Inkjet printing of paracetamol and indomethacin using electromagnetic technology: Rheological compatibility and polymorphic selectivity

Enhancing antioxidant delivery through 3D printing: a pathway to advanced therapeutic strategies

The rapid advancement of 3D printing has transformed industries, including medicine and pharmaceuticals. Integrating antioxidants into 3D-printed structures offers promising therapeutic strategies for enhanced antioxidant delivery. This review explores the synergistic relationship between 3D printing and antioxidants, focusing on the design and fabrication of antioxidant-loaded constructs. Incorporating antioxidants into 3D-printed matrices enables controlled release and localized delivery, improving efficacy while minimizing side effects. Customization of physical and chemical properties allows tailoring of antioxidant release kinetics, distribution, and degradation profiles. Encapsulation techniques such as direct mixing, coating, and encapsulation are discussed. Material selection, printing parameters, and post-processing methods significantly influence antioxidant release kinetics and stability. Applications include wound healing, tissue regeneration, drug delivery, and personalized medicine. This comprehensive review aims to provide insights into 3D printing-assisted antioxidant delivery systems, facilitating advancements in medicine and improved patient outcomes for oxidative stress-related disorders.

Flexible Organic Electronic Ion Pump Fabricated Using Inkjet Printing and Microfabrication for Precision In Vitro Delivery of Bupivacaine

The organic electronic ion pump (OEIP) is an on-demand electrophoretic drug delivery device, that via electronic to ionic signal conversion enables drug delivery without additional pressure or volume changes. The fundamental component of OEIPs is their polyelectrolyte membranes which are shaped into ionic channels that conduct and deliver ionic drugs, with high spatiotemporal resolution. The patterning of these membranes is essential in OEIP devices and is typically achieved using laborious microprocessing techniques. Here, the development of an inkjet printable formulation of polyelectrolyte is reported, based on a custom anionically functionalized hyperbranched polyglycerol (i-AHPG). This polyelectrolyte ink greatly simplifies the fabrication process and is used in the production of free-standing OEIPs on flexible polyimide (PI) substrates. Both i-AHPG and the OEIP devices are characterized, exhibiting favorable iontronic characteristics of charge selectivity and the ability to transport aromatic compounds. Further, the applicability of these technologies is demonstrated by the transport and delivery of the pharmaceutical compound bupivacaine to dorsal root ganglion cells with high spatial precision and effective nerve blocking, highlighting the applicability of these technologies for biomedical scenarios.

Needles to Spheres: Evaluation of inkjet printing as a particle shape enhancement tool

Active pharmaceutical ingredients (APIs) often reveal shapes challenging to process, e.g. acicular structures, and exhibit reduced bioavailability induced by slow dissolution rate. Leveraging the API particles' surface and bulk properties offers an attractive pathway to circumvent these challenges. Inkjet printing is an attractive processing technique able to tackle these limitations already in initial stages when little material is available, while particle properties are maintained over the entire production scale. Additionally, it is applicable to a wide range of formulations and offers the possibility of co-processing with a variety of excipients to improve the API's bioavailability. This study addresses the optimization of particle shapes for processability enhancement and demonstrates the successful application of inkjet printing to engineer spherical lacosamide particles, which are usually highly acicular. By optimizing the ink formulation, adapting the substrate-liquid interface and tailoring the heat transfer to the particle, spherical particles in the vicinity of 100 µm, with improved flow properties compared to the bulk material, were produced. Furthermore, the particle size was tailored reproducibly by adjusting the deposited ink volume per cycle and the number of printing cycles. Therefore, the present study shows a novel, reliable, scalable and economical strategy to overcome challenging particle morphologies by co-processing an API with suitable excipients.

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.

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.

Crystallization of Form II Paracetamol with the Assistance of Carboxylic Acids toward Batch and Continuous Processes

Form II paracetamol has captured the interest of researchers due to its improved compressibility. However, its low stability has made it difficult to be produced on a large scale with good reproducibility. In the present study, the selective polymorphic formation of paracetamol was carried out by cooling crystallization with four types of additives: adipic acid, fumaric acid, oxalic acid, and succinic acid. It was found that: (1) the more additives that were added, the higher the probability of forming Form II paracetamol; (2) Form II paracetamol could be induced by seeding the paracetamol aqueous solution with Form II paracetamol and fumaric acid crystals, and not the other three carboxylic acids; (3) a new solution complex of paracetamol–oxalic acid, evidenced by the solubility diagram, was responsible for the selective nucleation of Form II paracetamol in the oxalic acid aqueous solution; and (4) the range of the degree of supersaturation for nucleating Form II paracetamol was extended with the assistance of oxalic acid or fumaric acid. In large-scale crystallization, Form II paracetamol was produced by the continuous crystallization of 44 mg of paracetamol/mL in 50 wt% of fumaric acid aqueous solution with a flow rate of 150 mL/min.

Binder jetting 3D printing of challenging medicines: from low dose tablets to hydrophobic molecules

Increasing access to additive manufacturing technologies utilising easily available desktop devices opened novel ways for formulation of personalized medicines. It is, however, challenging to propose a flexible and robust formulation platform which can be used for fabrication of tailored solid dosage forms composed of APIs with different properties (e.g., hydrophobicity) without extensive optimization. This manuscript presents a strategy for formulation of fast dissolving tablets using binder jetting (BJ) technology. The approach is demonstrated using two model APIs: hydrophilic quinapril hydrochloride (QHCl, logP = 1.4) and hydrophobic clotrimazole (CLO, logP = 5.4). The proposed printing method uses inexpensive well known and easily available FDA approved pharmaceutical excipients. The obtained model tablets had uniform content of the drug, excellent mechanical properties and highly porous structure resulting in short disintegration time and fast dissolution rate. The tablets could be scaled and obtained in predesigned shapes and sizes. The proposed method may find its application in the early stages of drug development where high flexibility of the formulation is required and the amount of available API is limited.

3D Printing as a Promising Tool in Personalized Medicine

Personalized medicine has the potential to revolutionize the healthcare sector, its goal being to tailor medication to a particular individual by taking into consideration the physiology, drug response, and genetic profile of that individual. There are many technologies emerging to cause this paradigm shift from the conventional "one size fits all" to personalized medicine, the major one being three-dimensional (3D) printing. 3D printing involves the establishment of a three-dimensional object, in a layer upon layer manner using various computer software. 3D printing can be used to construct a wide variety of pharmaceutical dosage forms varying in shape, release profile, and drug combination. The major technological platforms of 3D printing researched on in the pharmaceutical sector include inkjet printing, binder jetting, fused filament fabrication, selective laser sintering, stereolithography, and pressure-assisted microsyringe. A possible future application of this technology could be in a clinical setting, where prescriptions could be dispensed based on individual needs. This manuscript points out the various 3D printing technologies and their applications in research for fabricating pharmaceutical products, along with their pros and cons. It also presents its potential in personalized medicine by individualizing the dose, release profiles, and incorporating multiple drugs in a polypill. An insight on how it tends to various populations is also provided. An approach of how it can be used in a clinical setting is also highlighted. Also, various challenges faced are pointed out, which must be overcome for the success of this technology in personalized medicine.

Development and Characterization of Inkjet Printed Edible Films for Buccal Delivery of B-Complex Vitamins

Buccal films containing two vitamins, i.e., thiamine hydrochloride (THCl) and nicotinic acid (NA), were fabricated via two-dimensional (2D) inkjet printing. For the preparation of buccal films, solubility studies and rheological evaluations were conducted in distilled water and propylene-glycol (PG) as main solvent and viscosity/surface tension modifier, respectively. The increased solubility in the solvents' mixture indicated that manufacturing of several doses of the THCl and NA is achievable. Various doses were deposited onto sugar-sheet substrates, by increasing the number of printing passes. The physiochemical characterization (SEM, DSC, FTIR) revealed that inkjet printing does not affect the solid state of the matrix. Water uptake studies were conducted, to compare the different vitamin-loaded formulations. The in vitro release studies indicated the burst release of both vitamins within 10 min, a preferable feature for buccal administration. The in vitro permeation studies indicated that higher concentrations of the vitamins onto the sugar sheet improved the in vitro permeation performance of printed formulations.

Additive Manufacturing Technologies for Drug Delivery Applications

Patient to patient variability is one of the issues when administering medications to individuals with different health conditions, pharmacokinetic, age, fitness, gender, and race. This requires introducing smart and personalised drug delivery systems with controlled release profile manufactured using novel approaches. Additive manufacturing (AM) provides opportunities such as full customisation, design freedom, and on-site manufacturing, and materials recycling. As a result, the academic and industrial demand for additive manufacturing for drug delivery has been continuously increasing and showing impressive results for a wide range of products. This paper provides an extensive overview of AM technologies and their applications for drug delivery. The review discusses AM technologies including their working principles, processed materials, as well as current progress in drug delivery to produce personalized dosages for every patient with controlled release profile. AM potentials, industrial scale, and challenges are investigated with regards to practice and industrial applications. The paper covers novel possibilities of AM technologies and their pharmaceuticals applications, which indicate a promising healthcare future.

A Pediatrics Utilization Study in The Netherlands to Identify Active Pharmaceutical Ingredients Suitable for Inkjet Printing on Orodispersible Films

Background: The use of medication in pediatrics, children aged 0–5 years, was explored so as to identify active pharmaceutical ingredients (APIs) suitable for inkjet printing on a plain orodispersible film (ODF) formulation in a pharmacy. Methods: The database IADB.nl, containing pharmacy dispensing data from community pharmacies in the Netherlands, was used to explore medication use in the age group of 0–5 years old, based on the Anatomical Therapeutic Chemical classification code (ATC code). Subsequently, a stepwise approach with four exclusion steps was used to identify the drug candidates for ODF formulation development. Results: there were 612 Active Pharmaceutical Ingredients (APIs) that were dispensed to the target group, mostly antibiotics. Of the APIs, 221 were not registered for pediatrics, but were used off-label. After the exclusion steps, 34 APIs were examined regarding their suitability for inkjet printing. Almost all of the APIs were sparingly water soluble to practically insoluble. Conclusion: Pharmaceutical inkjet printing is a suitable new technique for ODF manufacturing for pediatric application, however the maximal printed dose as found in the literature remained low. From the selected candidates, only montelukast shows a sufficiently high water-solubility to prepare a water-based solution. To achieve higher drug loads per ODF is ambitious, but is theoretically possible by printing multiple layers, using highly water-soluble APIs or highly loaded suspensions.

Next Steps in 3D Printing of Fast Dissolving Oral Films for Commercial Production

3D printing technique has been utilised to develop novel and complex drug delivery systems that are almost impossible to produce by employing conventional formulation techniques. For example, this technique may be employed to produce tablets or Fast Dissolving oral Films (FDFs) with multilayers of active ingredients, which are personalised to patient's needs. In this article, we compared the production of FDFs by 3D printing to conventional methods such as solvent casting. Then, we evaluated the need for novel methods of producing fast dissolving oral films, and why 3D printing may be able to meet the shortfalls of FDF production. The challenges of producing 3D printed FDFs are identified at commercial scale by referring to the identification of suitable materials, hardware, qualitycontrol tests and Process Analytical Technology. In this paper, we discuss that the FDF market will grow to more than $1.3 billion per annum in the next few years and 3D printing of FDFs may share part of this market. Although companies are continuing to invest in technologies, which provide alternatives to standard drug delivery systems, the market for thin-film products is already well established. Market entry for a new technology such as 3D printing of FDFs will, therefore, be hard, unless, this technology proves to be a game changer. A few approaches are suggested in this paper.

Engineering approaches to studying cancer cell migration in three-dimensional environments

Cancer is one of the most devastating diseases of our time, with 17 million new cancer cases and 9.5 million cancer deaths in 2018 worldwide. The mortality associated with cancer results primarily from metastasis, i.e. the spreading of cancer cells from the primary tumour to other organs. The invasion and migration of cells through basement membranes, tight interstitial spaces and endothelial cell layers are key steps in the metastatic cascade. Recent studies demonstrated that cell migration through three-dimensional environments that mimic the in vivo conditions significantly differs from their migration on two-dimensional surfaces. Here, we review recent technological advances made in the field of cancer research that provide more 'true to the source' experimental platforms and measurements for the study of cancer cell invasion and migration in three-dimensional environments. These include microfabrication, three-dimensional bioprinting and intravital imaging tools, along with force and stiffness measurements of cells and their environments. These techniques will enable new studies that better reflect the physiological environment found in vivo, thereby producing more robust results. The knowledge achieved through these studies will aid in the development of new treatment options with the potential to ultimately lighten the devastating cost cancer inflicts on patients and their families. This article is part of a discussion meeting issue 'Forces in cancer: interdisciplinary approaches in tumour mechanobiology'.

Manufacturing of Multi-drug Formulations with Customised Dose by Solvent Impregnation of Mesoporous Silica Tablets

The manufacture of personalised medicines where specific combinations of active pharmaceutical ingredients (APIs) and their dose within a tablet would be adjusted to the needs of individual patients, would require new manufacturing approaches compared to the established practice. In the case of low-dose formulations, the required precision of API content might not be achievable by traditional unit operations such as solid powder blending. The aim of the present work was to explore an alternative approach, based on the concept of pre-formulated placebo tablets containing mesoporous silica particles capable of absorbing APIs in the form of solutions, which can be precisely dosed at arbitrarily low quantities. The precision of the liquid dosing system has been validated; it was shown that the mechanical properties of the tablets were satisfactory even after multiple impregnation-drying cycles and that pharmacopoeia specifications on content uniformity could be met. Using model APIs, the spatial distribution of the API within the tablet after impregnation was investigated and shown to depend on the number and order of the impregnation-drying cycles. It was found that when an API was loaded to the tablet in a single step, a different dissolution profile was obtained compared to the same quantity dosed in multiple smaller steps. Overall, the approach of loading multiple API to a pre-formulated tablet at defined quantities using drop-on-demand liquid dosing was found to be feasible from the dose uniformity point of view. Further research should focus on potential API interactions and storage stability of tablets manufactured in this way.

Analytical aspects of printed oral dosage forms

Printing technologies, both 2D and 3D, have gained considerable interest during the last years for manufacturing of personalized dosage forms, tailored to each patient. Here we review the research work on 2D printing techniques, mainly inkjet printing, for manufacturing of film-based oral dosage forms. We describe the different printing techniques and give an overview of film-based oral dosage forms produced using them. The main part of the review focuses on the non-destructive analytical methods used for evaluation of qualitative aspects of printed dosage forms, e.g., solid-state properties, as well as for quantification of the active pharmaceutical ingredient (API) in the printed dosage forms, with an emphasis on spectroscopic methods. Finally, the authors share their view on the future of printed dosage forms.

Printing T3 and T4 oral drug combinations as a novel strategy for hypothyroidism

Hypothyroidism is a chronic and debilitating disease that is estimated to affect 3% of the general population. Clinical experience has highlighted the synergistic value of combining triiodothyronine (T₃) and thyroxine (T₄) for persistent or recurrent symptoms. However, thus far a platform that enables the simultaneous and independent dosing of more than one drug for oral administration has not been developed. Thermal inkjet (TIJ) 2D printing is a potential solution to enable the dual deposition of T₃ and T₄ onto orodispersible films (ODFs) for therapy personalisation. In this study, a two-cartridge TIJ printer was modified such that it could print separate solutions of T₃ and T₄. Dose adjustments were achieved by printing solutions adjacent to each other, enabling therapeutic T₃ (15-50 μg) and T₄ dosages (60-180 μg) to be successfully printed. Excellent linearity was observed between the theoretical and measured dose for both T₃ and T₄ (R² = 0.982 and 0.985, respectively) by changing the length of the print objective (Y-value). Rapid disintegration of the ODFs was achieved (<45 s). As such, this study for the first time demonstrates the ability to produce personalised dose combinations by TIJ printing T₃ and T₄ onto the same substrate for oral administration.

Valvejet Technology for the Production of a Personalised Fixed Dose Combination of Ramipril and Glimepiride: an Investigative Study on the Stability of Ramipril

PURPOSE

To use valvejet technology for printing a fixed dose combination of ramipril and glimepiride, and to investigate the stability profile of ramipril, which is susceptible to a range of processing and storage conditions.

METHODS

Inks of ramipril and glimepiride were formulated and printed on to HPMC film and the films were evaluated for the chemical and solid-state integrity of the APIs using HPLC and XRPD. The stability of the APIs in the inks and in the printed samples was investigated using Raman and NMR techniques.

RESULTS

The printed samples demonstrated excellent precision and accuracy in the doses of APIs deposited. Both drugs were chemically intact in the freshly printed samples and ramipril was found to be in its amorphous form. Ramipril in the printed samples has transformed into ramipril diketopiperazine when stored at 40°C with 75% RH, but remained stable when stored in a desiccator. Results from the stability study of ramipril ink show that the API has undergone degradation when stored both at room temperature and at 40°C but remained stable when stored in a refrigerator.

CONCLUSION

An FDC of ramipril and glimepiride was successfully printed using valvejet technology. The significance of inkjet printing in producing amorphous dosage forms from solution based inks and personalised dosage forms of drugs susceptible to processing conditions was demonstrated using ramipril. This study illustrates the significance of examining the stability of the APIs in the inks and the importance of appropriate storing of both the inks and printed samples.

3D bioprinting of functional tissue models for personalized drug screening and in vitro disease modeling

3D bioprinting is emerging as a promising technology for fabricating complex tissue constructs with tailored biological components and mechanical properties. Recent advances have enabled scientists to precisely position materials and cells to build functional tissue models for in vitro drug screening and disease modeling. This review presents state-of-the-art 3D bioprinting techniques and discusses the choice of cell source and biomaterials for building functional tissue models that can be used for personalized drug screening and disease modeling. In particular, we focus on 3D-bioprinted liver models, cardiac tissues, vascularized constructs, and cancer models for their promising applications in medical research, drug discovery, toxicology, and other pre-clinical studies.

In Vitro Evaluation of 2D-Printed Edible Films for the Buccal Delivery of Diclofenac Sodium

Printing technologies have recently emerged in the development of novel drug delivery systems toward personalized medicine, to improve the performance of formulations, existing bioavailability patterns, and patients' compliance. In the context of two-dimensional printing, this article presents the development of buccal films that are designed to efficiently deliver a class II compound (diclofenac sodium), according to the Biopharmaceutics Classification System (BCS), to the oral cavity. The preparation of drug-loaded inks was carried out based on solubility studies and evaluation of rheological properties, combining ethanol and propylene glycol as optimal solvents. Deposition of the drug was achieved by increasing the number of printing layers onto edible substrates, to produce formulations with dose variance. Thermal analysis, X-ray diffraction, and infrared spectroscopy were used to characterize the developed films. Drug loading and water uptake studies complemented the initial assessment of the films, and preliminary in vitro studies were conducted to further evaluate their performance. The in vitro release profiles were recorded in simulated saliva, presenting the complete release of the incorporated active in a period of 10 min. The effect of multiple layers on the overall performance of films was completed with in vitro permeation studies, revealing the correlation between the number of printed layers and the apparent permeability coefficient.