Drug Incorporation into Polymer Filament Using Simple Soaking Method for Tablet Preparation Using Fused Deposition Modeling

Use of Winemaking By-Products for the Functionalization of Polylactic Acid for Biomedical Applications

The addition of naturally active compounds to implantable polymers is an efficient strategy against inflammation issues that might lead to rejection, while promoting controlled re-endothelialization of the tissues. This work proposes the use of winemaking by-products with high active properties of biomedical interest to obtain bioactive PLA by using supercritical technologies. First, two red grape pomace extracts, obtained by high-pressure extraction with supercritical CO₂ and cosolvents (either ethanol or water-ethanol), have been studied. Second, two impregnation methods have been studied with both extracts, traditional supercritical CO₂-assisted impregnation (SSI) and a novel pressurized soaking method (PSI). The amount of extract impregnated as well as the bioactivity levels achieved-i.e., antioxidant, antimicrobial, and anti-inflammatory properties- have been determined for each extract and impregnation method at different pressure and temperature conditions. Both extracts obtained had good antioxidant, anti-inflammatory, and antibacterial capacities, especially the hydroethanolic one (0.50 ± 0.03 mg TE/g versus 0.24 ± 0.03 mg TE/g, respectively). Regarding impregnated filaments, impregnation loadings depended especially on the extract and P/T conditions, providing up to 8% (extract mass/polymer mass) of impregnation. The antioxidant capacity increased noteworthily by using the ethanolic extract by PSI, with values near 100 µg TE/g PLA.

A Review on Physicochemical Properties of Polymers Used as Filaments in 3D-Printed Tablets

Three-dimensional (3D) printing technology has presently been explored widely in the field of pharmaceutical research to produce various conventional as well as novel dosage forms such as tablets, capsules, oral films, pellets, subcutaneous implants, scaffolds, and vaginal rings. The use of this innovative method is a good choice for its advanced technologies and the ability to make tailored medicine specifically for individual patient. There are many 3D printing systems that are used to print tablets, implants, and vaginal rings. Among the available systems, the fused deposition modeling (FDM) is widely utilized. The FDM has been regarded as the best choice of printer as it shows high potential in the production of tablets as a unit dose in 3D printing medicine manufacturing. In order to design a 3D-printed tablet or other dosage forms, the physicochemical properties of polymers play a vital role. One should have proper knowledge about the polymer's properties so that one can select appropriate polymers in order to design 3D-printed dosage form. This review highlighted the various physicochemical properties of polymers that are currently used as filaments in 3D printing. In this manuscript, the authors also discussed various systems that are currently adopted in the 3D printing.

Processability of mesoporous materials in fused deposition modeling for drug delivery of a model thermolabile drug

The incorporation of drug-loaded mesoporous materials in dosage forms prepared with fused deposition modeling (FDM) has shown the potential to solve challenges relating to additive manufacturing techniques, such as the stability of poorly-soluble drugs in the amorphous state. However, the addition of these non-melting mesoporous materials significantly affects the mechanical properties of the filament used in FDM, which in turn affects the printability of the feedstock material. Therefore, in this study a full-factorial experimental design was utilized to investigate different processing parameters of the hot melt extrusion process, their effect on various mechanical properties and the potential correlation with the filaments' printability. The thermolabile, poorly-soluble drug ibuprofen was utilized as a model drug to assess the potential of two mesoporous materials, Mesoporous Magnesium Carbonate (MMC) and a silica-based material (MCM-41), to thermally protect the loaded drug. Factorial and principal components analysis displayed a correlation between non-printable MCM-41 filaments and their mechanical properties where printable filaments had a maximum stress >7.5 MPa and a Young's modulus >83 MPa. For MMC samples there was no clear correlation, which was in large part attributed to the filaments' inconsistencies and imperfections. Finally, both mesoporous materials displayed a thermal protective feature, as the decomposition due to the thermal degradation of a significant portion of the thermolabile drug was shifted to higher temperatures post-loading. This highlights the potential capability of such a system to be implemented for thermosensitive drugs in FDM applications.

Additive Manufacturing Strategies for Personalized Drug Delivery Systems and Medical Devices: Fused Filament Fabrication and Semi Solid Extrusion

Novel additive manufacturing (AM) techniques and particularly 3D printing (3DP) have achieved a decade of success in pharmaceutical and biomedical fields. Highly innovative personalized therapeutical solutions may be designed and manufactured through a layer-by-layer approach starting from a digital model realized according to the needs of a specific patient or a patient group. The combination of patient-tailored drug dose, dosage, or diagnostic form (shape and size) and drug release adjustment has the potential to ensure the optimal patient therapy. Among the different 3D printing techniques, extrusion-based technologies, such as fused filament fabrication (FFF) and semi solid extrusion (SSE), are the most investigated for their high versatility, precision, feasibility, and cheapness. This review provides an overview on different 3DP techniques to produce personalized drug delivery systems and medical devices, highlighting, for each method, the critical printing process parameters, the main starting materials, as well as advantages and limitations. Furthermore, the recent developments of fused filament fabrication and semi solid extrusion 3DP are discussed. In this regard, the current state of the art, based on a detailed literature survey of the different 3D products printed via extrusion-based techniques, envisioning future directions in the clinical applications and diffusion of such systems, is summarized.

Coupling of Fused Deposition Modeling and Inkjet Printing to Produce Drug Loaded 3D Printed Tablets

In the current study, we have coupled Fused Deposition Modelling (FDM) for the fabrication of plain polyvinyl alcohol (PVA) tablets followed by dispensing of minoxidil ethanolic solutions using inkjet printing. The use of a drop-on-solid printing approach facilitates an accurate and reproducible process while it controls the deposition of the drug amounts. For the purpose of the study, the effect of the solvent was investigated and minoxidil ink solutions of ethanol 70% v/v (P70) or absolute ethanol (P100) were applied on the plain PVA tablets. Physicochemical characterization showed that solvent miscibility with the polymer substrate plays a key role and can lead to the formation of drug crystals on the surface or drug absorption in the polymer matrix. The produced minoxidil tablets showed sustained release profiles or initial bursts strongly affected by the solvent grade used for dispensing the required dose on drug loaded 3D printed tablets. This paradigm demonstrates that the coupling of FDM and inkjet printing technologies could be used for rapid development of personalized dosage forms.

The potential of natural products use in fused deposition modeling 3D printing of pharmaceutical dosage forms

In recent years, the interest in 3D printing of medicines has increased due to many advantages of this technology, such as flexibility of the dose and dosage form of the printed product. Fused deposition modeling (FDM) is one of the most popular 3D printing technologies in the pharmaceutical field, due to its low cost and simplicity. The subject of this review is the potential use of natural products as biodegradable and biocompatible materials with good safety profiles in FDM 3D printing of pharmaceuticals. Natural products such as alginate, chitosan and starch have already been employed as excipients in FDM 3D printed pharmaceutical dosage forms, while others like shellac and zein show the potential, but haven't yet been part of 3D printed pharmaceutical formulations. These excipients have different roles in the formulation of filaments for FDM 3D printing, for example as fillers, matrix carriers or drug-release modifiers. In addition, the possibility of incorporating active pharmaceutical ingredients of natural origin in filaments for FDM 3D printing was reviewed. High printing temperatures limit the use of natural products in FDM 3D printing. However, adequate selection of thermoplastic material and printing parameters can widen the use of natural products in FDM 3D printing of pharmaceutical dosage forms.

Octacalcium phosphate: Innovative vehicle for the local biologically active substance delivery in bone regeneration

Disadvantages of conventional drug delivery systems (DDS), such as systemic circulation, interaction with physiochemical factors, reduced bioavailability, and insufficient drug concentration at bone defect site, have underlined the importance of developing efficacious local drug delivery systems. Octacalcium phosphate (OCP) is presumed to be the precursor of biologically formed apatite, owing to its similarity to hydroxyapatite (HAp) and readiness to convert to it. Specific crystal structure of OCP is constructed of compiled apatite layers and water layers, which make possible the incorporation of various ions in its structure, making it feasible to alter the overall effect OCP has in the system. Next to that intrinsic property, characteristics as high solubility, biodegradability and osteoconductivity have made it indispensable to tailor OCP as a carrier material. In this review, we present the main characteristics and progress done on utilizing OCP as an innovative vehicle and provide suggestions for possible research pathways and advantages for local drug delivery in bone tissue engineering. STATEMENT OF SIGNIFICANCE: Octacalcium phosphate (OCP), being a precursor to biologically formed apatite, has many assets when compared to other calcium phosphates. Owing to its highly pertinent structure, it is being used as a vehicle for biologically active substances or ions for bone regeneration. However, orchestrating drug delivery systems with OCP, in order to achieve the best possible outcome, is still a pioneering concept, and the all-encompassing data is still scarce. Although several articles have been published on this matter, to this date there is no systematic overview pointing out the benefits that OCP can bring in the field of drug delivery. Here we offer a comprehensive overview, starting from the OCP synthesis to its structure, morphology, and the biological significance OCP has.

An updated review on application of 3D printing in fabricating pharmaceutical dosage forms

The concept of "one size fits all" followed by the conventional healthcare system has drawbacks in providing precise pharmacotherapy due to variation in the pharmacokinetics of different patients leading to serious consequences such as side effects. In this regard, digital-based three-dimensional printing (3DP), which refers to fabricating 3D printed pharmaceutical dosage forms with variable geometry in a layer-by-layer fashion, has become one of the most powerful and innovative tools in fabricating "personalized medicine" to cater to the need of therapeutic benefits for patients to the maximum extent. This is achieved due to the tremendous potential of 3DP in tailoring various drug delivery systems (DDS) in terms of size, shape, drug loading, and drug release. In addition, 3DP has a huge impact on special populations including pediatrics, geriatrics, and pregnant women with unique or frequently changing medical needs. The areas covered in the present article are as follows: (i) the difference between traditional and 3DP manufacturing tool, (ii) the basic processing steps involved in 3DP, (iii) common 3DP methods with their pros and cons, (iv) various DDS fabricated by 3DP till date with discussing few research studies in each class of DDS, (v) the drug loading principles into 3D printed dosage forms, and (vi) regulatory compliance.

Design and characterization of 3D printed, neomycin-eluting poly-L-lactide mats for wound-healing applications

This study evaluates the suitability of 3D printed biodegradable mats to load and deliver the topical antibiotic, neomycin, for up to 3 weeks in vitro. A 3D printer equipped with a hot melt extruder was used to print bandage-like wound coverings with porous sizes appropriate for cellular attachment and viability. The semicrystalline polyester, poly-l-lactic acid (PLLA) was used as the base polymer, coated (post-printing) with polyethylene glycols (PEGs) of MWs 400 Da, 6 kDa, or 20 kDa to enable manipulation of physicochemical and biological properties to suit intended applications. The mats were further loaded with a topical antibiotic (neomycin sulfate), and cumulative drug-release monitored for 3 weeks in vitro. Microscopic imaging as well as Scanning Electron Microscopy (SEM) studies showed pore dimensions of 100 × 400 µm. These pore dimensions were achieved without compromising mechanical strength; because of the "tough" individual fibers constituting the mat (Young's Moduli of 50 ± 20 MPa and Elastic Elongation of 10 ± 5%). The in vitro dissolution study showed first-order release kinetics for neomycin during the first 20 h, followed by diffusion-controlled (Fickian) release for the remaining duration of the study. The release of neomycin suggested that the ability to load neomycin on to PLLA mats increases threefold, as the MW of the applied PEG coating is lowered from 20 kDa to 400 Da. Overall, this study demonstrates a successful approach to using a 3D printer to prepare porous degradable mats for antibiotic delivery with potential applications to dermal regeneration and tissue engineering. Illustration of the process used to create and characterize 3D printed PLLA mats.

Investigations of process parameters during dissolution studies of drug loaded 3D printed tablets

The present research paper attempts to study the effect of different process parameters on the dissolution rate during 3D printed tablets. Three-dimensional printing has the potential of serving tailored made tablets to cater personalized drug delivery systems. Fluorescein loaded PVA filaments through impregnation route was used to fabricate tablets based on Taguchi based design of experimentation using Fused Deposition Modelling (FDM). The effect of print speed, infill percentage and layer thickness were analyzed to study the effect on rate of dissolution. Infill percentage followed by print speed were found to be critical parameters affecting dissolution rate. The data analysis provided an insight into the study of interaction among different 3D printing parameters to develop an empirical relation for percentage release of the drug in human body.

3D printing technology as innovative solutions for biomedical applications

3D printing was once predicted to be the third industrial revolution. Today, the use of 3D printing is found across almost all industries. This article discusses the latest 3D printing applications in the biomedical industry.

3D Printing of Tunable Zero-Order Release Printlets

Zero-order release formulations are designed to release a drug at a constant rate over a prolonged time, thus reducing systemic side effects and improving patience adherence to the therapy. Such formulations are traditionally complex to manufacture, requiring multiple steps. In this work, fused deposition modeling (FDM) 3D printing was explored to prepare on-demand printlets (3D printed tablets). The design includes a prolonged release core surrounded by an insoluble shell able to provide zero-order release profiles. The effect of drug loading (10, 25, and 40% w/w paracetamol) on the mechanical and physical properties of the hot melt extruded filaments and 3D printed formulations was evaluated. Two different shell 3D designs (6 mm and 8 mm diameter apertures) together with three different core infills (100, 50, and 25%) were prepared. The formulations showed a range of zero-order release profiles spanning 16 to 48 h. The work has shown that with simple formulation design modifications, it is possible to print extended release formulations with tunable, zero-order release kinetics. Moreover, by using different infill percentages, the dose contained in the printlet can be infinitely adjusted, providing an additive manufacturing route for personalizing medicines to a patient.

Production of Drug Delivery Systems Using Fused Filament Fabrication: A Systematic Review

Fused filament fabrication (FFF) 3D printing technology is widely used in many fields. For almost a decade, medical researchers have been exploring the potential use of this technology for improving the healthcare sector. Advances in personalized medicine have been more achievable due to the applicability of producing drug delivery devices, which are explicitly designed based on patients’ needs. For the production of these devices, a filament—which is the feedstock for the FFF 3D printer—consists of a carrier polymer (or polymers) and a loaded active pharmaceutical ingredient (API). This systematic review of the literature investigates the most widely used approaches for producing drug-loaded filaments. It also focusses on several factors, such as the polymeric carrier and the drug, loading capacity and homogeneity, processing conditions, and the intended applications. This review concludes that the filament preparation method has a significant effect on both the drug homogeneity within the polymeric carrier and drug loading efficiency.