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Journal ArticleDOI: 10.1016/J.IJPHARM.2021.120452

Gelatine-based drug-eluting bandage contact lenses: Effect of PEGDA concentration and manufacturing technique.

04 Mar 2021-International Journal of Pharmaceutics (Elsevier)-Vol. 599, pp 120452-120452
Abstract: Drug-eluting bandage contact lenses (BCLs) have been widely studied as an alternative to eye drops due to their ability to increase the drug residence time and bioavailability as well as improve patient compliance. While silicone hydrogel polymers are commonly used in drug-eluting BCLs due to their transparency, mechanical properties and high oxygen permeability, gelatine hydrogels are also clear, flexible and have high oxygen permeability and may therefore be suitable contact lens materials. Moreover, the rheological properties of gelatine hydrogels allow their use as inks in extrusion-based 3D printers, therefore opening the door to a wide range of applications. Drug-loaded gelatine methacryloyl (GelMA) BCLs with different concentrations of poly (ethylene glycol) diacrylate (PEGDA) were prepared using solvent casting and 3D printing. The prepared lenses were characterised for their swelling ratio, in vitro degradation, and drug release properties. The results showed that the incorporation of 10% PEGDA improved the lenses’ resistance to handling and protected them during degradation testing, reduced the swelling ratio and prolonged the release of dexamethasone (DEX). Both techniques were deemed suitable to use in the manufacturing of drug-eluting BCLs noting that the optimal formulation may vary according to the preparation technique utilised.

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Topics: Contact lens (54%), Self-healing hydrogels (52%)

5 results found

Journal ArticleDOI: 10.1016/J.ADDR.2021.113858
Abstract: In the last decade, additive manufacturing (AM) technologies have revolutionized how healthcare provision is envisioned. The rapid evolution of these technologies has already created a momentum in the effort to address unmet personalized needs in large patient groups, especially those belonging to sensitive subgroup populations (e.g., paediatric, geriatric, visually impaired). At the same time, AM technologies have become a salient ally to overcome defined health challenges in drug formulation development by addressing not only the requirement of personalized therapy, but also problems related to lowering non-specific drug distribution and the risk of adverse reactions, enhancing drug absorption and bioavailability, as well as ease of administration and patient compliance. To this end, mucoadhesive drug delivery systems fabricated with the support of AM technologies provide competitive advantages over conventional dosage forms, aiming to entice innovation in drug formulation with special focus on sensitive patient populations.

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4 Citations

Open accessJournal ArticleDOI: 10.3390/PHARMACEUTICS13091421
Xiaoyan Xu1, Sahar Awwad1, Luis Diaz-Gomez2, Carmen Alvarez-Lorenzo2  +5 moreInstitutions (2)
08 Sep 2021-Pharmaceutics
Abstract: Dry eye disease is a common ocular disorder that is characterised by tear deficiency or excessive tear evaporation. Current treatment involves the use of eye drops; however, therapeutic efficacy is limited because of poor ocular bioavailability of topically applied formulations. In this study, digital light processing (DLP) 3D printing was employed to develop dexamethasone-loaded punctal plugs. Punctal plugs with different drug loadings were fabricated using polyethylene glycol diacrylate (PEGDA) and polyethylene glycol 400 (PEG 400) to create a semi-interpenetrating network (semi-IPN). Drug-loaded punctal plugs were characterised in terms of physical characteristics (XRD and DSC), potential drug-photopolymer interactions (FTIR), drug release profile, and cytocompatibility. In vitro release kinetics of the punctal plugs were evaluated using an in-house flow rig model that mimics the subconjunctival space. The results showed sustained release of dexamethasone for up to 7 days from punctal plugs made with 20% w/w PEG 400 and 80% w/w PEGDA, while punctal plugs made with 100% PEGDA exhibited prolonged releases for more than 21 days. Herein, our study demonstrates that DLP 3D printing represents a potential manufacturing platform for fabricating personalised drug-loaded punctal plugs with extended release characteristics for ocular administration.

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Topics: Punctal plug (60%)

2 Citations

Open accessJournal ArticleDOI: 10.3390/POLYM13183107
Yi-Ting Lin1, Ming-You Shie2, Yen-Hong Lin2, Chia-Che Ho3  +2 moreInstitutions (3)
15 Sep 2021-Polymers
Abstract: Pulp regeneration is one of the most successful areas in the field of tissue regeneration, despite its current limitations. The biocompatibility of endodontic biomaterials is essential in securing the oral microenvironment and supporting pulp tissue regeneration. Therefore, the objective of this study was to investigate the new light-curable calcium silicate (CS)-containing polyethylene glycol diacrylate (PEGDA) biocomposites’ regulation of human dental pulp stem cells (hDPSCs) in odontogenic-related regeneration. The CS-containing PEGDA (0 to 30 wt%) biocomposites are applied to endodontics materials to promote their mechanical, bioactive, and biological properties. Firstly, X-ray diffraction and Fourier-transform infrared spectroscopy showed that the incorporation of CS increased the number of covalent bonds in the PEGDA. The diameter tension strength of the CS-containing PEGDA composite was significantly higher than that of normal PEGDA, and a different microstructure was detected on the surface. Samples were analyzed for their surface characteristics and Ca/Si ion-release profiles after soaking in simulated body fluid for different periods of time. The CS30 group presented better hDPSC adhesion and proliferation in comparison with CS0. Higher values of odontogenic-related biomarkers were found in hDPSCs on CS30. Altogether, these results prove the potential of light-curable CS-containing PEGDA composites as part of a ‘point-of-care’ strategy for application in odontogenesis-related regeneration.

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Topics: Biocompatibility (50%)

1 Citations

Open accessJournal ArticleDOI: 10.1007/S40123-021-00379-6
Abstract: Three-dimensional printing enables precise modeling of anatomical structures and has been employed in a broad range of applications across medicine. Its earliest use in eye care included orbital models for training and surgical planning, which have subsequently enabled the design of custom-fit prostheses in oculoplastic surgery. It has evolved to include the production of surgical instruments, diagnostic tools, spectacles, and devices for delivery of drug and radiation therapy. During the COVID-19 pandemic, increased demand for personal protective equipment and supply chain shortages inspired many institutions to 3D-print their own eye protection. Cataract surgery, the most common procedure performed worldwide, may someday make use of custom-printed intraocular lenses. Perhaps its most alluring potential resides in the possibility of printing tissues at a cellular level to address unmet needs in the world of corneal and retinal diseases. Early models toward this end have shown promise for engineering tissues which, while not quite ready for transplantation, can serve as a useful model for in vitro disease and therapeutic research. As more institutions incorporate in-house or outsourced 3D printing for research models and clinical care, ethical and regulatory concerns will become a greater consideration. This report highlights the uses of 3D printing in eye care by subspecialty and clinical modality, with an aim to provide a useful entry point for anyone seeking to engage with the technology in their area of interest.

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Topics: Transplantation (52%)


60 results found

Journal ArticleDOI: 10.1016/0378-5173(83)90064-9
Abstract: Porous hydrophilic discs were prepared from two grades of poly(vinyl alcohol) of varying degree of hydrolysis. The influence of the molecular size of the tracer used (potassium chloride, phenylpropanolamine hydrochloride and bovine serum albumin), that of the addition of a second water-soluble polymer poly(N-vinyl-2-pyrrolidone) and poly(ethylene glycol)) and the effect of the tracer/excipient ratio on the release profile were examined. Finally the role of the dynamic swelling and the dissolution of the polymer matrix on the release mechanism are discussed.

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Topics: Vinyl alcohol (55%), Ethylene glycol (55%), Polymer (51%) ... read more

3,906 Citations

Journal ArticleDOI: 10.1016/S0169-409X(01)00112-0
Juergen Siepmann1, Nicholas A. Peppas2Institutions (2)
Abstract: The objective of this article is to review the spectrum of mathematical models that have been developed to describe drug release from hydroxypropyl methylcellulose (HPMC)-based pharmaceutical devices. The major advantages of these models are: (i) the elucidation of the underlying mass transport mechanisms; and (ii) the possibility to predict the effect of the device design parameters (e.g., shape, size and composition of HPMC-based matrix tablets) on the resulting drug release rate, thus facilitating the development of new pharmaceutical products. Simple empirical or semi-empirical models such as the classical Higuchi equation and the so-called power law, as well as more complex mechanistic theories that consider diffusion, swelling and dissolution processes simultaneously are presented, and their advantages and limitations are discussed. Various examples of practical applications to experimental drug release data are given. The choice of the appropriate mathematical model when developing new pharmaceutical products or elucidating drug release mechanisms strongly depends on the desired or required predictive ability and accuracy of the model. In many cases, the use of a simple empirical or semi-empirical model is fully sufficient. However, when reliable, detailed information are required, more complex, mechanistic theories must be applied. The present article is a comprehensive review of the current state of the art of mathematical modeling drug release from HPMC-based delivery systems and discusses the crucial points of the most important theories.

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2,123 Citations

Open accessJournal Article
Abstract: In this paper we review the mathematical models used to determine the kinetics of drug release from drug delivery systems. The quantitative analysis of the values obtained in dissolution/release rates is easier when mathematical formulae are used to describe the process. The mathematical modeling can ultimately help to optimize the design of a therapeutic device to yield information on the efficacy of various release models.

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Topics: Drug delivery (55%)

1,891 Citations

Open accessJournal ArticleDOI: 10.1016/J.BIOMATERIALS.2015.08.045
01 Dec 2015-Biomaterials
Abstract: Gelatin methacryloyl (GelMA) hydrogels have been widely used for various biomedical applications due to their suitable biological properties and tunable physical characteristics. GelMA hydrogels closely resemble some essential properties of native extracellular matrix (ECM) due to the presence of cell-attaching and matrix metalloproteinase responsive peptide motifs, which allow cells to proliferate and spread in GelMA-based scaffolds. GelMA is also versatile from a processing perspective. It crosslinks when exposed to light irradiation to form hydrogels with tunable mechanical properties. It can also be microfabricated using different methodologies including micromolding, photomasking, bioprinting, self-assembly, and microfluidic techniques to generate constructs with controlled architectures. Hybrid hydrogel systems can also be formed by mixing GelMA with nanoparticles such as carbon nanotubes and graphene oxide, and other polymers to form networks with desired combined properties and characteristics for specific biological applications. Recent research has demonstrated the proficiency of GelMA-based hydrogels in a wide range of tissue engineering applications including engineering of bone, cartilage, cardiac, and vascular tissues, among others. Other applications of GelMA hydrogels, besides tissue engineering, include fundamental cell research, cell signaling, drug and gene delivery, and bio-sensing.

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Topics: Self-healing hydrogels (57%)

1,042 Citations

Journal ArticleDOI: 10.1016/S0032-3861(00)00287-1
M Krumova1, Daniel López1, Rosario Benavente1, Carmen Mijangos1  +1 moreInstitutions (1)
15 Dec 2000-Polymer
Abstract: Poly(vinyl alcohol) was crosslinked with hexamethylene diisocyanate in solution. A broad range of degrees of crosslinking, from 1.7 up to 74 mol% of reacted hydroxyl groups, was achieved. The variation of the thermal and mechanical properties of PVA with the crosslinking density show an initial decrease due to the diminution of the crystallinity of the system, caused by the crosslinking. After an abrupt rise at about 20%, the properties tend to level off independently on the increase of the crosslinking. This behaviour is explained as a result of the competitive action of at least three factors during the crosslinking: (i) weakening of the existing physical network due to hydrogen bonding; (ii) formation of a chemical network; and (iii) introduction of flexible moieties. The last factor is closely connected with the specific chemical structure of the crosslinker itself.

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450 Citations

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