Academic literature on the topic 'PLA-PEG'
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Journal articles on the topic "PLA-PEG"
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Jeong, Heeseok, Hyunju Lim, Deuk Yong Lee, Yo-Seung Song, and Bae-Yeon Kim. "Preparation and Drug Release Behavior of Nifedipine-Loaded Poly(lactic acid)/Polyethylene Glycol Microcapsules." Journal of Nanoscience and Nanotechnology 21, no. 7 (2021): 3735–41. http://dx.doi.org/10.1166/jnn.2021.19168.
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Nifedipine (NF)-loaded poly(lactic acid) (PLA) and PLA/polyethylene glycol (PLA/PEG) microcapsules are synthesized using a high-speed agitator and a syringe pump with an oil-in-water emulsion-solvent evaporation technique to evaluate the effect of PLA/PEG ratio on morphology and drug release behavior of the capsules. Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimeter (DSC), and X-ray diffraction (XRD) results indicate that PEG reacts successfully with PLA due to the ether bond between PEG and PLA. The drug release rate of PLA and PLA/PEG capsules increases dramatically from 0 to 5 min and then reaches a plateau within 15 to 20 min. Due to the high specific surface area, the amount of NF released is raised by reducing the PLA concentration from 5 wt% to 2 wt%. Unlike PLA capsules, the drug release rate of PLA/PEG capsules increases due to the size effect by varying the PLA/PEG ratio from 10/0 to 6/4. Larger PLA/PEG capsules are attributed to higher amounts of encapsulated NF. The capsules show no evidence of cytotoxicity, suggesting that the PLA and PLA/PEG drug carriers are clinically safe.
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Mohd Asri, Syazeven Effatin Azma, Zainoha Zakaria, Azman Hassan, Mohamad Haafiz Mohamad Kassim, and Reza Arjmandi. "Exploring the Effects of Fermented Chitin Nanowhiskers on Tensile and Thermal Properties of Poly(ethylene glycol) modified Polylactic Acid Nanocomposites." Malaysian Journal of Fundamental and Applied Sciences 17, no. 2 (2021): 154–65. http://dx.doi.org/10.11113/mjfas.v17n2.2002.
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The incorporation of fermented chitin nanowhiskers (FCHW) into poly(lactic acid) (PLA) increased the tensile modulus and strength of PLA at the expense of ductility. The brittleness of PLA can be overcome with the use of plasticizer such as polyethylene glycols (PEG). The objective of this study is to investigate the effect of FCHW on the tensile and thermal properties PLA incorporated with PEG as plasticizer (PLA/PEG). PLA/PEG and FCHW reinforced PLA/PEG nanocomposites were prepared using solution mixing technique. Thermogravimetric analysis (TGA) was used to determine the thermal properties while tensile properties were determined from the tensile test. The incorporation of PEG successfully increased the ductility and tensile strength of PLA at the expense of modulus. Based on the tensile properties, 5 phr PEG was chosen for further investigation on the effect of FCHW on PEG modified PLA. Incorporation of 1 phr FCHW PLA/PEG increased the tensile strength and Young’s modulus. However, the tensile strength decreased with further addition of FCHW. The elongation at break of PLA/PEG decreased drastically with the incorporation of 1 phr FCHW and decreased gradually with further increase of FCHW. The thermal stability from TGA of FCHW reinforced PLA/PEG nanocomposites at 5 phr FCHW content was observed to be significantly higher compared to PLA/PEG, as indicated by T20 and Tmax.
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Zhang, Zhao, Guo Dong Fan, and Hai Yan Yang. "Study on Chain Extension and Modification of Poly(Lactic Acid) by Isophorone Diisocyanate /Polyethylene Glycol." Advanced Materials Research 476-478 (February 2012): 2067–70. http://dx.doi.org/10.4028/www.scientific.net/amr.476-478.2067.
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Poly(lactic acid)(PLA)was end-capped by isophorone diisocyanate(IPDI) to get PLA-IPDI under the condition of temperature of 176°C and pressure of 0.090 MPa for 13 mins, and then the PLA-IPDI was chain-extended with different molecular weights polyethylene glycol (PEG)-400, PEG-600, PEG-800, PEG-4000 and PEG-6000 to produce a series of block copolymer PLA-IPDI-PEGs. when n(–OH)/n(–NCO)=1.5:1, the molecular weight of PLA-IPDI is maximum. All the copolymer PLA-IPDI-PEGs were characterized by GPC, FTIR, DSC and contact angle testing. The results show that the polymeric degree of PLA-IPDI-PEG-800 is the best and its molecular weight is the biggest. Tg of PLA-IPDI-PEG-800 is the lowest and its hydrophilicity is better than the others modification PLA-IPD-PEGs and pure PLA.
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Mohd. Akhir, Nur Atiqah, Maizatulnisa Othman, Yose Fachmi Buys, Norhashimah Shaffiar, Dzun Noraini Jimat, and Sharifah Imihezri Syed Shaharuddin. "CHARACTERISATION AND PRODUCTION OF POLY (LACTIC ACID)/POLY(ETHYLENE GLYCOL) MICROFIBER VIA MELT DRAWN SPINNING PROCESS." IIUM Engineering Journal 22, no. 1 (2021): 201–12. http://dx.doi.org/10.31436/iiumej.v22i1.1364.
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In this study, melt blended compositions of pure PLA with additions of polyethylene glycol (PEG) up to 30 wt% were prepared. Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), and thermogravimetric analysis (TGA) were used to investigate the properties of PLA/PEG blends, such as structural, thermal, and morphological properties. The results showed that further increments of PEG cause the -OH group of PLA/PEG blends to show a broad peak, indicating that there is hydrogen bonding interaction between PEG and PLA chains. DSC result revealed that the addition of PEG decreases the glass transition temperature from 57 °C to 46 °C and crystallization temperature from 107 °C to 87 °C. Such trends suggest enhanced chain mobility of PLA chains. TGA thermograms showed that further additions of PEG into PLA resulted in a consistent shift to lower temperature and decrease in thermal stability. Optical microscopy (OM) and scanning electron microscopy (SEM) observations of the melt spun PLA/PEG microfibers revealed that the diameter of the microfibers averaged between 15 to 80 microns. ABSTRAK: Kajian ini menganalisa komposisi adunan lebur PLA asli bersama tambahan polietilena glikol (PEG) sebanyak 30%. Penjelmaan Fourier spektroskopi inframerah (FTIR), kalorimeter pengimbasan pembezaan (DSC) dan analisis termogravimetri (TGA) telah digunakan bagi mengkaji sifat-sifat adunan PLA/PEG, seperti struktur, terma dan sifat-sifat morfologi. Keputusan menunjukkan penambahan PEG seterusnya menyebabkan kumpulan -OH campuran PLA/PEG memberikan puncak yang lebar, ini menunjukkan ada interaksi ikatan hidrogen antara rantaian PEG dan PLA. Keputusan DSC menunjukkan penambahan PEG mengurangkan perubahan gelas dari 57 °C kepada 46 °C dan suhu kristalisasi dari 107 °C kepada 87 °C. Trend ini mencadangkan peningkatan pergerakan rangkaian pada rantaian PLA. Termogram TGA menunjukkan dengan penambahan berterusan PEG ke dalam PLA menghasilkan penurunan konsisten pada suhu dan pengurangan kestabilan haba. Pemerhatian mikroskop optik (OM) dan mikroskopi elektron penskanan (SEM) mikrofiber spun lebur PLA/PEG menunjukkan purata diameter mikrofiber ini antara 15 ke 80 mikron.
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Hendrick, Erin, and Margaret Frey. "Increasing Surface Hydrophilicity in Poly(Lactic Acid) Electrospun Fibers by Addition of Pla-b-Peg Co-Polymers." Journal of Engineered Fibers and Fabrics 9, no. 2 (2014): 155892501400900. http://dx.doi.org/10.1177/155892501400900219.
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Poly (lactic acid) – b – poly (ethylene glycol) (PLA-b-PEG) co-polymers with block lengths of 1000–750, 5000–1000, 1000–5000, and bulk PEG were added to PLA electrospinning dopes to create hydrophilic but non-water soluble nanofibers. PLA-b-PEG block lengths strongly affected the total amount of PEG that could be incorporated, as well as spinnability and fiber morphology. Solutions containing >1% w/w of the lowest molecular weight co-polymer PLA (1000) – b – PEG (750) formed an unspinnable, cloudy gel. Addition of the PLA (5000) – b – PEG (1000) to the base spinning solution influenced fiber diameters and spinnability in the same manner as simply increasing PLA concentration in the spinning dope. Addition of PLA (1000) – b – PEG (5000) resulted in decreased fiber diameters, and allowed for the highest overall co-polymer loading. In final fiber formulations, maximums of 0.9, 2.9 and 9.3 wt% PEG could be achieved using the PLA-b-PEG 1000–750, 5000–1000 and 1000–5000 respectively. PEG (MW = 3350 g/mol) homopolymer was added to the spinning dopes to prepare fibers with 1.0 and 5.0 wt% PEG. The resulting fibers had non-uniform morphology and more variable diameter size than occurred with the addition of PEG in block co-polymer form. Water absorbance by electrospun nonwoven fabrics increased by four times over the control PLA with the addition of 1.0 wt% PEG, and by eighteen times with the addition of 9.3 wt% PEG with the block co-polymers. At similar overall PEG loadings, the addition of PLA-b-PEG resulted in a two to four fold increase in water wicking over the addition of PEG homopolymer.
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Thong, Phan Quoc. "STRUCTURE AND PROPERTIES OF Fe3O4 NANOPARTICLES COATED BY PLA-PEG COPOLYMER WITH AND WITHOUT LOADING OF CURCUMIN." Vietnam Journal of Science and Technology 54, no. 1A (2018): 268. http://dx.doi.org/10.15625/2525-2518/54/1a/11837.
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Nanoparticles (NPs) of poly(lactide)-polyethylene glycol (PLA-PEG) with PLA:PEG (3:1, w/w) component ratio was prepared by ring opening polymerization of Lactide for preparation of Fe3O4@PLA-PEG and Fe3O4@PLA-PEG/Cur nanosystem. The Cur (curcumin) loaded Fe3O4 could be used as multi-functional nano drugs beneficiating both the image contrast enhancement and locally controlled heating. The size, shape, surface bonding of Fe3O4@PLA-PEG, Fe3O4@PLA-PEG/Cur nanosystems were determined by Field Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy (TEM), Thermal Gravity Analysis (TGA), Fourier Transform Infrared Spectroscopy (FT-IR); while magnetic characteristics by Vibrating Sample Magnetometer (VSM). The research suggests that Fe3O4@PLA-PEG and Fe3O4@PLA-PEG/Cur nanosystems exhibit properties of great potential for biomedical applications, both for diagnosis and treatment purposes.
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Thongpina, Chanchai, Chaiwat Tippuwanan, Kwanchai Buaksuntear, and Teerani Chuawittayawuta. "Mechanical and Thermal Properties of PLA Melt Blended with High Molecular Weight PEG Modified with Peroxide and Organo-Clay." Key Engineering Materials 751 (August 2017): 337–43. http://dx.doi.org/10.4028/www.scientific.net/kem.751.337.
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The thermal and mechanical properties of poly (lactic acid) blended with high molecular weight PEG, i.e. PEG1000 and PEG6000 were compared. The contents of PEG added were 10, 12.5 and 15 % by weight, with respect to PLA. The PLA/PEG blends were modified by addition of organic peroxide in order to induced crosslinking. Addition of organic modified montmorrillonite (Cloisite 30B, C30B) was also performed in order to modify mechanical performance of PLA/PEG blends. C30B was prepared via master batch in PLA. Morphology, crystallization, thermal stability and mechanical properties of the blends were investigated using SEM, DSC, TGA and universal testing macine, respectively. Morphology of cryogenic fracture surface showed smooth brittle surface. PEG1000 well plasticized PLA where as PEG6000 shows better thermal stability and mechanical properties. The presence of PEG induced PLA to perform cold crystallization. Tm in PLA was slightly changed whereas degree of crystallinity of PLA was improved by PEG but slightly decreased by peroxide. The thermal stability of PLA was enhanced with the addtion of PEG6000. The toughening of PLA was confirmed by the increment of elongation at break. The exfoliation of C30B was interfered by the crosslink PLA. Then tensile strength of PLA/PEG/C30B/Luperox101 was then suppressed. The optimum properties, in term of toughening and thermal stability, were found at PEG content of 10 % rather than 15% by weight, for both PEG1000 and PEG6000.
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Somphol, Wanasorn, Thipjak Na Lampang, Paweena Prapainainar, et al. "Effect of Polyethylene Glycol in Nanocellulose/PLA Composites." Key Engineering Materials 821 (September 2019): 89–95. http://dx.doi.org/10.4028/www.scientific.net/kem.821.89.
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Poly (lactic acid) or PLA was reinforced by nanocellulose and polyethylene glycol (PEG), which were introduced into PLA matrix from 0 to 3 wt.% to enhance compatibility and strength of the PLA. The nanocellulose was prepared by TEMPO-mediated oxidation from microcrystalline cellulose (MCC) powder and characterized by TEM, AFM, and XRD to reveal rod-like shaped nanocellulose with nanosized dimensions, high aspect ratio and high crystallinity. Films of nanocellulose/PEG/PLA nanocomposites were prepared by solvent casting method to evaluate the mechanical performance. It was found that the addition of PEG in nanocellulose-containing PLA films resulted in an increase in tensile modulus with only 1 wt% of PEG, where higher PEG concentrations negatively impacted the tensile strength. Furthermore, the tensile strength and modulus of nanocellulose/PEG/PLA nanocomposites were higher than the PLA/PEG composites due to the existence of nanocellulose chains. Visual traces of crazing were detailed to describe the deformation mechanism.
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Cavalli, Leticia Riboldi, Jalma Maria Klein, Ivana Greice Sandri та Rosmary Brandalise. "Este trabajo se centró en el desarrollo de envases activos biodegradables con mezclas de poli (ácido láctico) (PLA), poli (etileno-co-acetato de vinilo) (EVA), polietilenglicol (PEG) y quitosano (QUI). Se investigaron las características morfológicas térmicas y mecánicas de las mezclas, así como, al mismo tiempo, la actividad antifúngica del envase. Para evaluar la actividad antimicrobiana de las mezclas PLA/EVA/PEG/QUI, las muestras se insertaron entre rebanadas de pan sin conservantes para evaluar su vida útil. Al comparar entre PLA/EVA/PEG, mezclas de PLA/EVA/PEG/QUI y PLA puro fue posible evidenciar la miscibilidad parcial, la disminución de la temperatura de transición vítrea (Tg) al incorporar PEG en las mezclas, una disminución de la fuerza fl exural del 71% y módulo de elasticidad del 80,4% a la mezcla PLA/ EVA/PEG/2.5QUI, así como un aumento del alargamiento a la rotura del 153% y del 392% a la tenacidad al impacto. Se observó un comportamiento similar a PLA/EVA/20PEG y PLA/EVA/PEG/5.0QUI. La película que contiene QUI entre las rebanadas de pan también influyó en la reducción de la actividad del agua y redujo aproximadamente un 35% en el recuento de mohos y levaduras en las rebanadas de pan. El quitosano en mezclas con PLA/EVA/PEG mostró potencial como agente antifúngico natural en envases de panadería." Research, Society and Development 10, № 9 (2021): e50010916964. http://dx.doi.org/10.33448/rsd-v10i9.16964.
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This work focused on the development of biodegradable active packaging with poly(lactic acid) (PLA), poly(ethylene-co-vinyl acetate) (EVA), polyethylene glycol (PEG) and chitosan (QUI) blends. It investigated thermal and mechanical morphological characteristics of the blends, as the same time, the antifungal activity of the packaging. To assess the antimicrobial activity of the PLA/EVA/PEG/QUI blends, the samples were inserted between slices of bread with no preservative to the evaluation of their shelf life. By comparing between PLA/EVA/PEG, PLA/EVA/PEG/QUI blends and neat PLA was possible to evidence the partial miscibility, decreased glass transition temperature (Tg) by incorporating PEG into the blends, a decrease in flexural strength of 71% and elasticity modulus of 80.4% to PLA/EVA/PEG/2.5QUI blend, as well as an increase in elongation at break of 153% and 392% to impact toughness. A similar behavior was observed to PLA/EVA/20PEG and PLA/EVA/PEG/5.0QUI. The QUI-containing film among the bread slices has also influenced the water activity reduction, and reduced about 35% in the count of molds and yeasts in the slices of bread. Chitosan in mixtures with PLA/EVA/PEG showed potential as a natural antifungal agent in bakery packaging.
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Shen, Peng, Kai Tu, Chang Yu Yang, Jian Li, and Ru Xu Du. "Preparation of Anti-Fouling Poly(Lactic Acid)(PLA) Hollow Fiber Membranes via Non-Solvent Induced Phase Separation." Advanced Materials Research 884-885 (January 2014): 112–16. http://dx.doi.org/10.4028/www.scientific.net/amr.884-885.112.
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Anti-fouling PLA hollow fibers were fabricated using synthesized PLA-PEG-PLA copolymer as an additive to improve the hydrophilicity. The tri-block copolymer was prepared by ring-opening polymerization and a hydrophilic copolymer processing good compatibility with PLA molecule was obtained and utilized to fabricate membrane with PLA by NIPS. Elemental analysis showed that PLA-PEG-PLA could stably exist in membranes and endow the membrane with persistent hydrophilic. Thus the contact angle decreased nearly 20o with 5% PLA-PEG-PLA content, resulting in higher water permeability and BSA rejection which indicated the anti-fouling property of PLA membrane was improved.
Dissertations / Theses on the topic "PLA-PEG"
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Mainardes, Rubiana Mara [UNESP]. "Desenvolvimento de nanopartículas de PLA e PLA-PEG para administração intranasal de zidovudina." Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/102462.
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mainardes_rm_dr_arafcf.pdf: 1864850 bytes, checksum: f49ab7e28e985faad2f32205305f0de3 (MD5)<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)<br>Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)<br>Universidade Estadual Paulista (UNESP)<br>A zidovudina (AZT) é um fármaco amplamente usado no tratamento da síndrome da imunodeficiência adquirida. O AZT apresenta baixa biodisponibilidade oral pois sofre rápido e extenso metabolismo de primeira passagem hepática, além de curto t1/2. Sendo assim, altas e freqüentes doses são requeridas para se manter concentrações plasmáticas efetivas e, dessa maneira, apresenta graves efeitos colaterais, dose-dependentes, que limitam o seu uso em determinados tipos de pacientes. As nanopartículas são eficientes sistemas poliméricos que contribuem para a redução da toxicidade de fármacos, pois são capazes de liberá-los de maneira prolongada, proporcionando maior tempo de contato do fármaco com o plasma e tecidos. A via de administração intranasal é uma rota interessante, quando se deseja evitar o metabolismo de primeira passagem e, também, pode oferecer um ótimo perfil de absorção para nanopartículas. Neste trabalho, estudouse a incorporação de AZT em nanopartículas de PLA e de blendas de PLA-PEG com diferentes razões molares. A caracterização físico-química demonstrou que a presença do PEG influenciou a forma, o diâmetro médio, a eficiência de encapsulação, assim como o potencial de superfície das partículas. O diâmetro médio e a eficiência de encapsulação das nanopartículas aumentaram com o aumento crescente da razão molar de PEG na blenda. A forma geral e a apresentação das partículas variaram em função da concentração de PEG, sendo que os melhores resultados foram obtidos com as menores razões molares deste na blenda. Os experimentos de liberação in vitro mostraram que a liberação do AZT a partir das nanopartículas foi mais lenta em relação ao AZT em solução. A presença do PEG nas nanopartículas alterou o perfil de liberação do AZT, tornando...<br>Zidovudine (AZT) is a drug widely used in the treatment of acquired immunodeficiency syndrome. AZT shows low bioavailability because it suffers fast and extensive by pass hepatic metabolism, besides of low t1/2. High and frequent doses are requested to achieve effective plasmatic concentrations, and thus, it shows serious and dosedependents side effects that limit its use in certain kind of patients. Nanoparticles are efficient polymeric systems that contributes to reduce the drug toxicity, because maintain prolonged drug release, making longer the contact between drug and plasma/tissues. The intranasal way is a very interesting route to avoid the by pass metabolism, and also offers a great absorption profile to nanoparticles. In the present work, the AZT encapsulation in PLA e PLA-PEG blends nanoparticles was studied. The physico-chemical characterization showed that the presence of PEG influences the nanoparticles shape, mean diameter, encapsulation efficiency and superficial charge. The mean diameter and encapsulation efficiency increase with increasing PEG proportion in the blend. The nanoparticles shape varied in function of PEG concentration, the better results being obtained with the lowest PEG concentration. In vitro experiments showed that AZT release from nanoparticles was slower than that of AZT solution. The presence of PEG in nanoparticles altered the AZT release profile, making it faster than that from PLA nanoparticles. The ex vivo phagocytosis experiments demonstrated that PLA-PEG blends nanoparticles were more efficient in avoiding the activation of phagocytic cells. The intranasal bioavailability in rats shows that blend PLA-PEG nanoparticles demonstrated longer plasmatic circulating times than that those make of PLA alone. These results demonstrate that PLA and PLA-PEG blends nanoparticles can be used as an efficient intranasal drug delivery system.
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Mainardes, Rubiana Mara. "Desenvolvimento de nanopartículas de PLA e PLA-PEG para administração intranasal de zidovudina /." Araraquara : [s.n.], 2007. http://hdl.handle.net/11449/102462.
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Orientador: Maria Palmira Daflon Gremião<br>Banca: Raul Cesar Evangelista<br>Banca: Leila Aparecida Chiavacci<br>Banca: Célio Lopes Silva<br>Banca: Marco Vinícius Chaud<br>Resumo: A zidovudina (AZT) é um fármaco amplamente usado no tratamento da síndrome da imunodeficiência adquirida. O AZT apresenta baixa biodisponibilidade oral pois sofre rápido e extenso metabolismo de primeira passagem hepática, além de curto t1/2. Sendo assim, altas e freqüentes doses são requeridas para se manter concentrações plasmáticas efetivas e, dessa maneira, apresenta graves efeitos colaterais, dose-dependentes, que limitam o seu uso em determinados tipos de pacientes. As nanopartículas são eficientes sistemas poliméricos que contribuem para a redução da toxicidade de fármacos, pois são capazes de liberá-los de maneira prolongada, proporcionando maior tempo de contato do fármaco com o plasma e tecidos. A via de administração intranasal é uma rota interessante, quando se deseja evitar o metabolismo de primeira passagem e, também, pode oferecer um ótimo perfil de absorção para nanopartículas. Neste trabalho, estudouse a incorporação de AZT em nanopartículas de PLA e de blendas de PLA-PEG com diferentes razões molares. A caracterização físico-química demonstrou que a presença do PEG influenciou a forma, o diâmetro médio, a eficiência de encapsulação, assim como o potencial de superfície das partículas. O diâmetro médio e a eficiência de encapsulação das nanopartículas aumentaram com o aumento crescente da razão molar de PEG na blenda. A forma geral e a apresentação das partículas variaram em função da concentração de PEG, sendo que os melhores resultados foram obtidos com as menores razões molares deste na blenda. Os experimentos de liberação in vitro mostraram que a liberação do AZT a partir das nanopartículas foi mais lenta em relação ao AZT em solução. A presença do PEG nas nanopartículas alterou o perfil de liberação do AZT, tornando...(Resumo completo, clicar acesso eletrônico abaixo)<br>Abstract: Zidovudine (AZT) is a drug widely used in the treatment of acquired immunodeficiency syndrome. AZT shows low bioavailability because it suffers fast and extensive by pass hepatic metabolism, besides of low t1/2. High and frequent doses are requested to achieve effective plasmatic concentrations, and thus, it shows serious and dosedependents side effects that limit its use in certain kind of patients. Nanoparticles are efficient polymeric systems that contributes to reduce the drug toxicity, because maintain prolonged drug release, making longer the contact between drug and plasma/tissues. The intranasal way is a very interesting route to avoid the by pass metabolism, and also offers a great absorption profile to nanoparticles. In the present work, the AZT encapsulation in PLA e PLA-PEG blends nanoparticles was studied. The physico-chemical characterization showed that the presence of PEG influences the nanoparticles shape, mean diameter, encapsulation efficiency and superficial charge. The mean diameter and encapsulation efficiency increase with increasing PEG proportion in the blend. The nanoparticles shape varied in function of PEG concentration, the better results being obtained with the lowest PEG concentration. In vitro experiments showed that AZT release from nanoparticles was slower than that of AZT solution. The presence of PEG in nanoparticles altered the AZT release profile, making it faster than that from PLA nanoparticles. The ex vivo phagocytosis experiments demonstrated that PLA-PEG blends nanoparticles were more efficient in avoiding the activation of phagocytic cells. The intranasal bioavailability in rats shows that blend PLA-PEG nanoparticles demonstrated longer plasmatic circulating times than that those make of PLA alone. These results demonstrate that PLA and PLA-PEG blends nanoparticles can be used as an efficient intranasal drug delivery system.<br>Doutor
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Oliveira, Samantha Sant'Anna Marotta de. "Nanopartículas de PLA e PLA-PEG contendo tamoxifeno: preparação, caracterização e avaliação in vitro e in vivo." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/60/60137/tde-31102014-110511/.
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O câncer de mama constitui o segundo tipo de câncer mais frequente no mundo e o mais comum entre as mulheres, representando uma das principais causas de morte. O tamoxifeno é um fármaco antiestrogênico utilizado para o tratamento deste tipo de câncer desde 1971 e ainda é o mais utilizado nos casos de tumores mamários que expressam receptores de estrógeno. Apesar de apresentar resultados significativamente positivos, seu efeito antiestrogênico não se restringe apenas ao sítio tumoral causando, com isso, efeitos colaterais graves que podem deixar sequelas. A proposta deste trabalho foi desenvolver sistemas de liberação nanoparticulados à base de PLA e PLA-PEG para veiculação do tamoxifeno, como uma estratégia para o potencial aumento da segurança e da eficácia deste fármaco através de um possível direcionamento passivo ao sítio de ação, devido à permeabilidade vascular aumentada destas regiões tumorais. As nanopartículas foram preparadas pela técnica de nanoprecipitação e apresentaram diâmetro médio inferior a 200 nm para a maioria das formulações. Foram avaliados três estabilizantes, o poloxamer 407, o poloxamer 188 e o polissorbato 80, este último proporcionou maior eficiência de encapsulação, 86,7% e 100%, nas nanopartículas de PLA e PLA-PEG, respectivamente. Quanto à composição das nanopartículas de PLA-PEG, o polímero utilizado inicialmente (PLA(1000)-PEG(750)) apresentou distribuição de tamanho heterogênea, perfil multimodal e alto índice de polidispersividade. Assim, este polímero foi substituído pelo PLA(5000)-PEG(1000), que apresentou distribuição de tamanho uniforme, perfil monomodal e baixo índice de polidispersividade. A caracterização por microscopia eletrônica de varredura comprovou a homogeneidade no tamanho de partícula, mostrando seu formato esférico. As análises de espectrofotometria no infravermelho e calorimetria diferencial exploratória sugeriram que não ocorreu nenhum tipo de interação ou reação entre o fármaco e os demais componentes das formulações. Dois métodos analíticos para a determinação do tamoxifeno foram validados com sucesso por CLAE e espectroscopia UV-vis. O perfil de liberação in vitro do tamoxifeno a partir das nanopartículas de PLA apresentou característica sustentada e alcançou 50% em 180 h, tendo sido totalmente liberado após 288 h. Já as nanopartículas de PLA(5000)-PEG(1000) liberaram apenas 16,9% do fármaco após 216 h. A liberação do fármaco a partir das nanopartículas foi muito mais lenta comparada ao tamoxifeno não encapsulado, evidenciando a vantagem da incorporação do fármaco em nanopartículas compostas por PLA e PLA-PEG. No estudo do perfil de concentração plasmática em ratas Wistar, não foi possível detectar o fármaco e seu principal metabólito pelo método por CLAE desenvolvido, sugerindo que os sistemas nanoparticulados tenham extravasado rapidamente para os órgãos.<br>Breast cancer is the second most frequent type of cancer in the world and it is the most common among women, representing a major cause of death. Tamoxifen is an antiestrogen drug used in the treatment of this type of cancer since 1971 and it is the most employed drug in the treatment of breast cancer subtypes that expresses estrogen receptors. Despite presenting significantly positive results, its antiestrogen effect is not restricted to the tumour site, causing, as consequence, severe side effects. The purpose of this work was to develop nanostructured drug delivery systems based on PLA and PLA-PEG loaded with tamoxifen, as a strategy to potentially increase the safety and efficacy of this drug through a possible passive accumulation the site of action, due to the enhanced vascular permeability of tumour sites. Nanoparticles were prepared by the nanoprecipitation technique and presented average diameter smaller than 200 nm for the majority of the formulations. Three stabilizing adjuvants were analysed, poloxamer 407, poloxamer 188 and polysorbate 80 and the last one yielded the highest encapsulation efficiency, 86.7% and 100%, for the PLA and PLA-PEG nanoparticles, respectively. Regarding the PLA-PEG nanoparticles composition, the first polymer employed was (PLA(1000)-PEG(750)), which presented heterogeneous particle size distribution, multimodal profile and high polydispersity index. So, it was replaced by PLA(5000)-PEG(1000), which exhibited uniform particle size distribution, monomodal profile and low polydispersity index. The characterization by scanning electron microscopy confirmed the homogeneity of particles size, evidencing their spherical shape. Infrared spectrophotometry and differential scanning calorimetry analysis suggested that any interaction or reaction had occurred between the drug and the other components of the formulations. Two analytical methods for tamoxifen quantification were successfully validated by HPLC and UV-vis spectroscopy. In vitro tamoxifen release profile from PLA nanoparticles presented sustained release and reached 50% in 180 h, being completely released after 288 h, whereas PLA(5000)-PEG(1000) nanoparticles released only 16.9% of tamoxifen after 216 h. Drug release from nanoparticles was much slower compared to the non-encapsulated tamoxifen, showing the advantage of nanoparticles composed of PLA and PLA-PEG. In the plasmatic concentration profile study carried out in Wistar rats, it was not possible to detect tamoxifen or its main metabolite by the HPLC method, suggesting that nanoparticles quickly extravased to organs.
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Stéfani, Muriel. "Comportement de nanoparticules furtives PLA-PEG : approche par des copolymères biorésorbables modèles." Montpellier 1, 1998. http://www.theses.fr/1998MON13520.
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Gontard, Gwenaëlle. "Synthèse de nanoconjugués PEG-PLA pour des applications biomédicales : libération contrôlée et Imagerie." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30279.
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Ce travail de thèse s’inscrit dans le cadre d’une collaboration entre Sanofi à Vitry-sur-Seine et le Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA) à Toulouse, et a pour but de développer de nouveaux nanovecteurs à base de conjugués polymériques biodégradables et biocompatibles capables d’encapsuler, de transporter et de libérer des agents thérapeutiques. Les travaux précédemment réalisés au laboratoire, ont montré que la libération de principes actifs hydrophobes, tels que le Cabazitaxel de la famille des taxanes, pouvait être contrôlée grâce à l’architecture de conjugués de nature PEG-PLA. Dans le premier chapitre, une étude a été menée afin d’améliorer la cinétique de libération du principe actif, en tirant profit de la différence de pH qui réside entre les tissus sains et les tissus cancéreux. Différents liens (reliant le principe actif au copolymère) ayant un comportement pH dépendant ont été étudiés, comme l’hydrazone, l’acétal et le β-thiopropionate. La liaison ester boronique, dynamique en fonction du pH, a aussi été étudiée dans le but de déstructurer la NP et permettre indirectement d’améliorer la libération du principe actif. La synthèse et l’évaluation des divers conjugués ont montré que la structure polymérique amphiphile des conjugués inhibait considérablement le comportement pH dépendant attendu. Dans le second chapitre, plusieurs technologies comme le ciblage, permettant de diriger la NP dans l’organisme, ou l’imagerie permettant de les visualiser, ont été étudiées. L’influence de la structure des conjugués de forme Y et L sur les propriétés de reconnaissance et d’imagerie a été analysée. La structure Y offre quelques avantages quant à la quantité de ligand requise pour obtenir un ciblage actif optimal ainsi qu’une meilleure visualisation, en comparaison des résultats obtenus avec les conjugués L. La méthode de co-nanoformulation a permis de faire varier la quantité de ligand ou de sonde d’imagerie au sein des NPs. Dans le troisième chapitre, la synthèse et l’efficacité de sels de (bi)pyridinium comme catalyseurs pour la ROP de l’ε-caprolactone sont présentées. Un phénomène de coopérativité avec des bipyridiniums, dications donneurs de deux liaisons hydrogènes (IHBD) a été mis en évidence pour l’activation de l’ε-caprolactone, avec des activités en ROP plus importante en comparaison des systèmes impliquant la participation d’une seule liaison H. Les meilleurs systèmes ont pu être évalués plus en détail et ont permis d’accéder à des polymères de masses définies allant jusqu’à 13 000 g/mol<br>This PhD thesis is based on a joint between Sanofi in Vitry-sur-Seine and LHFA. This work consists in the development of new nanovectors based on biodegradable and biocompatible polymerics conjugate that enable to encapsulate, transport and deliver therapeutic agents. Previous works in the laboratory have shown that the release of hydrophobic drugs, such as Cabazitaxel, a taxane derivative, could be controlled by the architecture of the conjugated PEG-PLA. In the first chapter, a study was realized to improve the release kinetics of the drug, taking advantage of the difference of pH between healthy and cancerous tissue. Different linkers (linking the drug to the copolymer) having a pH dependent behavior have been studied, such as hydrazone, acetal and β-thiopropionate. The boronic ester bonding, dynamic function of pH, was also studied in order to destroy the NP and indirectly improve the release of drug. The synthesis and the evaluation of various conjugates have shown that the amphiphilic polymeric structure of the conjugates significantly inhibited the expected pH-dependent behavior. In the second chapter, several technologies such as targeting or imaging were studied. The influence of the Y and L-shape on the recognition and imaging properties was analyzed. The Y-shape offers advantages like the amount of ligand required for optimal active targeting and better visualization, in comparison with the results obtained with the L conjugates. The method of co-nanoformulation allowed to adjust the ligand amount or imaging probe within the NPs. In the third chapter, the synthesis and efficiency of (bi)pyridinium salts as catalysts for the ROP of ε-caprolactone are presented. A collaborative behavior with dication bipyridiniums is bearing two hydrogen bonds (IHBD) was demonstrated for the activation of the ε-caprolactone, with greater ROP activities compared to systems involving the participation of only one H bond. The best systems were evaluated in more details and allowed access to polymers with a molecular weight of up to 13 000 g / mol
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Breche, Quentin. "Copolymères triblocs biodégradables PLA-b-PEG-b-PLA pour ingénierie tissulaire : Caractérisation et modélisation de l'évolution de leurs propriétés mécaniques au cours de leur dégradation par hydrolyse." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAI068/document.
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L’ingénierie tissulaire est une méthode de reconstruction d’organes et de tissus vivants. Elle consiste à ensemencer et faire coloniser un implant spécifique appelé scaffold par des cellules. Ce scaffold est un matériau architecturé doté d’une géométrie adaptée à l’organe à reconstruire. Sa fonction est de servir de guide et de support de régénération au tissu. Afin d’éviter les conséquences à long terme de la présence d’un implant synthétique dans l’organisme (risque de rejet, inflammation ...) l’idéal est d’utiliser un matériau biorésorbable qui, se dégradant au fur et à mesure de la reconstruction, laisse place aux néo-tissus formés. Les polymères biorésorbables sont, grâce à la vaste gamme de propriétés qu’ils proposent, les meilleurs candidats pour ce genre d’applications. Un polymère biorésorbable particulièrement intéressant est le PLA-b-PEG-b-PLA. En effet, celui-ci est biocompatible et possède, par sa structure tribloc, une potentielle vaste gamme de propriétés physiques et mécaniques. La réussite de la reconstruction tissulaire nécessite une parfaite connaissance du comportement mécanique du matériau constituant le scaffold ainsi que son évolution au cours de la dégradation.L’objectif de cette thèse est la caractérisation expérimentale et la modélisation du comportement mécanique des polymères PLA-b-PEG-b-PLA au cours de leur dégradation. L’intérêt est de fournir des outils de dimensionnement de scaffolds biorésorbables pour l’ingénierie tissulaire. Dans un premier temps, des essais de traction-relaxation ont été conduits sur un PLA-b-PEG-b-PLA à différents temps de dégradation. Afin de réaliser ces essais dans des conditions proches de celles rencontrées in vivo, un dispositif expérimental permettant d’accomplir des essais mécaniques en milieu immergé à une température de 37°C a été mis au point. A partir de ces essais, un modèle viscoélastique linéaire capable de prendre en compte la variation des propriétés mécaniques au cours de la dégradation pour de faibles déformations a été réalisé. Dans un second temps, afin de modéliser le comportement mécanique dans une gamme plus large de déformations, un modèle viscoélastique non-linéaire a été développé. Il s’agit d’un modèle quasi-linéaire viscoélastique adaptatif capable de prédire les courbes de traction-relaxation à différents niveaux de déformation ainsi que la perte de propriétés mécaniques au cours de la dégradation. Lors de la troisième partie, des PLA-b-PEG-b-PLA de compositions et masses molaires différentes ont été caractérisés afin d’étudier l’influence de la structure originelle du polymère sur leurs propriétés mécaniques et leur évolution au cours de la dégradation. La capacité du modèle viscoélastique linéaire précédemment développé à prédire le comportement des différents polymères a alors été discutée. Dans une dernière partie, le modèle viscoélastique linéaire dégradable a été utilisé pour simuler numériquement le comportement mécanique d’un tricot potentiellement utilisable en ingénierie tissulaire<br>Tissue engineering is an interdisciplinary field that applies the principles of engineering and biological science toward the development of biological substitutes that restore, maintain or improve the development of a whole organ by tissue reconstruction. It consists in seeding an implant called scaffold with cells taken from the patient and cultivated in vitro. The cells will then colonize and recreate tissue that takes the shape of the scaffold. The scaffold is an architecture biomaterial specifically designed for a considered organ. The knowledge of mechanical properties of the scaffold is particularly important. Indeed, it often must be used as a mechanical substitute to the injured organ. Moreover, its mechanical properties must be compatible with those of the host tissue to allow a good tissue regeneration. The main advantage of using biodegradable materials is their degradation along the regeneration process. It means that the material no longer remains in the body at long term avoiding toxicity and inflammation risks. Among biodegradable materials, polymers are particularly interesting due to their large range of properties. A very good candidate for tissue engineering applications is the PLA-b-PEG-b-PLA biodegradable triblock copolymer. This polymer is biocompatible and possesses a good properties modulation. To allow a good tissue reconstruction, the knowledge of the mechanical properties of the scaffold as well as their evolution during degradation is essential.The aim of this work is to characterize experimentally and model the mechanical behavior of the PLA-b-PEG-b-PLA and its evolution during degradation. The interest is to provide tools to size and simulate biodegradable scaffolds for tissue engineering applications. At first, tensile-relaxation tests has been realized on the polymer during different degradation times. In order to realize the mechanical tests in conditions closed to in vivo ones, a specific experimental device has been designed that allows From this tests, a linear viscoelastic model able to take into account the variations of mechanical properties during degradation for small strain has been developed. Then, in order to model the mechanical behavior in a larger range of strain, a non-linear viscoelastic model was realized. In a third part, different polymers PLA-b-PEG-b-PLA with different initial composition has been mechanically characterized in order to study the influence of the original structure on mechanical properties and their evolution during degradation. To finish, the degradable linear viscoelastic model will be used to simulate numerically the mechanical behavior of a knitted textile for potential applications in tissue engineering
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Barbosa, Mariangela de Araujo. "Desenvolvimento e avaliação antimicrobiana “in vitro” de nanofibras de PLA/PEG com Terpinen-4-OL e clorexidina contra aggregatibacter actinomycetemcomitans." Universidade Federal da Paraíba, 2016. http://tede.biblioteca.ufpb.br:8080/handle/tede/9096.
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Previous issue date: 2016-01-28<br>To determine the minimum inhibitory concentration (MIC) and minimum bactericidal
concentration (MBC) of terpinen-4-ol and chlorhexidine produce and characterize
nanofibers PLA / PEG incorporated with terpinen-4-ol and chlorhexidine as well as
quantifying the viability biofilm mobile Aggregatibacter actinomycetemcomitans (Aa)
(ATCC 00078) grown on the surface of this inhibitory fiber. Methodology: The
determination of MIC and MBC was performed by broth microdilution; the nanofiber
terpinen-4-ol (40%) and chlorhexidine (0.12%) were produced by spinning blow solution
(SBS) and characterized by scanning electron microscopy (SEM), thermal gravimetric
analysis (TGA), calorimetry differential scanning (DSC) and infrared spectroscopy by
Fourier transform (FTIR). The cell was observed by fluorescence quantification and
nanofibers incorporated with chlorhexidine served as positive control for this assay.
Results: There was an effective antimicrobial activity terpinen-4-ol (MIC and MBC = 25
mg / mL) and chlorhexidine (MIC and MBC <15 mg / mL) on planktonic cells pa PEG
acted as a plasticizer resulting in a reduction in the crystallinity of the PLA, increased fiber
diameter and lightweight thermal destabilization of the material. The increase in PEG
concentration was not decisive for increasing the antimicrobial activity of the fibers but has
contributed to formation of a more amorphous material. The terpinen-4-ol fibers showed
similar antimicrobial activity to chlorhexidine fibers (p <0.05), and the Terpinen-4-ol fiber
with 20% PEG had best performance among your group. Conclusion: The terpinen-4-ol
and chlorhexidine had effective antimicrobial activity against A.A and SBS technique was
effective in the production of PLA nanofibers / PEG antimicrobial action against A.A
having the potential to drive future applications to combat periodontal disease.<br>Objetivo: Determinar a concentração inibitória mínima (CIM) e concentração bactericida
mínima (CBM) do terpinen-4-ol e clorexidina, produzir e caracterizar nanofibras de
PLA/PEG incorporadas com terpinen-4-ol e clorexidina, bem como e quantificar a
viabilidade celular de biofilme de Aggregatibacter actinomycetemcomitans (A.a.) (ATCC
00078) crescido sobre a superfície inibitória desta fibra. Metodologia: A determinação de
CIM e CBM foi realizada por microdiluição em caldo; as nanofibras de terpinen-4-ol
(40%) e clorexidina (0,12%) foram produzidas através da fiação por sopro em solução
(SBS) e caracterizadas por microscopia eletrônica de varredura (MEV), análise
termogravimétrica (TGA), calorimetria exploratória diferencial (DSC) e espectrometria no
infravermelho por transformada de Fourrier (FTIR). A quantificação celular foi verificada
por fluorescência e as nanofibras incorporadas com a clorexidina serviam de controle
positivo para este teste. Resultados: Observou-se uma efetiva atividade antimicrobiana do
terpinen-4-ol (CIM e CBM = 25 μg/mL) e da clorexidina (CIM e CBM < 15 μg/mL) sobre
células planctônicas de A.a. O PEG agiu como agente plastificante proporcionando
redução na cristalinidade do PLA, aumento do diâmetro das fibras e leve desestabilização
térmica do material. O aumento da concentração do PEG não foi determinante para o
aumento da atividade antimicrobiana das fibras, embora tenha contribuído para formação
de um material mais amorfo. As fibras de terpinen-4-ol apresentaram atividade
antimicrobiana semelhante às fibras de clorexidina (p<0,05), sendo a fibra Terpinen-4-ol
com 20% de PEG a que teve melhor desempenho dentre o seu grupo. Conclusão: O
terpinen-4-ol e a clorexidina apresentaram efetiva atividade antimicrobiana sobre A.a e a
técnica de SBS foi eficiente na produção de nanofibras de PLA/PEG com ação
antimicrobiana frente a A.a tendo potencial para conduzir futuras aplicações no combate às
doenças periodontais.
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Quijano, Rentería José Jhonatan. "Desarrollo de matrices porosas de ácido poliláctico (pla) y polietilenglicol (peg) mediante impresión 3d, aditivadas con quitosano y ácido úsnico para evaluar su liberación controlada." Master's thesis, Pontificia Universidad Católica del Perú, 2017. http://tesis.pucp.edu.pe/repositorio/handle/123456789/10047.
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Uno de los propósitos de la Ingeniería de Tejidos es reemplazar tanto a órganos como tejidos en el
cuerpo con materiales compatibles con el mismo. Destaca el uso de algunos materiales poliméricos,
biodegradables y biocompatibles, en el desarrollo de dispositivos que puedan transportar fármacos,
regenerar tejidos, sustituir funciones así como ofrecer aplicaciones y soluciones para problemas más
personalizados. Las matrices porosas poliméricas (Scaffolds) son sistemas de andamiaje temporales,
que buscan mejorar y poder dar tratamientos de regeneración más personalizados y de menor rechazo
que otros métodos convencionales. Entre los polímeros más utilizados en este campo de la ciencia se
tiene el ácido poliláctico (PLA), que es un termoplástico con propiedades adecuadas de
biocompatibilidad y biodegradación, de fácil procesamiento y modificación; otro polímero muy
usado es el polietilenglicol (PEG), debido a su afinidad biológica, a la proliferación de células y la no
degradación y degeneración de proteínas en presencia de este polímero.
El objetivo de este trabajo es desarrollar matrices porosas (scaffolds) fabricadas a partir de materiales
compuestos de ácido poliláctico (PLA) y polietilenglicol (PEG) mediante la técnica de modelado por
deposición fundida empleada en la impresión 3D, para luego aditivarlo con ácido úsnico y quitosano
y, por último, evaluar su liberación controlada en un medio determinado.
La metodología experimental utilizada para este fin fue la siguiente: inicialmente se fabricaron
filamentos de materiales compuestos de PLA/PEG con 0%, 5% y 10% de PEG en peso, en una
extrusora de doble husillo; luego se obtuvieron las matrices porosas mediante impresión 3D con
diferentes parámetros y porcentajes de relleno; seguidamente se realizó la aditivación del ácido úsnico
en las matrices porosas; asimismo, se recubrieron éstas con una película de quitosano, sumergiendo
la matriz polimérica en una solución al 1% de quitosano en ácido acético diluido, para luego evaluar
la liberación del fármaco en una solución tampón salina (buffer); los ensayos realizados para la
caracterización de las propiedades de las matrices poliméricas fueron: espectro infrarrojo de
transformada de Fourier (FTIR), calorimetría diferencial de barrido (DSC), termogravimetría (TGA),
microscopía óptica (SEM) y degradación en un medio acuoso; siguiendo en la mayoría las
recomendaciones y procedimientos propuestos en las normas ASTM y trabajos de referencia
anteriores a los mismos.
Como resultado, se obtuvieron las curvas de liberación controlada del fármaco en una solución
tampón salina en función del tiempo, determinándose que la liberación del fármaco para porcentajes
de relleno de 50% y 80% aumenta a mayores porcentajes de PEG, al mismo tiempo que se evidencia
una menor velocidad de liberación en presencia de la película de quitosano.<br>Tesis
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Villanueva, Tairo Alirio. "Desarrollo de armazones (scaffolds) a partir de poli (ácido láctico) (PLA) y polietilenglicol (PEG) utilizando la técnica de modelado por deposición fundida (FDM) empleada en impresión 3D." Master's thesis, Pontificia Universidad Católica del Perú, 2016. http://tesis.pucp.edu.pe/repositorio/handle/123456789/6912.
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El uso de los materiales poliméricos en el campo de la medicina ha demostrado un gran
avance durante los últimos años, buscando mejorar y ofrecer nuevos tratamientos de
rehabilitación más especializados. Un material muy utilizado hoy en día es el poli(ácido
láctico) (PLA) el cual es un polímero termoplástico con características limitadas como su
biocompatibilidad y biodegradación, por otro lado sus buenas propiedades mecánicas,
procesamiento y fácil modificación superan estas limitaciones convirtiéndolo en un
polímero con muchas posibilidades de desarrollo. Hoy en día este polímero es muy
utilizado para su investigación en el campo de los armazones (scaffolds). Los armazones
son estructuras temporales que promueven la reparación, regeneración de tejidos y órganos;
por tal razón se ha convertido en un tema de estudio actual e importante en el campo de
desarrollo de la ingeniería de tejidos y medicina regenerativa. De esta manera se plantea la
fabricación de armazones utilizando la técnica de modelado por deposición de fundido
(FDM) utilizado frecuentemente en la impresión 3D.
El objetivo del presente trabajo es el desarrollo de armazones (scaffolds) a partir de
poli (ácido láctico) (PLA) y polietilenglicol (PEG) utilizando la técnica de modelado por
deposición fundida empleada en impresión 3D.
Para el cumplimiento de los objetivos se utilizaron filamentos de PLA para fabricar
armazones de diversas características morfológicas según la metodología experimental, la
cual considera la evaluación de los valores y rangos de estudio de los diversos parámetros
de impresión en relación con el material utilizado. Los ensayos realizados para la
caracterización de las propiedades de los armazones fueron los siguientes: tracción,
compresión, calorimetría diferencial, microscopia estereoscópica y degradación. Siguiendo
en la mayoría las recomendaciones y procedimientos propuestos en las normas ASTM.
Se fabricaron armazones con poros interconectados de diferente morfología, con tamaños
de poro en el rango de 176 a 675 micras, resistencias a la tracción desde 8,33 MPa hasta
11,28 MPa, resistencias a la compresión desde 6,15 MPa hasta 15,17 MPa y porosidades
entre 56,12% a 63,3% además los valores descritos cumplen los requerimientos para su
potencial utilización como armazones para la reparación y regeneración de diversos tipos
de tejidos duros, como el hueso esponjoso, y blandos como el cartílago.<br>Tesis
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Lalloz, Faivre Augustine. "Administration de substances actives dans la peau : rôle de la composition hydrophile de nanoparticules polymériques." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1023/document.
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La conception de nanoparticules (NPs) polymériques pour le transport de médicaments dans la peau repose sur la compréhension du rôle de leurs compositions chimiques sur leurs interactions avec la peau, notamment la peau pathologique. Ce travail s'est attaché à définir le rôle de la composante hydrophile des NPs sur l'administration cutanée d'un principe actif lipophile modèle (cholécalciférol). Il a été remarqué que la composition hydrophile de polymères amphiphiles à base de PLA conditionnait les propriétés physicochimiques des NPs, notamment la taille, la surface, et la structure, tout comme la protection du cholécalciférol. Concernant l'absorption cutanée sur peau intacte, la composante hydrophile de NPs de 100 nm a eu peu d'influence. Une absorption cutanée du cholécalciférol légèrement plus importante a toutefois été obtenue à partir des NPs très riches en PEG hydrophile en comparaison aux NPs peu PEGylées. A l'inverse sur peau lésée, les NPs hydrophobes et négativement chargées de PLA seul ont permis la meilleure absorption du cholécalciférol. D'une part, la dynamique de la structure des NPs très PEGylées a permis une meilleure mouillabilité de la peau et une possible extraction de lipides cutanés, pouvant faciliter l'absorption sur peau intacte. D'autre part, la composition de la peau a conditionné la structure des NPs, puisque, sur peau lésée, les espèces ioniques libérées de la peau ont déstabilisé les NPs peu ou non PEGylées. Par adhésion à la surface de la peau, les agrégats de PLA ont pu ainsi faciliter l'absorption sur peau lésée.Lors du développement de formulations de NPs, leur composition chimique est donc à optimiser selon l'état pathologique de la peau<br>The design of clinically efficient polymeric nanoparticles (NPs) for skin drug delivery is based on the understanding of the influence of NPs chemical composition on their interactions with the skin tissue, notably the pathological skin. The aim of this work was to determine the influence of the hydrophilic component of polymeric NPs on the delivery of a lipophilic model drug (cholecalciferol).It was noticed that the polymeric hydrophilic composition of amphiphilic PLA-based NPs conditioned the NPs physico-chemical properties, notably in terms of size, surface properties, structure and drug protection. With regard to absorption into intact skin, the hydrophilic composition of 100 nm NPs had little impact. Only a slightly greater skin absorption was obtained from NPs with high hydrophilic PEG content compared to weakly PEGylated NPs. On the contrary in impaired skin, hydrophobic and negatively charged non-PEGylated NPs (PLA NPs) provided the best drug absorption. On the one hand, the dynamic structure of highly PEGylated NPs providing better skin wettability and potential skin lipids extraction may have contributed for increased absorption in intact skin. On the other hand, skin condition altered the NPs structure since it was observed that a non-negligible quantity of ionic species was released from impaired skin, triggering the destabilization of weakly or non-PEGylated charged NPs. However, only PLA aggregates sedimented/adhered onto the skin surface, which could have facilitated absorption in impaired skin. The polymeric hydrophilic composition of NPs and the pathological skin condition are therefore essential points to consider when designing nanoformulations
Book chapters on the topic "PLA-PEG"
1
Hiemstra, Christine, Zhiyuan Zhong, Pieter J. Dijkstra, and Jan Feijen. "Stereocomplexed PEG-PLA Hydrogels." In Hydrogels. Springer Milan, 2009. http://dx.doi.org/10.1007/978-88-470-1104-5_6.
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Nguyen, Hien Thi-Thanh, Van-Tien Bui, Anh Cam Ha, and Phu Dai Huynh. "Synthesis and Evaluation of Thermoresponsive PLA-PEG-PLA and pH/Temperature-Sensitive OS-PLA-PEG-PLA-OS Hydrogels as Injectable Drug Delivery Application." In IFMBE Proceedings. Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-75506-5_27.
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Otsuka, Hidenori, Yukio Nagasaki, and Kazunori Kataok. "Novel Approaches for the Construction of Functionalized PEG Layer on Surfaces Using Heterobifunctional PEG-PLA Block Copolymers and Their Micelles." In ACS Symposium Series. American Chemical Society, 2001. http://dx.doi.org/10.1021/bk-2000-0764.ch020.
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Parwez, Khalid, Arun A. Bhagwath, Asif Zawed, Bhagwan Rekadwad, and Suman V. Budihal. "Carbon Nanotubes Integrated Hydroxyapatite Nano-Composite for Orthopaedic and Tissue Engineering Applications." In Sol Gel and other Fabrication Methods of Advanced Carbon Materials [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.97428.
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The reassessment of the literature stipulates that an increasing amount of research in exploring the Hydroxyapatite Carbon Nanotubes (HA-CNT) system for orthopedic application. Chemical precipitation, CNT functionalization, and spray drying are the routinely used methods for CNT dispersal in HA matrix for the application such as bone tissue engineering, nanostructured scaffolds, dental regeneration, myocardial regeneration, and skin regeneration. Although mechanical strength and biocompatibility is a substantial concern for the fabrication of structures. Developing composite and bioceramic scaffolding with different natural and synthetic biomaterials are the futuristic approach in the biomedical engineering field. The problems such as biocompatibility, biodegradability, and mechanical resistance can be solved by combining natural, and artificial biomaterials. The natural biomaterials, such as collagen, cellulose, chitosan, have a close resemblance to the natural extracellular matrix (ECM). These materials are biocompatible, biodegradable. The artificial biomaterials, such as Poly Vinyl Pyrrolidone (PVP), Poly Capro Lactone (PCL), Poly Ethylene Glycol (PEG), and Poly Lactic Acid (PLA) are also the material of choice for the fabrication of the composite materials. Additional effort is necessary to fabricate biocompatible composite scaffolding for tissue engineering. Moreover, vascularization, differentiation, cellular proliferation, and cells to scaffold interaction are the foremost challenges in the area of tissue engineering that remains to overcome.
Conference papers on the topic "PLA-PEG"
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Pungkham, H., N. Swatdipakdi, M. Theerasilp, et al. "PEG-b-PCL and PEG-b-PLA polymeric micelles as nanocarrieres for lamellarin N delivery." In 2011 33rd Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE, 2011. http://dx.doi.org/10.1109/iembs.2011.6090882.
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Anuar, H., H. Noor Azlina, A. B. K. Suzana, et al. "Effect of PEG on impact strength of PLA hybrid biocomposite." In 2012 IEEE Symposium on Business, Engineering and Industrial Applications (ISBEIA). IEEE, 2012. http://dx.doi.org/10.1109/isbeia.2012.6422930.
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Weigum, Shannon E., Melissa Sutton, Eugenia Barnes, Sarah Miller, and Tania Betancourt. "Targeting hepatocellular carcinoma with aptamer-functionalized PLGA/PLA-PEG nanoparticles." In SPIE NanoScience + Engineering, edited by Hooman Mohseni, Massoud H. Agahi, and Manijeh Razeghi. SPIE, 2014. http://dx.doi.org/10.1117/12.2062283.
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Mosanenzadeh, Shahrzad Ghaffari, Hani E. Naguib, Chul B. Park, and Noureddine Atalla. "Development of Bio-Based Foams With Improved Acoustic and Mechanical Performance." In ASME 2012 Noise Control and Acoustics Division Conference at InterNoise 2012. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/ncad2012-1262.
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Interest in noise control has been growing in recent years and efforts are under way to improve the acoustic performance of existing sound absorbers and also to replace the non-recyclable ones with environmentally friendly materials. Present study describes the research on fabrication, improvement of acoustic absorption and enhancement of mechanical strength of bio-based open-cell foams. Through this study, highly porous open-cell Polylactide (PLA) foams were fabricated by a new fabrication method combining particulate leaching technique and compression molding. Foamed structures were fabricated with PLA and Polyethylene glycol (PEG) with salt as the particulate. Pore size of the foam was controlled by salt particulates and higher interconnectivity was achieved by the co-continuous blending morphology of PLA matrix with water-soluble PEG. As a result of novel secondary porous structure, acoustic performance of PLA foams was successfully improved. One issue with application of bio-based open-cell foams is the weak structure. To improve mechanical characteristics of PLA foams, different polymer composites of PLA and Polyhydroxyalkanoate (PHA) were foamed and characterized in terms of acoustic performance, mechanical properties and foam morphology. Polymers used in this study are bio-based which is of great importance considering huge amount of foams used as acoustic absorbers in various industries.
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Matus, Maria Francisca, Iván Palomo, and Cristian Vilos. "COMPUTATIONAL STUDY OF HYBRID PLA-PEG NANOPARTICLES AS ANTIPLATELET DRUG CARRIERS." In MOL2NET 2018, International Conference on Multidisciplinary Sciences, 4th edition. MDPI, 2018. http://dx.doi.org/10.3390/mol2net-04-06008.
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Nonkrathok, W., N. Suppakarn, and T. Trongsatitkul. "Effects of PEG and MMT contents on mechanical, thermal, and shape memory properties of MMT/PEG/PLA nanocomposites." In THE SECOND MATERIALS RESEARCH SOCIETY OF THAILAND INTERNATIONAL CONFERENCE. AIP Publishing, 2020. http://dx.doi.org/10.1063/5.0023117.
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Hartman, Lauren K., Harshil D. Dhruv, Kyle T. Householder, et al. "Abstract 1329: Intravenous delivery of Erlotinib-loaded PLA-PEG nanoparticles for treatment of GB." In Proceedings: AACR 107th Annual Meeting 2016; April 16-20, 2016; New Orleans, LA. American Association for Cancer Research, 2016. http://dx.doi.org/10.1158/1538-7445.am2016-1329.
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KUČEROVÁ, Liliana, Zuzana KOLÁŘOVÁ RAŠKOVÁ, Jaroslav KOUSAL, et al. "POLYESTER URETHANE (PLA/PEG) POLYMER BASED FILMS PREPARED BY PLASMA ASSISTED VAPOUR THERMAL DEPOSITION." In NANOCON 2019. TANGER Ltd., 2020. http://dx.doi.org/10.37904/nanocon.2019.8693.
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