Obtenção de microcápsulas do éster etílico do ácido docosa-hexaenoico (DHAEE) por atomização: otimização através de planejamento experimental

Docosahexaenoic acid is an essential polyunsaturated fatty acid with important metabolic activities. Its conjugated double bonds make it susceptible to decomposition. Its stability may be improved through fatty acid entrapment with a spray-drying technique; however, the many parameters involved in this technique must be considered to avoid affecting the final product quality. Therefore, this study aimed to evaluate the entrapment conditions and yields of fish oil enriched with docosahexaenoic acid ethyl ester. Microcapsules were obtained from Acacia gum using a spray-drying technique. The experimental samples were analyzed by chromatography and delineated by Statistica software, which found the following optimum entrapment conditions: an inlet temperature of 188 °C; 30% core material; an N2 flow rate of 55 mm; and a pump flow rate of 12.5 mL/minute. These conditions provided a 66% yield of docosahexaenoic acid ethyl ester in the oil, corresponding to 19.8% of entrapped docosahexaenoic acid ethyl ester (w/w). This result was considered significant since 30% corresponded to wall material.O ácido docoso-hexaenoico é um ácido graxo poli-insaturado essencial que desempenha importantes ações metabólicas. Entretanto, por possuir duplas ligações conjugadas torna-se suscetível à decomposição. Uma das formas de minimizar esta possível decomposição é o emprego da técnica de atomização para microencapsulação. Porém, esta técnica envolve uma série de parâmetros de processo, que podem vir a alterar a qualidade do produto final. Assim, o objetivo deste trabalho foi microencapsular óleo de peixe enriquecido no éster etílico do ácido docoso-hexaenoico (DHAEE-85%), variando condições operacionais e avaliar o rendimento pela análise por cromatografia gasosa, após extração das microcápsulas. Para tanto, foi utilizado o processo de microencapsulação por atomização e o agente encapsulante foi a goma arábica. A avaliação cromatográfica de vários experimentos delineados pelo software Statistica, mostrou que os pontos ótimos para obtenção das microcápsulas de DHAEE foram: temperatura de entrada 188 °C, porcentagem de recheio 30%, vazão de nitrogênio 55 mm N2 e vazão da bomba de 12,5 mL/minuto. Estas condições de processo foram testadas experimentalmente, resultando no teor de 66% m/m de DHAEE no óleo extraído, valor correspondente a 19,8% m/m de DHAEE encapsulado, valor considerado satisfatório uma vez que 30% das microcápsulas correspondiam teoricamente ao material de parede.589596Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Influence of the incorporation of the antimicrobial agent polyhexamethylene biguanide on the properties of dense and porous chitosan-alginate membranes

This work is a continuation of a previous study which described the development of dense and porous chitosan-alginate polyelectrolyte complexes through the addition of different amounts of Pluronic F68 to the polymeric mixture. The present study consisted in the incorporation of an antimicrobial agent, polyhexamethylene biguanide (PHMB), to the previously developed system. PHMB was incorporated at 1 and 10% (w/w) with high incorporation efficiencies, varying from 72 to 86%. Release profiles in phosphate buffered saline were evaluated using the Korsmeyer-Peppas equation, which suggested a quasi-Fickian diffusion mechanism for all obtained formulations. The maximum release percentage was approximately 15% as a result from the high affinity between PHMB and the polysaccharides. The obtained polyelectrolyte complexes were able to prevent the growth of both Staphylococcus aureus and Pseudomonas aeruginosa on their surfaces, being considered potentially effective wound dressings93671678CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP308871/2012-0; 307139/2015-83665/20142009/1775-

Prolonged Antibacterial Activity in Tannic Acid–Iron Complexed Chitosan Films for Medical Device Applications

Healthcare-associated infections (HAIs) represent a global burden, leading to significant mortality and generating financial costs. One important cause of HAIs is the microbiological contamination of implantable medical devices. In this context, a novel antimicrobial drug-eluting system, based on chitosan and loaded with gentamicin, a broad-spectrum antibiotic, was developed. The effects of the addition of tannic acid and different FeSO4 concentrations on the loaded antibiotic release were evaluated. The properties of the films were assessed in terms of thickness, swelling, mass loss and wettability. The films’ surface composition was characterized by X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy. The antibiotic release in phosphate buffer saline was quantified by high-performance liquid chromatography–mass spectrometry, and the antibacterial activity was evaluated. Hemolysis and cytotoxicity were also assessed. The results showed that the addition of tannic acid and iron decreased the swelling degree and degradation due to strong interactions between the different components, thus impacting gentamicin release for up to 35 days. In conclusion, this study presents a novel strategy to produce low-cost and biocompatible antimicrobial drug-eluting systems with sustained and prolonged antibacterial activity over more than a month

Effects of supercritical carbon dioxide processing on the properties of chitosan–alginate membranes

Chitosan–alginate membranes with different porosities designed to be used as wound dressings or scaffolds were processed in supercritical CO2 (scCO2) with the aim of improving their physicochemical properties. The membranes were characterized before and after processing at 100 or 300 bar and 45 °C for 2 h with a depressurization rate of 5 bar/min. The results show that after processing, thickness, real density and porosity increased up to 68%, 100% and 167%, respectively, and surface area decreased up to 47%. Because of changes in structure, water vapor sorption and permeability increased up to 53% and 84%, respectively. Stabilization of the chitosan–alginate complex was noticed after processing with scCO2 according to thermal analysis. The results indicate that supercritical CO2 processing made the membranes more adequate for use as wound dressings112128135CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPsem informaçã

Control of the properties of porous chitosan - alginate membranes through the addition of different proportions of Pluronic F68

This work addresses the development and characterization of porous chitosan–alginate based polyelectrolyte complexes, obtained by using two different proportions of the biocompatible surfactant Pluronic F68. These biomaterials are proposed for applications as biodegradable and biocompatible wound dressing and/or scaffolds. The results indicate that thickness, roughness, porosity and liquid uptake of the membranes increase with the amount of surfactant used, while their mechanical properties and stability in aqueous media decrease. Other important properties such as color and surface hydrophilicity (water contact angle) are not significantly altered or did not present a clear tendency of variation with the increase of the amount of surfactant added to the polyelectrolyte complexes, such as real density, average pore diameter, total pore volume and surface area. The prepared biomaterials were not cytotoxic to L929 cells. In conclusion, it is possible to tune the physicochemical properties of chitosan–alginate polyelectrolyte complexes, through the variation of the proportion of surfactant (Pluronic F68) added to the mixture, so as to enable the desired application of these biomaterials44117125CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP308871/2012-0288/112009/17755-

Control of the properties of porous chitosan-alginate membranes through the addition of different proportions of Pluronic F68

This work addresses the development and characterization of porous chitosan-alginate based polyelectrolyte complexes, obtained by using two different proportions of the biocompatible surfactant Pluronic F68. These biomaterials are proposed for applications as biodegradable and biocompatible wound dressing and/or scaffolds. The results indicate that thickness, roughness, porosity and liquid uptake of the membranes increase with the amount of surfactant used, while their mechanical properties and stability in aqueous media decrease. Other important properties such as color and surface hydrophilicity (water contact angle) are not significantly altered or did not present a clear tendency of variation with the increase of the amount of surfactant added to the polyelectrolyte complexes, such as real density, average pore diameter, total pore volume and surface area. The prepared biomaterials were not cytotoxic to L929 cells. In conclusion, it is possible to tune the physicochemical properties of chitosan-alginate polyelectrolyte complexes, through the variation of the proportion of surfactant (Pluronic F68) added to the mixture, so as to enable the desired application of these biomaterials

Chitosan‐alginate membranes accelerate wound healing

The purpose of this study was to evaluate the efficacy of chitosan‐alginate membrane to accelerate wound healing in experimental cutaneous wounds. Two wounds were performed in Wistar rats by punching (1.5 cm diameter), treated with membranes moistened with saline solution (CAM group) or with saline only (SL group). After 2, 7, 14, and 21 days of surgery, five rats of each group were euthanized and reepithelialization was evaluated. The wounds/scars were harvested for histological, flow cytometry, neutrophil infiltrate, and hydroxyproline analysis. CAM group presented higher inflammatory cells recruitment as compared to SL group on 2nd day. On the 7th day, CAM group showed higher CD11b+ level and lower of neutrophils than SL group. The CAM group presented higher CD4+ cells influx than SL group on 2nd day, but it decreased during the follow up and became lower on 14th and 21st days. Higher fibroplasia was noticed on days 7 and 14 as well as higher collagenesis on 21st in the CAM group in comparison to SL group. CAM group showed faster reepithelialization on 7th day than SL group, although similar in other days. In conclusion, chitosan‐alginate membrane modulated the inflammatory phase, stimulated fibroplasia and collagenesis, accelerating wound healing process in rats103510131022COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPsem informaçã

Chitosan-alginate membranes accelerate wound healing

The purpose of this study was to evaluate the efficacy of chitosan-alginate membrane to accelerate wound healing in experimental cutaneous wounds. Two wounds were performed in Wistar rats by punching (1.5 cm diameter), treated with membranes moistened with saline solution (CAM group) or with saline only (SL group). After 2, 7, 14, and 21 days of surgery, five rats of each group were euthanized and reepithelialization was evaluated. The wounds/scars were harvested for histological, flow cytometry, neutrophil infiltrate, and hydroxyproline analysis. CAM group presented higher inflammatory cells recruitment as compared to SL group on 2(nd) day. On the 7(th) day, CAM group showed higher CD11b(+) level and lower of neutrophils than SL group. The CAM group presented higher CD4(+) cells influx than SL group on 2(nd) day, but it decreased during the follow up and became lower on 14(th) and 21(st) days. Higher fibroplasia was noticed on days 7 and 14 as well as higher collagenesis on 21(st) in the CAM group in comparison to SL group. CAM group showed faster reepithelialization on 7(th) day than SL group, although similar in other days. In conclusion, chitosan-alginate membrane modulated the inflammatory phase, stimulated fibroplasia and collagenesis, accelerating wound healing process in rats. (c) 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 103B: 1013-1022, 2015.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP