Edge effect in hot embossing and its influence on global pattern replication of polymer-based microneedles / J. Zhuang in INTERNATIONAL POLYMER PROCESSING, Vol. XXXIV, N° 2 (05/2019)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXXIV, N° 2 (05/2019) . - p. 231-238 Titre : Edge effect in hot embossing and its influence on global pattern replication of polymer-based microneedles Type de document : texte imprimé Auteurs : J. Zhuang, Auteur ; D.-M. Wu, Auteur ; H. Xu, Auteur ; Y. Huang, Auteur ; Y. Liu, Auteur ; J.-Y. Sun, Auteur Année de publication : 2019 Article en page(s) : p. 231-238 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Effet de bord Gaufrage à chaud Micro-aiguilles Polyméthacrylate de méthyle Le poly(méthacrylate de méthyle) (souvent abrégé en PMMA, de l'anglais Poly(methyl methacrylate)) est un polymère thermoplastique transparent obtenu par polyaddition dont le monomère est le méthacrylate de méthyle (MMA). Ce polymère est plus connu sous son premier nom commercial de Plexiglas (nom déposé), même si le leader global du PMMA est Altuglas International9 du groupe Arkema, sous le nom commercial Altuglas. Il est également vendu sous les noms commerciaux Lucite, Crystalite, Perspex ou Nudec. Index. décimale : 668.4 Plastiques, vinyles Résumé : Hot embossing was used to fabricate a microneedle array on poly(methyl methacrylate) (PMMA) substrates. Both experimental and numerical researches were carried out to investigate the whole formation process. The results showed that the edge effect would significantly influence the replication rate of final products. An optimization design of convex flow barrier was proposed to improve the replication efficiency and structure uniformity. Furthermore, optimum parameters of the flow barrier were found to be 2 mm in length and 0.2 mm in height. Reasonable high molding temperature and force were conducive to reduce the filling time and increase the average height of microneedles. Note de contenu : - NUMERICAL SIMULATION : Physical and numerical modeling - Material properties - EXPERIMENTAL : Material and equipment - Experimental design - RESULTS AND DISCUSSION : Edge effect and optimization of structure uniformity - Influence of molding temperature and embossing force on mold filling in hot embossing process - Comparison of the average height of microneedles under different parameters based on the numerical and experimental results DOI : 10.3139/217.3726 En ligne : https://drive.google.com/file/d/1wyGC0z4P0QBNlnd5ayxq5ff6xuAhl9uZ/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=32397 [article]

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Elongated microparticles tuned for targeting hyaluronic acid delivery to specific skin strata in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Vol. 43, N° 6 (12/2021)  

[article]  inINTERNATIONAL JOURNAL OF COSMETIC SCIENCE > Vol. 43, N° 6 (12/2021) . - p. 738-747 Titre : Elongated microparticles tuned for targeting hyaluronic acid delivery to specific skin strata Type de document : document électronique Année de publication : 2021 Article en page(s) : p. 738-747 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cosméceutique Hyaluronique, acide L'acide hyaluronique est un type de polysaccharide (plus précisément une glycosaminoglycane) non fixé à une protéine centrale et largement réparti parmi les tissus conjonctifs, épithéliaux et nerveux animaux. Il se trouve notamment dans l'humeur vitrée et le liquide synovial. Il est l'un des principaux composants de la matrice extracellulaire ainsi que de certaines mucoprotéines lorsqu'il est associé à une fraction protéique. Depuis les années 1990, il est très utilisé dans divers dispositifs médicaux, médicamenteux et cosmétiques (présenté dans ce dernier cas comme "antistatique, humectant, hydratant, conditionneur cutané, anti-âge, etc."), bénéficiant d'un effet de mode grandement soutenu par une large publicité commerciale. Contribuant de façon significative à la prolifération et à la migration des cellules, l'acide hyaluronique est aussi impliqué dans la progression de certains cancers. (Wikipedia) Médicaments -- Administration par voie transcutanée Micro-aiguilles Particules (matières) Index. décimale : 668.5 Parfums et cosmétiques Résumé : - Objective : Microneedle or fractional laser applications are the most common topical delivery enhancement platforms. However, these methods of drug delivery are not skin strata specific. Drug delivery approaches which could target specific stratum of the skin remains a challenge. Elongated microparticles (EMPs) have been used in enhancing drug delivery into the skin. The aim of this study was to evaluate, for the first time, elongated silica microparticles with two different length profiles to enhance delivery of hyaluronic acid into different strata of human skin. - Methods : Two types of EMPs—long (milled EMPs) or short (etched EMPs) length ranges were characterized. A prototypical liquid formulation (Fluorescent hyaluronic acid) with and without EMP enhancement were evaluated for hyaluronic acid delivery in ex-vivo human skin. High performance liquid chromatography, Typhoon fluorescence scanning system, laser scanning confocal microscopy and reflectance confocal microscopy (RCM) were used to validate F-HA stability, visualize fluorescein in the skin, image the depth of F-HA delivery in the skin and define EMP penetration in skin strata, respectively. Statistical analysis was conducted using GraphPad Prism 6 software (GraphPad Software Inc, USA). - Results : Fluorescein-hyaluronic acid was stable and EMP enhanced skin penetration. RCM revealed that ‘etched EMP’ penetrated the skin to the stratum spinosum level. The vast majority (97.8%; p < 0.001) of the etched EMP did not penetrate completely through the viable epidermis and no obvious penetration into the dermis. In contrast, milled EMP showed 41-fold increase in penetration compared to the etched EMP but penetrated beyond the dermoepidermal junction. - Conclusion : EMPs can enhance delivery of hyaluronic acid. Using EMPs with defined length distributions, which can be tuned for a specific stratum of the skin, can achieve targeted hyaluronic acid delivery. Note de contenu : - MATERIALS AND METHODS : Materials - Methods - Statistical analysis - RESULTS : Fluorescein-hyaluronic acid stability evaluation by HPLC - Microscopic characterization of milled and etched EMP morphologies - Evaluation of EMP-enhanced F-HA delivery in ex-vivo human skin - Depth of F-HA delivery in ex vivo human skin with and without EMP - Penetration and distribution of etched EMPs versus milled EMPs in different skin strata DOI : https://doi.org/10.1111/ics.12749 En ligne : https://drive.google.com/file/d/1rI_PBk-fp2RlBwfxGg4kX6PKSLPQns4r/view?usp=shari [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37054 [article]

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Highly stable and fast-dissolving ascorbic acid-loaded microneedles / Jeerapond Leelawattanachai in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Vol. 45, N° 5 (10/2023)  

[article]  inINTERNATIONAL JOURNAL OF COSMETIC SCIENCE > Vol. 45, N° 5 (10/2023) . - p. 612-626 Titre : Highly stable and fast-dissolving ascorbic acid-loaded microneedles Type de document : texte imprimé Auteurs : Jeerapond Leelawattanachai, Auteur ; Kedsara Panyasu, Auteur ; Kornkanok Prasertsom, Auteur ; Supone Manakasettharn, Auteur ; Hathaiphat Duangdaw, Auteur ; Pitchaon Budthong, Auteur ; Naranya Thepphornbanchakit, Auteur ; Kullachate Muangnapoh, Auteur ; Sira Srinives, Auteur ; Dujduan Waraho-Zhmayev, Auteur ; Darapond Triampo, Auteur Année de publication : 2023 Article en page(s) : p. 612-626 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Dissolution (chimie) Formulation (génie chimique) -- Stabilité Micro-aiguilles Pénétration cutanée Polyéthylèneimine Systèmes de livraison (pharmacie) Tests de sécurité Vectorisation Vitamine C Index. décimale : 668.5 Parfums et cosmétiques Résumé : - Objectives : Ascorbic acid has many benefits to the skin. Numerous attempts to promote its topical delivery show great challenges since its chemical instability and poor skin impermeability. Microneedle delivery is a simple, safe, painless and effective means to deliver therapeutic or nourishing molecules into the skin. The purpose of this study was twofold : (a) to develop a new formulation of ascorbic acid-loaded microneedles to enhance ascorbic acid stability by investigating an optimal amount of polyethyleneimine as an additive to the dextran-based microneedle formulation and (b) to assess microneedle properties in terms of dissolving rate, skin penetration ability, biocompatibility and antimicrobial activity. - Methods : The microneedles formulated with ascorbic acid and varied polyethyleneimine concentrations were fabricated and subsequently tested for ascorbic acid stability using 2,2-diphenyl-1-picrylhydrazyl assay. The dissolution rate and skin penetration depth were investigated in porcine skin and the reconstructed human full-thickness skin model respectively. The skin irritation tests were done according to the Organisation for Economic Co-operation and Development Test Guideline No. 439. An antimicrobial disc susceptibility test was performed against Escherichia coli, Staphylococcus aureus and Staphylococcus epidermidis. - Results : Among varied amounts of 0%, 1.5%, 3.0% and 4.5% (w/v), the 3.0% polyethyleneimine showed the most desirable characteristics, including well-preserved shape integrity after demoulding, significantly improved stability of ascorbic acid (p < 0.001) from 33% to 96% antioxidant activity after 8 weeks of storage at 40°C, increased dissolving rate (p < 0.001) by being completely dissolved within 2 min after the skin insertion, passing skin penetration and biocompatibility tests as well as having a broad spectrum of antimicrobial property. - Conclusion : With a safety profile and enhanced properties, the new formulation of ascorbic acid-loaded microneedles shows outstanding potential as commercially available cosmetics and healthcare products. Note de contenu : - MATERIALS AND METHODS : Materials - Fabrication and characterization of AA-loaded dissolving microneedles - Stability test of AA-loaded microneedle after storage at various conditions - Fourier-transform infrared spectroscopy (FTIR) - Dissolution test of AA-loaded microneedles - In vitro skin permeation experiment with AA - Skin penetration experiment - Antimicrobial disc susceptibility test - Skin irritation test of AA-loaded microneedles - Statistical analysis - RESULTS AND DISCUSSION : Fabrication and characterization of AA-loaded microneedles - Stability test of AA-loaded microneedle after storage at various conditions - Dissolution test of AA-loaded microneedles - In vitro skin permeation experiment with AA - Skin penetration experiment - Antimicrobial disc susceptibility test - Skin irritation test of AA-loaded microneedles DOI : https://doi.org/10.1111/ics.12865 En ligne : https://drive.google.com/file/d/1A7uzPuS6f_fW_vYCVoxz74idDbVfUPQO/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40088 [article]

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Predicting the replication fidelity of injection molded solid polymer microneedles / Tim Evens in INTERNATIONAL POLYMER PROCESSING, Vol. 37, N° 3 (2022)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. 37, N° 3 (2022) . - p. 237-254 Titre : Predicting the replication fidelity of injection molded solid polymer microneedles Type de document : texte imprimé Auteurs : Tim Evens, Auteur ; Sylvie Castagne, Auteur ; David Seveno, Auteur ; Albert Van Bael, Auteur Année de publication : 2022 Article en page(s) : p. 237-254 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Matières plastiques -- Moulage par injection Micro-aiguilles Polycarbonates Polypropylène Prévision, Théorie de la Réplication (technologie) Simulation par ordinateur Index. décimale : 668.9 Polymères Résumé : Microneedles are sharp microscopic features, which can be used for drug or vaccine delivery in a minimally invasive way. Recently, we developed a method to produce polymer microneedles using laser ablated molds in an injection molding process. At this moment, extensive injection molding experiments are needed to investigate the replication fidelity. Accurate predictions of the injection molding process would eliminate these costly and time expensive experiments. In this study, we evaluated the replication fidelity of solid polymer microneedles using numerical simulations and compared the results to injection molding experiments. This study was performed for different sizes of microneedles, different thermoplastics (polypropylene and polycarbonate) and different mold materials (tool steel, copper alloy and aluminium alloy). Moreover, different processing conditions and different locations of the microneedles on the macroscopic part were considered. A good correlation with experimental findings was achieved by optimizing the heat transfer coefficient between the polymer and the mold, while using a multiscale mesh with a sufficient number of mesh elements. Optimal heat transfer coefficients between 10,000 and 55,000 W/m2 K were found for the different combinations of polymer and mold materials, which resulted in an accuracy of the simulated microneedle replication fidelity between 94.5 and 97.0%. Note de contenu : - MATERIALS AND METHODS : Thermoplastic polymers - Mold insert - Injection molding product - Injection molding experiments - INJECTION MOLDING SIMULATIONS SETTINGS : It can be assumed that the macroscopic flow - Simulation parameters in Moldex3D - Mesh convergence study using multi-scale meshing - Heat transfer coefficient - Replication fidelity in function of the location of the microfeatures - Replication fidelity in function of the injection molding parameter - Replication fidelity in function of the mold material - RESULTS AND DISCUSSION : Macroscopic flow - Mesh convergence study - Effect of the heat transfer coefficient - Replication fidelity in function of the location of the microfeatures - Replication fidelity in function of the injection molding parameters - Replication fidelity in function of the mold material - Table 1 : Main properties of the thermoplastics based on material datasheets and the Moldex3D 2020 material database - Table 2 : Thermal properties of the different mold materials based on material datasheets - Table 3 : Injection molding process parameters for the two thermoplastic materials - Table 4 : Default and adapted simulation parameters in Moldex3D - Table 5 : Adapted injection molding process parameters for the two thermoplastic materials - Table 6 : Heat transfer coefficients, corresponding to a minimal average absolute deviation between the simulated and experimentally determined replication fidelity, for the PP and PC in combination with the tool steel, the aluminium alloy and the copper alloy mold insert DOI : https://doi.org/10.1515/ipp-2021-4207 En ligne : https://drive.google.com/file/d/1oNumrisvhCE-7j_vpdYOWG6Ed6AmPXcr/view?usp=shari [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37904 [article]

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