest content of ATH had significantly different tensile strength compared to other formulations. All tablets showed sustained drug release during at least the 8h. ATH crystals were observed with polarized light microscopy of photoreactive suspensions and the cross-sections of the tablets, while no interactions between ATH and polymers were detected by FT-IR spectroscopy.

Independent Tailoring of Dose and Drug Release via a Modularized Product Design Concept for Mass Customization

Independent individualization of multiple product attributes, such as dose and drug release, is a crucial overarching requirement of pharmaceutical products for individualized therapy as is the unified integration of individualized product design with the processes and production that drive patient access to such therapy. Individualization intrinsically demands a marked increase in the number of product variants to suit smaller, more stratified patient populations. One established design strategy to provide enhanced product variety is product modularization. Despite existing customized and/or modular product design concepts, multifunctional individualization in an integrated manner is still strikingly absent in pharma. Consequently, this study aims to demonstrate multifunctional individualization through a modular product design capable of providing an increased variety of release profiles independent of dose and dosage form size. To further exhibit that increased product variety is attainable even with a low degree of product modularity, the modular design was based upon a fixed target dosage form size of approximately 200 mm3 comprising two modules, approximately 100 mm3 each. Each module contained a melt-extruded and molded formulation of 40% w/w metoprolol succinate in a PEG1500 and Kollidon® VA64 erodible hydrophilic matrix surrounded by polylactic acid and/or polyvinyl acetate as additional release rate-controlling polymers. Drug release testing confirmed the generation of predictable, combined drug release kinetics for dosage forms, independent of dose, based on a product's constituent modules and enhanced product variety through a minimum of six dosage form release profiles from only three module variants. Based on these initial results, the potential of the reconfigurable modular product design concept is discussed for unified integration into a pharmaceutical mass customization/mass personalization context.