Mucosal drug delivery and 3D printing technologies: A focus on special patient populations

PVA-based formulations as a design-technology platform for orally disintegrating film matrices

In the majority of pharmaceutical applications, polymers are employed extensively in a diverse range of pharmaceutical products, serving as indispensable components of contemporary solid oral dosage forms. A comprehensive understanding of the properties of polymers and selection the appropriate methods of characterization is essential for the design and development of novel drug delivery systems and manufacturing processes. Orally disintegrating film (ODF) formulations are considered to be a potential substitute to traditional oral dosage forms and an alternative method of drug administration for children and uncooperative adult patients, including those with swallowing difficulties. A multitude of pharmaceutical formulations with varying mechanical and biopharmaceutical properties have emerged from the modification of the original polymeric bulk. Here we propose different formulation approaches, i.e. solvent casting (SC), 3D printing (3DP), electrospinning (ES), and lyophilization (LP) that enabled us to adjust the disintegration time and the release profile of poorly water soluble haloperidol (HAL, BCS class II) from PVA (polyvinyl alcohol) based polymer films while maintaining similar hydrogel composition. In this study, the solubility of haloperidol in aqueous solution was improved by the addition of lactic acid. The prepared films were evaluated for their morphology (SEM, micro-CT), physicochemical and biopharmaceutical properties. TMDSC, TGA and PXRD were employed for extensive thermal and structural analysis of fabricated materials and their stability. These results allowed us to establish correlations between preparation technology, structural characteristics and properties of PVA films and to adapt the suitable manufacturing technique of the ODFs to achieve appropriate HAL dissolution behaviour.

Cold Laser Sintering of Medicines: Toward Carbon Neutral Pharmaceutical Printing

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

Mucoadhesive film for oral delivery of vaccines for protection of the respiratory tract

The delivery of vaccines plays a pivotal role in influencing the strength and longevity of the immune response and controlling reactogenicity. Mucosal immunization, as compared to parenteral vaccination, could offer greater protection against respiratory infections while being less invasive. While oral vaccination has been presumed less effective and believed to target mainly the gastrointestinal tract, trans-buccal delivery using mucoadhesive films (MAF) may allow targeted delivery to the mucosa. Here we present an effective strategy for mucosal delivery of several vaccine platforms incorporated in MAF, including DNA plasmids, viral vectors, and lipid nanoparticles incorporating mRNA (mRNA/LNP). The mRNA/LNP vaccine formulation targeting SARS-CoV-2 as a proof of concept remained stable within MAF consisting of slowly releasing water-soluble polymers and an impermeable backing layer, facilitating enhanced penetration into the oral mucosa. This formulation elicited antibody and cellular responses comparable to the intramuscular injection, but also induced the production of mucosal IgAs, highlighting its efficacy, particularly for use as a booster vaccine and the potential advantage for protection against respiratory infections. The MAF vaccine preparation demonstrates significant advantages, such as efficient delivery, stability, and simple noninvasive administration with the potential to alleviate vaccine hesitancy.

Inkjet Printing of Pharmaceuticals

Inkjet printing (IJP) is an additive manufacturing process that selectively deposits ink materials, layer-by-layer, to create 3D objects or 2D patterns with precise control over their structure and composition. This technology has emerged as an attractive and versatile approach to address the ever-evolving demands of personalized medicine in the healthcare industry. Although originally developed for nonhealthcare applications, IJP harnesses the potential of pharma-inks, which are meticulously formulated inks containing drugs and pharmaceutical excipients. Delving into the formulation and components of pharma-inks, the key to precise and adaptable material deposition enabled by IJP is unraveled. The review extends its focus to substrate materials, including paper, films, foams, lenses, and 3D-printed materials, showcasing their diverse advantages, while exploring a wide spectrum of therapeutic applications. Additionally, the potential benefits of hardware and software improvements, along with artificial intelligence integration, are discussed to enhance IJP's precision and efficiency. Embracing these advancements, IJP holds immense potential to reshape traditional medicine manufacturing processes, ushering in an era of medical precision. However, further exploration and optimization are needed to fully utilize IJP's healthcare capabilities. As researchers push the boundaries of IJP, the vision of patient-specific treatment is on the horizon of becoming a tangible reality.

Design and evaluation of propranolol hydrochloride loaded thiolated Zein/PEO electrospun fibrous matrix for transmucosal drug delivery

Thiolated polymers have garnered wide attention from researchers on mucoadhesive drug delivery. This work explores the thiolation of zein protein using cysteine amino acid via the EDC crosslinker. The optimization of thiolation and purification have been done and confirmed using Ellman's assay and Raman spectra. The thiolated Zein/PEO polymer blend has been appraised for electrospinning to fabricate fibrous matrices. The extent of thiol modification augmented the mechanical properties and adhesion in rabbit intestinal mucosa. In vitro cytotoxicity evaluations such as direct contact assay, MTT assay, and live dead assay performed in RPMI 2650 cells corroborated the non-cytotoxicity of the fabricated matrices with and without propranolol hydrochloride (PL). Detailed drug release studies were conducted in PBS. Drug release in PBS followed the Korsmeyer Peppas model of release. On treating RPMI 2650 cells with the matrix, F-actin and adherens junctional proteins retained integrity, and consequently, drug permeation would proceed through the transcellular transport mechanism. Transepithelial electrical resistance (TEER) measurement of the RPMI 2650 cell monolayer also supported the transcellular transport mechanism. Ex vivo permeation study through porcine buccal mucosa showed 41.26 ± 0.56% PL permeation within 24 h of study. It validated the competence of the electrospun thiolated Zein/PEO matrix for transmucosal drug delivery.

Mucoadhesive 3D printed vaginal ovules to treat endometriosis and fibrotic uterine diseases

Gynaecological health is a neglected field of research that includes conditions such as endometriosis, uterine fibroids, infertility, viral and bacterial infections, and cancers. There is a clinical need to develop dosage forms for gynecological diseases that increase efficacy and reduce side effects and explore new materials with properties tailored to the vaginal mucosa and milieu. Here, we developed a 3D printed semisolid vaginal ovule containing pirfenidone, a repurposed drug candidate for endometriosis. Vaginal drug delivery allows direct targeting of the reproductive organs via the first uterine pass effect, but vaginal dosage forms can be challenging to self-administer and retain in situ for periods of more than 1-3 h. We show that a semisoft alginate-based vaginal suppository manufactured using semisolid extrusion additive manufacturing is superior to vaginal ovules made using standard excipients. The 3D-printed ovule showed a controlled release profile of pirfenidone in vitro in standard and biorelevant release tests, as well as better mucoadhesive properties ex vivo. An exposure time of 24 h of pirfenidone to a monolayer culture of an endometriotic epithelial cell line, 12Z, is necessary to reduce the cells' metabolic activity, which demonstrates the need for a sustained release formulation of pirfenidone. 3D printing allowed us to formulate mucoadhesive polymers into a semisolid ovule with controlled release of pirfenidone. This work enables further preclinical and clinical studies into vaginally administered pirfenidone to assess its efficacy as a repurposed endometriosis treatment.

Fabrication of 3D Printed Hollow Microneedles by Digital Light Processing for the Buccal Delivery of Actives

In the present study, two different microneedle devices were produced using digital light processing (DLP). These devices hold promise as drug delivery systems to the buccal tissue as they increase the permeability of actives with molecular weights between 600 and 4000 Da. The attached reservoirs were designed and printed along with the arrays as a whole device. Light microscopy was used to quality control the printability of the designs, confirming that the actual dimensions are in agreement with the digital design. Non-destructive volume imaging by means of microfocus computed tomography was employed for dimensional and defect characterization of the DLP-printed devices, demonstrating the actual volumes of the reservoirs and the malformations that occurred during printing. The penetration test and finite element analysis showed that the maximum stress experienced by the needles during the insertion process (10 N) was below their ultimate compressive strength (240-310 N). Permeation studies showed the increased permeability of three model drugs when delivered with the MN devices. Size-exclusion chromatography validated the stability of all the actives throughout the permeability tests. The safety of these printed devices for buccal administration was confirmed by histological evaluation and cell viability studies using the TR146 cell line, which indicated no toxic effects.

Combinatorial 3D printed dosage forms for a two-step and controlled drug release

Fused deposition modeling (FDM) and selective laser sintering (SLS) are two of the most employed additive manufacturing (AM) techniques within the pharmaceutical research field. Despite the numerous advantages of different AM methods, their respective drawbacks have yet to be fully addressed, and therefore combinatorial systems are starting to emerge. In the present study, hybrid systems comprising SLS inserts and a two-compartment FDM shell are developed to achieve controlled release of the model drug theophylline. Via the use of SLS a partial amorphization of the drug is demonstrated, which can be advantageous in the case of poorly soluble drugs, and it is shown that sintering parameters can regulate the dosage and release kinetics of the drug from the inserts. Furthermore, via different combinations of inserts within the FDM-printed shell, various drug release patterns, such as a two-step or prolonged release, can be achieved. The study serves as a proof of concept, highlighting the advantages of combining two AM techniques, both to overcome their respective shortcomings and to develop modular and highly tunable drug delivery devices.

Release Kinetics of Metronidazole from 3D Printed Silicone Scaffolds for Sustained Application to the Female Reproductive Tract

Sustained vaginal administration of antibiotics or probiotics has been proposed to improve treatment efficacy for bacterial vaginosis. 3D printing has shown promise for development of systems for local agent delivery. In contrast to oral ingestion, agent release kinetics can be fine-tuned by the 3D printing of specialized scaffold designs tailored for particular treatments while enhancing dosage effectiveness via localized sustained release. It has been challenging to establish scaffold properties as a function of fabrication parameters to obtain sustained release. In particular, the relationships between scaffold curing conditions, compressive strength, and drug release kinetics remain poorly understood. This study evaluates 3D printed scaffold formulation and feasibility to sustain the release of metronidazole, a commonly used antibiotic for BV. Cylindrical silicone scaffolds were printed and cured using three different conditions relevant to potential future incorporation of temperature-sensitive labile biologics. Compressive strength and drug release were monitored for 14d in simulated vaginal fluid to assess long-term effects of fabrication conditions on mechanical integrity and release kinetics. Scaffolds were mechanically evaluated to determine compressive and tensile strength, and elastic modulus. Release profiles were fitted to previous kinetic models to differentiate potential release mechanisms. The Higuchi, Korsmeyer-Peppas, and Peppas-Sahlin models best described the release, indicating similarity to release from insoluble or polymeric matrices. This study shows the feasibility of 3D printed silicone scaffolds to provide sustained metronidazole release over 14d, with compressive strength and drug release kinetics tuned by the fabrication parameters.

Recent trends of 3D printing based on starch-hydrocolloid in food, biomedicine and environment

People are exploring the potential application of 3D printing in food, biomedicine and environment, but it is urgent to find suitable bio-ink. Bio-ink compounded with starch and hydrocolloid can not only improve the rheology, structure and printability of starch-based edible bio-ink, but also endow it with other functional characteristics, so that it can be applied to food, biomedicine and even the environment, and meet the strategic needs of national health, green and sustainable development. In this paper, hydrocolloids are reviewed as potential means to regulate the physicochemical properties of starch, which endows it with good printability and presents excellent printing products. The specific applications of the bio-ink in the fields of food, biomedicine and environment in hypoglycemic, lipid-lowering, swallowable food, delivery, intelligent materials, and bio-sensor are also discussed. Then, the challenges and future development trends of realizing large-scale application are prospected. Proper physicochemical properties of starch-hydrocolloid are positively correlated with printability. The presentation of excellent printability has realized the application in different fields, not only satisfies most people, but also create benefits for some specific people. This review is expected to provide some theoretical guidance for the further development of 3D printing technology and its large-scale application.

Technological Aspects and Evaluation Methods for Polymer Matrices as Dental Drug Carriers

The development of polymer matrices as dental drug carriers takes into account the following technological aspects of the developed formulations: the composition and the technology used to manufacture them, which affect the properties of the carriers, as well as the testing methods for assessing their behavior at application sites. The first part of this paper characterizes the methods for fabricating dental drug carriers, i.e., the solvent-casting method (SCM), lyophilization method (LM), electrospinning (ES) and 3D printing (3DP), describing the selection of technological parameters and pointing out both the advantages of using the mentioned methods and their limitations. The second part of this paper describes testing methods to study the formulation properties, including their physical and chemical, pharmaceutical, biological and in vivo evaluation. Comprehensive in vitro evaluation of carrier properties permits optimization of formulation parameters to achieve prolonged retention time in the dynamic oral environment and is essential for explaining carrier behavior during clinical evaluation, consequently enabling the selection of the optimal formulation for oral application.

Gelatin methacrylate hydrogel with drug-loaded polymer microspheres as a new bioink for 3D bioprinting

3D bioprinted hydrogel constructs are advanced systems of a great drug delivery application potential. One of the bioinks that has recently gained a lot of attention is gelatin methacrylate (GelMA) hydrogel exhibiting specific properties, including UV cross-linking possibility. The present study aimed to develop a new bioink composed of GelMA and gelatin modified by addition of polymer (polycaprolactone or polyethersulfone) microspheres serving as bioactive substance carriers. The prepared microspheres suspension in GelMA/gelatin bioink was successfully bioprinted and subjected to various tests, which showed that the addition of microspheres and their type affects the physicochemical properties of the printouts. The hydrogel stability and structure was examined using scanning electron and optical microscopy, its thermal properties with differential scanning calorimetry and thermogravimetric analysis and its biocompatibility on HaCaT cells using viability assay and electron microscopy. Analyses also included tests of hydrogel equilibrium swelling ratio and release of marker substance. Subsequently, the matrices were loaded with ampicillin and the antibiotic release was validated by monitoring the antibacterial activity on Staphylococcus aureus and Escherichia coli. It was concluded that GelMA/gelatin bioink is a good and satisfying material for potential medical use. Depending on the polymer used, the addition of microspheres improves its structure, thermal and drug delivery properties.

Electrospun Mucoadhesive Zein/PVP Fibroporous Membrane for Transepithelial Delivery of Propranolol Hydrochloride

Mucoadhesive drug delivery systems have been extensively studied to effectively reduce the limitations of conventional drug delivery systems. Zein and polyvinyl pyrrolidone (PVP) are appraised for mucoadhesive properties. This study focuses on developing a mechanically stable zein/PVP electrospun membrane for propranolol hydrochloride (PL) transport. Fourier transform infrared, Raman spectra, and swelling studies gave evidence for PVP crosslinking, whereas circular dichroism spectroscopy revealed crosslinking of zein owing to the conformational change from α-helix to β-sheet. A 10 h thermal treatment of zein/PVP imparted 3.92 ± 0.13 MPa tensile strength to the matrix. Thermally crosslinked electrospun zein/PVP matrix showed 22.1 ± 0.1 g mm work of adhesion in porcine buccal mucosa tissue. Qualitative and quantitative evaluation of cytotoxicity in RPMI 2650 has been carried out. The in vitro drug release profile of PL from thermally crosslinked zein/PVP best fitted with the Korsmeyer-Peppas model. Immunostaining of β-catenin adherens junctional protein confirmed the absence of paracellular transport through the junctional opening. Still, drug permeation was observed through the porcine buccal mucosa, attributed to the transcellular transport of PL owing to its lipophilicity. The ex vivo permeation of PL through porcine buccal mucosa was also evaluated.

3D Printable Drug Delivery Systems: Next-generation Healthcare Technology and Regulatory Aspects

A revolutionary shift in healthcare has been sparked by the development of 3D printing, propelling us into an era replete with boundless opportunities for personalized DDS (Drug Delivery Systems). Precise control of the kinetics of drug release can be achieved through 3D printing, improving treatment efficacy and patient compliance. Additionally, 3D printing facilitates the co-administration of multiple drugs, simplifying treatment regimens. The technology offers rapid prototyping and manufacturing capabilities, reducing development timelines and costs. The seamless integration of advanced algorithms and artificial neural networks (ANN) augments the precision and efficacy of 3D printing, propelling us toward the forefront of personalized medicine. This comprehensive review delves into the regulatory frontiers governing 3D printable drug delivery systems, with an emphasis on adhering to rigorous safety protocols to ensure the well-being of patients by leveraging the latest advancements in 3D printing technologies powered by artificial intelligence. The paradigm promises superior therapeutic outcomes and optimized medication experiences and sets the stage for an immersive future within the Metaverse, wherein healthcare seamlessly converges with virtual environments to unlock unparalleled possibilities for personalized treatments.

Bioadhesive eutectogels supporting drug nanocrystals for long-acting delivery to mucosal tissues

Eutectogels (Egels) are an emerging class of soft ionic materials outperforming traditional temperature-intolerant hydrogels and costly ionogels. Due to their excellent elasticity, non-volatile nature, and adhesion properties, Egels are attracting a great deal of interest in the biomedical space. Herein, we report the first example of adhesive Egels loading drug nanocrystals (Egel-NCs) for controlled delivery to mucosal tissues. These soft materials were prepared using gelatin, glycerine, a deep eutectic solvent (DES) based on choline hydrochloride and glycerol, and nanocrystallised curcumin, a model drug with potent antimicrobial and anti-inflammatory activities. We first explored the impact of the biopolymer concentration on the viscoelastic and mechanical properties of the networks. Thanks to the dynamic interactions between gelatin and the DES, the Egel showed excellent stretchability and elasticity (up to ≈160%), reversible gel-sol phase transition at mild temperature (≈50 ​°C), 3D-printing ability, and good adhesion to mucin protein (stickiness ≈40 ​kPa). In vitro release profiles demonstrated the ability of the NCs-based Egel to deliver curcumin for up to four weeks and deposit significantly higher drug amounts in excised porcine mucosa compared to the control cohort. All in all, this study opens new prospects in designing soft adhesive materials for long-acting drug delivery and paves the way to explore novel eutectic systems with multiple therapeutic applications.

A method for evaluating drug penetration and absorption through isolated buccal mucosa with highly accuracy and reproducibility

The purpose of the project is to establish a standardized operation method of the in vitro permeability model to maximize mucosal integrity and viability. The model drug lidocaine permeability, 20 kDa fluorescein isothiocyanate-dextran, H&E staining, and mucosal viability were used as evaluation indicators. Firstly, the buccal mucosae of rats, rabbits, dogs, porcine, and humans were analyzed by H&E staining and morphometric analysis to compare the differences. Then, we studied a series of operation methods of isolated mucosa. The buccal mucosae were found to retain their integrity in Kreb's bicarbonate ringer solution at 4 °C for 36 h. Under the long-term storage method with program cooling, freezing at -80 °C, thawing at 37 °C, and using cryoprotectants of 20% glycerol and 20% trehalose, mucosal integrity and biological viability can be maintained for 21 days. The heat separation method was used to prepare a permeability model with a mucosal thickness of 500 μm, which was considered to be the optimal operation. In summary, this study provided an experimental basis for the selection and operation of in vitro penetration models, standardized the research process of isolated mucosa, and improved the accuracy of permeability studies.

Patches as Polymeric Systems for Improved Delivery of Topical Corticosteroids: Advances and Future Perspectives

Mucoadhesive polymer patches are a promising alternative for prolonged and controlled delivery of topical corticosteroids (CS) to improve their biopharmaceutical properties (mainly increasing local bioavailability and reducing systemic toxicity). The main biopharmaceutical advantages of patches compared to traditional oral dosage forms are their excellent bioadhesive properties and their increased drug residence time, modified and unidirectional drug release, improved local bioavailability and safety profile, additional pain receptor protection, and patient friendliness. This review describes the main approaches that can be used for the pharmaceutical R&D of oromucosal patches with improved physicochemical, mechanical, and pharmacological properties. The review mainly focuses on ways to increase the bioadhesion of oromucosal patches and to modify drug release, as well as ways to improve local bioavailability and safety by developing unidirectional -release poly-layer patches. Various techniques for obtaining patches and their influence on the structure and properties of the resulting dosage forms are also presented.

Design and Prototype Fabrication of a Cost-Effective Microneedle Drug Delivery Apparatus Using Fused Filament Fabrication, Liquid Crystal Display and Semi-Solid Extrusion 3D Printing Technologies

The current study describes the design of a cost-effective drug delivery apparatus that can be manufactured, assembled, and utilized as easily and quickly as possible, minimizing the time and expense of the supply chain. This apparatus could become a realistic alternative method of providing a vaccine or drug in harsh circumstances, including humanitarian disasters or a lack of medical and nursing staff, conditions that are frequently observed in developing countries. Simultaneously, with the use of microneedles (MNs), the apparatus can benefit from the numerous advantages offered by them during administration. The hollow microneedles in particular are internally perforated and are capable of delivering the active substance to the skin. The apparatus was designed with appropriate details in computer aided design software, and various 3D printing technologies were utilized in order to fabricate the prototype. The parts that required minimum accuracy, such as the main body of the apparatus, were fabricated with fused filament fabrication. The internal parts and the hollow microneedles were fabricated with liquid crystal display, and the substance for the drug loading carrier, which was an alginate gel cylinder, was fabricated with semi-solid extrusion 3D printing.

Fabrication and Preliminary In Vitro Evaluation of 3D-Printed Alginate Films with Cannabidiol (CBD) and Cannabigerol (CBG) Nanoparticles for Potential Wound-Healing Applications

In this study, drug carrier nanoparticles comprised of Pluronic-F127 and cannabidiol (CBD) or cannabigerol (CBG) were developed, and their wound healing action was studied. They were further incorporated in 3D printed films based on sodium alginate. The prepared films were characterized morphologically and physicochemically and used to evaluate the drug release profiles of the nanoparticles. Additional studies on their water loss rate, water retention capacity, and 3D-printing shape fidelity were performed. Nanoparticles were characterized physicochemically and for their drug loading performance. They were further assessed for their cytotoxicity (MTT Assay) and wound healing action (Cell Scratch Assay). The in vitro wound-healing study showed that the nanoparticles successfully enhanced wound healing in the first 6 h of application, but in the following 6 h they had an adverse effect. MTT assay studies revealed that in the first 24 h, a concentration of 0.1 mg/mL nanoparticles resulted in satisfactory cell viability, whereas CBG nanoparticles were safe even at 48 h. However, in higher concentrations and after a threshold of 24 h, the cell viability was significantly decreased. The results also presented mono-disperse nano-sized particles with diameters smaller than 200 nm with excellent release profiles and enhanced thermal stability. Their entrapment efficiency and drug loading properties were higher than 97%. The release profiles of the active pharmaceutical ingredients from the films revealed a complete release within 24 h. The fabricated 3D-printed films hold promise for wound healing applications; however, more studies are needed to further elucidate their mechanism of action.

Development of a Mucoadhesive Vehicle Based on Lyophilized Liposomes for Drug Delivery through the Sublingual Mucosa

A pharmaceutical vehicle based on lyophilized liposomes is proposed for the buccal administration of drugs aimed at systemic delivery through the sublingual mucosa. Liposomes made of egg phosphatidylcholine and cholesterol (7/3 molar ratio) were prepared and lyophilized in the presence of different additive mixtures with mucoadhesive and taste-masking properties. Palatability was assayed on healthy volunteers. The lyophilization cycle was optimized, and the lyophilized product was compressed to obtain round and capsule-shaped tables that were evaluated in healthy volunteers. Tablets were also assayed regarding weight and thickness uniformities, swelling index and liposome release. The results proved that lyophilized liposomes in unidirectional round tablets have palatability, small size, comfortability and buccal retention adequate for sublingual administration. In contact with water fluids, the tablets swelled, and rehydrated liposomes were released at a slower rate than permeation efficiency determined using a biomimetic membrane. Permeability efficiency values of 0.72 ± 0.34 µg/cm²/min and 4.18 ± 0.95 µg/cm²/min were obtained for the liposomes with and without additives, respectively. Altogether, the results point to the vehicle proposed as a liposomal formulation suitable for systemic drug delivery through the sublingual mucosa.

Drug-loaded mesoporous silica on carboxymethyl cellulose hydrogel: Development of innovative 3D printed hydrophilic films

3D printing has been explored as an emerging technology for the development of versatile and printable materials for drug delivery. However, the alliance of 3D printing and nanomaterials has, to date, been little explored in pharmaceutics. Herein, a mesoporous silica with nanostructured pores, SBA-15, was used as a drug carrier for triamcinolone acetonide, a hydrophobic drug, with the aim of incorporating the drug formulation in a hydrophilic printable ink. The adsorption of the drug in the SBA-15 pores was confirmed by the decrease in its surface area and pore volume, along with an increase in the apparent aqueous solubility of triamcinolone acetonide, as shown by in vitro release studies. Thereafter, a hydrophilic ink composed of carboxymethyl cellulose containing drug-loaded SBA-15 was formulated and 3D printed as hydrophilic polymeric film using the semisolid extrusion technique (SSE). The 3D printed films showed complete drug release after 12 h, and the presence of the triamcinolone acetonide-loaded SBA-15 improved their in vitro mucoadhesion, suggesting their promising application in oral mucosa treatments. Besides representing an innovative platform to develop water-based mucoadhesive formulations containing a hydrophobic drug, this is the first report proposing the development of SSE 3D printed nanomedicines containing drug-loaded mesoporous silica.

The Advent of a New Era in Digital Healthcare: A Role for 3D Printing Technologies in Drug Manufacturing?

The technological revolution has physically affected all manufacturing domains, at the gateway of the fourth industrial revolution. Three-dimensional (3D) printing has already shown its potential in this new reality, exhibiting remarkable applications in the production of drug delivery systems. As part of this concept, personalization of the dosage form by means of individualized drug dose or improved formulation functionalities has concentrated global research efforts. Beyond the manufacturing level, significant parameters must be considered to promote the real-time manufacturing of pharmaceutical products in distributed areas. The majority of current research activities is focused on formulating 3D-printed drug delivery systems while showcasing different scenarios of installing 3D printers in patients' houses, hospitals, and community pharmacies, as well as in pharmaceutical industries. Such research presents an array of parameters that must be considered to integrate 3D printing in a future healthcare system, with special focus on regulatory issues, drug shortages, quality assurance of the product, and acceptability of these scenarios by healthcare professionals and public parties. The objective of this review is to critically present the spectrum of possible scenarios of 3D printing implementation in future healthcare and to discuss the inevitable issues that must be addressed.

A new trend of using poly(vinyl alcohol) in 3D and 4D printing technologies: Process and applications

Recently, 3D/4D printing technologies have been the researchers' interest, and they are getting improved more important. They are applicable in various fields like medical fields, pharmaceutics, construction, tissue engineering, dentistry, water treatment, etc. These technologies overcame the difficulty of the conventional methods in producing complicated structures. They can be fed by different materials such as nanomaterials, smart polymers, responsive polymers, metamaterials, synthetic polymers, natural polymers, and so forth. One of the smart and stimuli-responsive polymers is poly(vinyl alcohol) (PVA). In addition to numerous applications of PVA like medicine, environmental fields, etc., researchers are showing a tendency to use PVA in 3D/4D printing technologies. The main reasons for PVA's increased interest in 3D/4D printing technologies are suitable flowability, stimuli-responsivity, extrudability, biocompatibility, biodegradability, cost-effectiveness, and other features. This review aims to introduce the 3D/4D printing technologies' knowledge and then the applications of PVA as a feed in these novel technologies.

Advancing pharmacy and healthcare with virtual digital technologies

Digitalisation of the healthcare sector promises to revolutionise patient healthcare globally. From the different technologies, virtual tools including artificial intelligence, blockchain, virtual, and augmented reality, to name but a few, are providing significant benefits to patients and the pharmaceutical sector alike, ranging from improving access to clinicians and medicines, as well as improving real-time diagnoses and treatments. Indeed, it is envisioned that such technologies will communicate together in real-time, as well as with their physical counterparts, to create a large-scale, cyber healthcare system. Despite the significant benefits that virtual-based digital health technologies can bring to patient care, a number of challenges still remain, ranging from data security to acceptance within the healthcare sector. This review provides a timely account of the benefits and challenges of virtual health interventions, as well an outlook on how such technologies can be transitioned from research-focused towards real-world healthcare and pharmaceutical applications to transform treatment pathways for patients worldwide.

Machine Learning and Machine Vision Accelerate 3D Printed Orodispersible Film Development

Orodispersible films (ODFs) are an attractive delivery system for a myriad of clinical applications and possess both large economical and clinical rewards. However, the manufacturing of ODFs does not adhere to contemporary paradigms of personalised, on-demand medicine, nor sustainable manufacturing. To address these shortcomings, both three-dimensional (3D) printing and machine learning (ML) were employed to provide on-demand manufacturing and quality control checks of ODFs. Direct ink writing (DIW) was able to fabricate complex ODF shapes, with thicknesses of less than 100 µm. ML algorithms were explored to classify the ODFs according to their active ingredient, by using their near-infrared (NIR) spectrums. A supervised model of linear discriminant analysis was found to provide 100% accuracy in classifying ODFs. A subsequent partial least square algorithm was applied to verify the dose, where a coefficient of determination of 0.96, 0.99 and 0.98 was obtained for ODFs of paracetamol, caffeine, and theophylline, respectively. Therefore, it was concluded that the combination of 3D printing, NIR and ML can result in a rapid production and verification of ODFs. Additionally, a machine vision tool was used to automate the in vitro testing. These collective digital technologies demonstrate the potential to automate the ODF workflow.

Smartphone-enabled 3D printing of medicines

3D printing is a manufacturing technique that is transforming numerous industrial sectors, particularly where it is key tool in the development and fabrication of medicinees that are personalised to the individual needs of patients. Most 3D printers are relatively large, require trained operators and must be located in a pharmaceutical setting to manufacture dosage forms. In order to realise fully the potential of point-of-care manufacturing of medicines, portable printers that are easy to operate are required. Here, we report the development of a 3D printer that operates using a mobile smartphone. The printer, operating on stereolithographic principles, uses the light from the smartphone's screen to photopolymerise liquid resins and create solid structures. The shape of the printed dosage form is determined using a custom app on the smartphone. Warfarin-loaded Printlets (3D printed tablets) of various sizes and patient-centred shapes (caplet, triangle, diamond, square, pentagon, torus, and gyroid lattices) were successfully printed to a high resolution and with excellent dimensional precision using different photosensitive resins. The drug was present in an amorphous form, and the Printlets displayed sustained release characterises. The promising proof-of-concept results support the future potential of this compact, user-friendly and interconnected smartphone-based system for point-of-care manufacturing of personalised medications.

Modular design principle based on compartmental drug delivery systems

The current manufacturing solutions for oral solid dosage forms are fundamentally based on technologies from the 19th century. This approach is well suited for mass production of one-size-fits-all products; however, it does not allow for a straight-forward personalization and mass customization of the pharmaceutical end-product. In order to provide better therapies to the patients, a need for innovative manufacturing concepts and product design principles has been rising. Additive manufacturing opens up a possibility for compartmentalization of drug products, including design of spatially separated multidrug and functional excipient compartments. This compartmentalized solution can be further expanded to modular design thinking. Modular design is referring to combination of building blocks containing a given amount of drug compound(s) and related functional excipients into a larger final product. Implementation of modular design principles is paving the way for implementing the emerging personalization potential within health sciences by designing compartmental and reactive product structures that can be manufactured based on the individual needs of each patient. This review will introduce the existing compartmentalized product design principles and discuss the integration of these into edible electronics allowing for innovative control of drug release.