RESUMO
As an important enzyme, xylanase is widely used in the food, pulp, and textile industry. Different applications of xylanase warrant specific conditions including temperature and pH. This study aimed to carry out sodium alginate beads as carrier to immobilize previous reported mutated xylanase from Neocallimastix patriciarum which expressed in E. coli, the activity of immobilization of mutated xylanase was elevated about 4% at pH 6 and 13% at 62 °C. Moreover, the immobilized mutated xylanase retained a greater proportion of its activity than the wide type in thermostability. These properties suggested that the immobilization of mutated xylanase has potential to apply in biobleaching industry.
Como importante enzima, a xilanase é amplamente utilizada na indústria alimentícia, de celulose e têxtil. Diferentes aplicações de xilanase garantem condições específicas, incluindo temperatura e pH. Este estudo teve como objetivo realizar grânulos de alginato de sódio como carreador para imobilizar xilanase mutada relatada anteriormente de Neocallimastix patriciarum que expressa em E. coli, a atividade de imobilização da xilanase mutada foi elevada em cerca de 4% em pH 6 e 13% a 62 °C. Além disso, a xilanase mutada imobilizada reteve uma proporção maior de sua atividade do que o tipo amplo em termoestabilidade. Essas propriedades sugerem que a imobilização da xilanase mutada tem potencial para aplicação na indústria de biobranqueamento.
Assuntos
Alginatos/farmacocinética , Neocallimastix , Xilanos/análiseRESUMO
As an important enzyme, xylanase is widely used in the food, pulp, and textile industry. Different applications of xylanase warrant specific conditions including temperature and pH. This study aimed to carry out sodium alginate beads as carrier to immobilize previous reported mutated xylanase from Neocallimastix patriciarum which expressed in E. coli, the activity of immobilization of mutated xylanase was elevated about 4% at pH 6 and 13% at 62 °C. Moreover, the immobilized mutated xylanase retained a greater proportion of its activity than the wide type in thermostability. These properties suggested that the immobilization of mutated xylanase has potential to apply in biobleaching industry.(AU)
Como importante enzima, a xilanase é amplamente utilizada na indústria alimentícia, de celulose e têxtil. Diferentes aplicações de xilanase garantem condições específicas, incluindo temperatura e pH. Este estudo teve como objetivo realizar grânulos de alginato de sódio como carreador para imobilizar xilanase mutada relatada anteriormente de Neocallimastix patriciarum que expressa em E. coli, a atividade de imobilização da xilanase mutada foi elevada em cerca de 4% em pH 6 e 13% a 62 °C. Além disso, a xilanase mutada imobilizada reteve uma proporção maior de sua atividade do que o tipo amplo em termoestabilidade. Essas propriedades sugerem que a imobilização da xilanase mutada tem potencial para aplicação na indústria de biobranqueamento.(AU)
Assuntos
Neocallimastix , Alginatos/farmacocinética , Xilanos/análiseRESUMO
The aim of this study was to design a nanocarrier system for inhalation delivery of rifampicin (RIF) in combination with ascorbic acid (ASC), namely constituted of sodium alginate coated with chitosan and Tween 80 (RIF/ASC NPs) as a platform for the treatment of pulmonary tuberculosis infection. A Box-Behnken experimental design and response surface methodology (RSM) were applied to elucidate and evaluate the effects of several factors on the nanoparticle properties. On the other hand, it was found that RIF/ASC NPs were less cytotoxic than the free RIF, showing a significantly improved activity against nine clinical strains of Mycobacterium tuberculosis (M. tb) in comparison with the free drug. RIF/ASC NPs had an average particle size of 324.0 ± 40.7 nm, a polydispersity index of 0.226 ± 0.030, and a zeta potential of - 28.52 ± 0.47 mV and the surface was hydrophilic. The addition of sucrose (1% w/v) to the nanosuspension resulted in the formation of a solid pellet easily redispersible after lyophilization. RIF/ASC NPs were found to be stable at different physiological pH values. In summary, findings of this work highlight the potential of the RIF/ASC NP-based formulation development herein to deliver RIF in combination with ASC through pulmonary route by exploring a non-invasive route of administration of this antibiotic, increasing the local drug concentrations in lung tissues, the primary infection site, as well as reducing the risk of systemic toxicity and hence improving the patient compliance.
Assuntos
Alginatos/administração & dosagem , Ácido Ascórbico/administração & dosagem , Quitosana/administração & dosagem , Mycobacterium tuberculosis/efeitos dos fármacos , Nanopartículas/administração & dosagem , Rifampina/administração & dosagem , Alginatos/química , Alginatos/farmacocinética , Animais , Antibióticos Antituberculose/administração & dosagem , Antibióticos Antituberculose/química , Antibióticos Antituberculose/farmacocinética , Ácido Ascórbico/química , Ácido Ascórbico/farmacocinética , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Quitosana/química , Quitosana/farmacocinética , Chlorocebus aethiops , Relação Dose-Resposta a Droga , Portadores de Fármacos/administração & dosagem , Portadores de Fármacos/química , Portadores de Fármacos/metabolismo , Sistemas de Liberação de Medicamentos/métodos , Humanos , Mycobacterium tuberculosis/metabolismo , Nanopartículas/química , Nanopartículas/metabolismo , Tamanho da Partícula , Rifampina/química , Rifampina/farmacocinética , Células VeroRESUMO
Oral insulin administration is limited due to its degradation by proteases. The hormone was encapsulated in spheres made of either pure calcium alginate (ALG) or its association with whey protein isolate (WPI-ALG) in order to minimise loss in the stomach region while allowing liberation in the maximum absorption area, located in the intestine. Diffusion coefficients for both matrix compositions were determined in vitro for gastric pH (5.88 and 10.26 × 10-12 m2 s-1) and intestinal pH (21.11 and 79.29 × 10-12 m2 s-1). Higher initial insulin concentrations and lower diameters accelerated its release, confirming Fickian behaviour. The analytic model exhibited a good fit in most cases. Computer simulations revealed that ALG spheres are more convenient for oral administration because they release more insulin in the intestine than the WPI-ALG ones, thus supporting its therapeutic viability for the purpose of reducing stress in those who depend on insulin.
Assuntos
Alginatos , Diabetes Mellitus/tratamento farmacológico , Insulina , Microesferas , Proteínas do Soro do Leite , Administração Oral , Alginatos/química , Alginatos/farmacocinética , Alginatos/farmacologia , Preparações de Ação Retardada/química , Preparações de Ação Retardada/farmacocinética , Preparações de Ação Retardada/farmacologia , Ácido Glucurônico/química , Ácido Glucurônico/farmacocinética , Ácido Glucurônico/farmacologia , Ácidos Hexurônicos/química , Ácidos Hexurônicos/farmacocinética , Ácidos Hexurônicos/farmacologia , Humanos , Concentração de Íons de Hidrogênio , Insulina/química , Insulina/farmacocinética , Insulina/farmacologia , Proteínas do Soro do Leite/química , Proteínas do Soro do Leite/farmacocinética , Proteínas do Soro do Leite/farmacologiaRESUMO
Biomaterials conceived for vectorization of bioactives are currently considered for biomedical, biological, and environmental applications. We have produced a pH-sensitive biomaterial composed of natural source alginate and chitosan polysaccharides for application as a drug delivery system via oral administration. The composite particle preparation was in situ monitored by means of isothermal titration calorimetry. The strong interaction established between the macromolecules during particle assembly led to 0.60 alginate/chitosan effective binding sites with an intense exothermic effect and negative enthalpy variation on the order of a thousand kcal/mol. In the presence of model drugs mebendazole and ivermectin, with relatively small and large structures, respectively, mebendazole reduced the amount of chitosan monomers available to interact with alginate by 27%, which was not observed for ivermectin. Nevertheless, a state of intense negative Gibbs energy and large entropic decrease was achieved, providing evidence that formation of particles is thermodynamically driven and favored. Small-angle X-ray scattering provided further evidence of similar surface aspects independent of the presence of drug. The physical responses of the particles to pH variation comprise partial hydration, swelling, and the predominance of positive surface charge in strong acid medium, whereas ionization followed by deprotonation leads to compaction and charge reversal rather than new swelling in mild and slightly acidic mediums, respectively. In vivo performance was evaluated in the treatment of endoparasites in Corydoras fish. Systematically with a daily base oral administration, particles significantly reduced the infections over 15 days of treatment. The experiments provide evidence that utilizing particles granted and boosted the action of the antiparasitic drugs, leading to substantial reduction or elimination of infection. Hence, the pH-responsive particles represent a biomaterial with prominent characteristics that is promising for the development of targeted oral drug delivery.
Assuntos
Materiais Biocompatíveis , Peixes-Gato/parasitologia , Doenças dos Peixes , Ivermectina , Mebendazol , Doenças Parasitárias/tratamento farmacológico , Alginatos/química , Alginatos/farmacocinética , Alginatos/farmacologia , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacocinética , Materiais Biocompatíveis/farmacologia , Quitosana/química , Quitosana/farmacocinética , Quitosana/farmacologia , Preparações de Ação Retardada/química , Preparações de Ação Retardada/farmacocinética , Preparações de Ação Retardada/farmacologia , Doenças dos Peixes/tratamento farmacológico , Doenças dos Peixes/parasitologia , Ácido Glucurônico/química , Ácido Glucurônico/farmacocinética , Ácido Glucurônico/farmacologia , Ácidos Hexurônicos/química , Ácidos Hexurônicos/farmacocinética , Ácidos Hexurônicos/farmacologia , Concentração de Íons de Hidrogênio , Ivermectina/química , Ivermectina/farmacocinética , Ivermectina/farmacologia , Mebendazol/química , Mebendazol/farmacocinética , Mebendazol/farmacologiaRESUMO
The current study developed through layer-by-layer deposition a multilayer membrane for intraoral drug delivery and analyzed the biochemical, functional, and biological properties of this membrane. For that purpose, we designed a three-layer chlorhexidine-incorporated membrane composed by pure chitosan and alginate. The biochemical, functional, and biological properties were analyzed by the following tests: degradation in saliva medium; controlled drug release; water absorption, mass loss; pH analysis; and biocompatibility through fibroblast cell viability by MTT assay. All tests were conducted at three different periods (24, 48 and 72hours). The results demonstrated that hybrid membranes composed by alginate and chitosan with glycerol had greater water absorption and mass loss in buffer solution and in artificial saliva. The controlled drug release test revealed that the hybrid membrane exhibited greater drug release (0.075%). All chlorhexidine-incorporated membranes reduced the cell viability, and chitosan membranes with and without glycerol did not interfere with fibroblast viability. The biochemical and biophysical characteristics of the designed membranes and the findings of cell viability tests indicate great potential for application in Dentistry.
Assuntos
Alginatos , Quitosana , Clorexidina , Portadores de Fármacos , Membranas Artificiais , Alginatos/química , Alginatos/farmacocinética , Alginatos/farmacologia , Animais , Quitosana/química , Quitosana/farmacocinética , Quitosana/farmacologia , Clorexidina/química , Clorexidina/farmacocinética , Clorexidina/farmacologia , Preparações de Ação Retardada/química , Preparações de Ação Retardada/farmacocinética , Preparações de Ação Retardada/farmacologia , Odontologia , Portadores de Fármacos/química , Portadores de Fármacos/farmacocinética , Portadores de Fármacos/farmacologia , Ácido Glucurônico/química , Ácido Glucurônico/farmacocinética , Ácido Glucurônico/farmacologia , Ácidos Hexurônicos/química , Ácidos Hexurônicos/farmacocinética , Ácidos Hexurônicos/farmacologia , Camundongos , Células NIH 3T3RESUMO
This paper reports on a study of the influence of sodium alginate concentration and iron addition on the ion exchange kinetics of calcium alginate ferrogel beads produced by external gelation. The calcium absorption and sodium release of the beads were fitted to Fick's second law for unsteady state diffusion in order to obtain the effective diffusion coefficients of Na(+) and Ca(2+). The dried beads were characterized concerning their thermal stability, particle size distribution and morphology. The gelation kinetics showed that an increase in alginate concentration from 1% to 2% increased the Ca(2+) equilibrium concentration, but presented no effect on Ca(2+) effective diffusion coefficient. Alginate concentration higher than 2% promoted saturation of binding sites at the bead surfaces. The addition of iron promoted faster diffusion of Ca(2+) inside the gel beads and reduced the Ca(2+) equilibrium concentration. Also, iron particles entrapped in the alginate gel beads promoted greater absorption of water compared to pure alginate gel and lower thermal stability of the beads. The main diffusion of Ca(2+) into and Na(+) out from the bead took place during the first 60 min, during which almost 85-90% of the Ca(2+) equilibrium concentration is achieved, indicating that this period is sufficient to produce a Ca-alginate bead with high crosslinking of the polymer network.
Assuntos
Alginatos/química , Troca Iônica , Fenômenos Magnéticos , Alginatos/farmacocinética , Cálcio/química , Ácido Glucurônico/química , Ácido Glucurônico/farmacocinética , Ácidos Hexurônicos/química , Ácidos Hexurônicos/farmacocinética , Ferro/química , Tamanho da Partícula , Polímeros/química , Sódio/química , Termogravimetria/métodosRESUMO
N-trimethyl chitosan of two quaternization degrees, DQ=20 and 80mol% and labeled as TMC20 and TMC80, were synthesized and characterized by (1)H NMR. Polyelectrolyte complexes (PECs) of TMC/alginate (TMC/ALG) were prepared at pHs 2, 7 and 10 by mixing the aqueous solutions of unlike polymers. The PECs were characterized through infrared spectroscopy (FTIR), thermogravimetric analysis (TGA/DTG) and wide-angle X-ray scattering (WAXS). Using the TMC of DQ=20 mol% and following the same methodology for preparing the PECs, beads of TMC20/ALG were obtained at pH 2 and loaded with curcumin (CUR) at pH 6.0-6.5. The morphology of the beads was evaluated by scanning electron microscopy (SEM). Studies in vitro of the controlled release of CUR from beads were investigated in simulated intestinal fluid (SIF) and simulated gastric fluid (SGF) and treated using conventional and partition-diffusion models. Results indicated that the beads based on TMC20 and ALG presented potential as drug-carrier to improve the solubility and biological activity of CUR at pH close to physiological one.
Assuntos
Alginatos , Quitosana , Curcumina , Alginatos/síntese química , Alginatos/química , Alginatos/farmacocinética , Alginatos/farmacologia , Quitosana/síntese química , Quitosana/química , Quitosana/farmacocinética , Curcumina/química , Curcumina/farmacocinética , Preparações de Ação Retardada/síntese química , Preparações de Ação Retardada/química , Preparações de Ação Retardada/farmacocinética , Ácido Glucurônico/síntese química , Ácido Glucurônico/química , Ácido Glucurônico/farmacocinética , Ácido Glucurônico/farmacologia , Ácidos Hexurônicos/síntese química , Ácidos Hexurônicos/química , Ácidos Hexurônicos/farmacocinética , Ácidos Hexurônicos/farmacologia , Concentração de Íons de HidrogênioRESUMO
The aim of the present work was to develop a programmed drug delivery system which would be able to release the drug after 6 h of lag time by use of hydrophilic polymers. The capsule body was made impermeable by use of formaldehyde vapor treatment, while the cap was untreated. The capsule was filled with two layered tablets (tablet-in-capsule), followed by a sodium bicarbonate:citric acid mixture (SBCM) and lactose as bulking agent. Sodium alginate, chitosan, HPMC K15 and chitosan:sodium alginate complex (CSAC) were used as the rate modulating layer. Through combined use of HPMC K15 and adjusting the ratio of CSAC, the desired lag time of 6 h was obtained. The effect of the bulking agents on the lag time were also studied and it was found that the lag time was decreased with higher amounts of lactose, and delayed dissolution and decreased lag time was observed at higher amount of effervescent mixture.
O objetivo do presente trabalho foi desenvolver sistema de liberação programada de cloridrato de verapamil capaz de liberação imediata do fármaco após 6 h de intervalo de tempo usando polímeros hidrofílicos. O corpo da cápsula foi impermeabilizado por tratamento de vapor de formaldeído, enquanto a tampa não foi submetida ao tratamento. Dois comprimidos foram inseridos na cápsula (comprimidos em cápsula) seguido de mistura de bicarbonato de sódio: ácido cítrico e lactose, utilizados como excipientes. O alginato de sódio, a quitosana, o HPMC K15 e o complexo quitosana:alginato de sódio foram utilizados para modular a razão de liberação do fármaco. A combinação entre o HPMC K15 e o ajuste da proporção do complexo quitosana:alginato de sódio permitiu a liberação do fármaco após 6 h. O efeito dos excipientes na liberação do fármaco foi também avaliado. Verificou-se que o tempo de latência foi reduzido na presença de maior quantidade de lactose, enquanto o menor tempo foi observado empregando maior concentração da mistura efervescente.
Assuntos
Comprimidos/análise , Verapamil/farmacocinética , Ritmo Circadiano , Quitosana/farmacocinética , Alginatos/farmacocinética , Lactose/classificaçãoRESUMO
The aim of this study was to assess chitosan: alginate capsules as gastric resistant systems for oral administration of insulin. Chitosan: alginate capsules ofi nsulin were tested in simulated gastric and intestinal media and in vivo. The capsules released only about 20% of the insulin after 60 minutes of incubation in simulated gastric medium. On the other hand, almost all the encapsulated insulin was released after being incubated for 90 min in simulated intestinal medium. When capsules containing 20 IU and 40 IU insulin were given to rats by gavage, signifi cantly reduced plasma glucose levels were observed (33.7 % and 51.7%, respectively) two hours after the treatment, which returned to normal after six hours. These results indicate that chitosan: alginate capsules are potential carriers for oral protein delivery.