RESUMO
Phosphate chelators are frequently used in patients with chronic kidney disease (CKD). New iron-based chelators remain understudied and offer a promising therapeutic option for the control of bone and mineral disorders of chronic kidney disease (BMD-CKD). We assessed the effect of the phosphorus chelator, chitosan-iron III (CH-FeCl), compared to calcium carbonate (CaCO3) in BMD-CKD and the potential iron overload in uremic rats. Thirty-two animals were divided into four groups, namely the control, CKD, CKD/CH-FeCl, and CKD/CaCO3 groups. CKD was induced by adding 0.75% (4 weeks) and 0.1% (3 weeks) adenine to the diet. The chelators were administered from week 3 through week 7. The renal function, BMD-CKD markers, and histomorphometry of the femur were assessed at week 7. The CKD group showed a significant increase in creatinine (83.9 ± 18.6 vs. 41.5 ± 22.1 µmol/L; P = 0.001), phosphate (3.5 ± 0.8 vs. 2.2 ± 0.2 mmol/L; P = 0.001), fractional excretion of phosphorus (FEP) (0.71 ± 0.2 vs. 0.2 ± 0.17; P = 0.0001), and FGF23 (81.36 ± 37.16 pg/mL vs. 7.42 ± 1.96; P = 0.011) compared to the control group. There was no accumulation of serum or bone iron after the use of CH-FeCl. The use of chelators reduced the FEP (control: 0.71 ± 0.20; CKD/CH-FeCl: 0.40 ± 0.16; CKD/CaCO3 0.34 ± 0.15; P = 0.001), without changes in the serum FGF23 and parathyroid hormone levels. Histomorphometry revealed the presence of bone disease with high remodeling in the uremic animals without changes with the use of chelators. The CH-FeCl chelator was efficient in reducing the FEP without iron accumulation, thereby paving the way for the use of this class of chelators in clinical settings in the future.
Assuntos
Osso e Ossos , Quelantes , Fósforo , Insuficiência Renal Crônica , Animais , Osso e Ossos/metabolismo , Quelantes/farmacologia , Fatores de Crescimento de Fibroblastos , Ferro/metabolismo , Hormônio Paratireóideo , Fosfatos/metabolismo , Fósforo/metabolismo , Ratos , Insuficiência Renal Crônica/tratamento farmacológico , Insuficiência Renal Crônica/metabolismoRESUMO
The purpose of this study was to synthesize a new magnetic material with antimicrobial properties, incorporated into a biopolymer and containing silver nanoparticles (Ag NP) prepared extract of Eugenia umbelliflora as a reducing agent. Silver nanoparticles incorporated into magnetic nanocomposite O-carboxymethylchitosan/y-Fe2O3/Ag0 (CMAgE) composite were synthesized using an extract of E. umbelliflora. The antimicrobial activity of the pathogenic microorganism is reported here. The synthesized nanoparticles were also characterized, and quantified by Ag analysis. The minimum inhibitory concentrations (MIC) of CMAgE against Staphylococcus aureus, Escherichia coli, and Candida albicans were 16.5, 1000 and 500 µg/mL, respectively. The results show that these materials have significant synergistic effect on each other. The potential phytotoxic effect of the nanocomposites was evaluated using Cucumis sativus seeds. The positive values for seedling elongation inhibition (SEI) show that CMAgE and methanol extract of Eugenia umbelliflora (Eug) cause growth inhibition at a concentration of 1000 mg/L. The germination index (GI) values of 40% and 80% at 1000 mg/L, for CMAgE and Eug, respectively, showed inhibition of germination. CMAgE and Eug showed cytotoxic effects against Artemia salina nauplii, with LC50 values of 72.5 µL/mL and < 5.0 µL/mL respectively, after 48 h.
Assuntos
Antibacterianos/farmacologia , Artemia/crescimento & desenvolvimento , Quitosana/análogos & derivados , Eugenia/química , Compostos Ferrosos/química , Nanopartículas Metálicas/administração & dosagem , Extratos Vegetais/farmacologia , Prata/química , Animais , Antibacterianos/química , Artemia/efeitos dos fármacos , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Quitosana/química , Nanopartículas Metálicas/química , Nanocompostos/administração & dosagem , Nanocompostos/químicaRESUMO
Magnetic silver nanoparticles (MNPAg) are interesting nanotechnology materials with borderless environmental science, that can be used to disinfect water contaminated with pathogenic bacteria. The use of MNPAg leads to increased risk of nanomaterial contamination in the environment, especially natural water sources, with harmful effects on the ecosystem. This study investigating survival and enzyme activity of magnetic O-carboxymethylchitosan loaded silver nanoparticle on Artemia salina. The results showed that mortality increased with increasing concentrations of MNPAg. O-Carboxymethylchitosan loaded silver nanoparticles were found to be more toxic, with a LC50 of 902.1 mg/L for γ-Fe2O3/Ag without reducing agent. Accumulation of silver on Artemia salina depends on the type of nanoparticle. Accumulation of nanoparticle containing polymers (carboxymethylchitosan/γ-Fe2O3/Ag without reducing agent, carboxymethylchitosan/γ-Fe2O3/Ag reduced with sucrose and carboxymethylchitosan/γ-Fe2O3/Ag reduced with NaBH4) were found to be higher than γ-Fe2O3/Ag reduced with NaBH4, γ-Fe2O3/Ag reduced with sucrose and γ-Fe2O3/Ag without reducing agent under the same experimental conditions. The antioxidant enzyme (CAT, SOD and GST) activities increased slightly following exposure, indicating that the toxic effects are related to oxidative stress. The combined results so far indicate that MNPA does not have the potential to affect aquatic organisms when released into the ecosystem.
Assuntos
Quitosana/análogos & derivados , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Artemia/fisiologia , Quitosana/toxicidadeRESUMO
Phosphate retention and hyperphosphataemia are associated with increased mortality in patients with chronic kidney disease (CKD). We tested the use of cross-linked iron chitosan III (CH-FeCl) as a potential phosphate chelator in rats with CKD. We evaluated 96 animals, divided equally into four groups (control, CKD, CH-FeCl and CKD/CH-FeCl), over 7 weeks. We induced CKD by feeding animals an adenine-enriched diet (0.75% in the first 4 weeks and 0.1% in the following 3 weeks). We administered 30 mg/kg daily of the test polymer, by gavage, from the third week until the end of the study. All animals received a diet supplemented with 1% phosphorus. Uraemia was confirmed by the increase in serum creatinine in week 4 (36.24 ± 18.56 versus 144.98 ± 22.1 µmol/L; p = 0.0001) and week 7 (41.55 ± 22.1 versus 83.98 ± 18.56 µmol/L; p = 0.001) in CKD animals. Rats from the CKD group treated with CH-FeCl had a 54.5% reduction in serum phosphate (6.10 ± 2.23 versus 2.78 ± 0.55 mmol/L) compared to a reduction of 25.6% in the untreated CKD group (4.75 ± 1.45 versus 3.52 ± 0.74 mmol/L, p = 0.021), between week 4 and week 7. At week 7, renal function in both CKD groups was similar (serum creatinine: 83.98 ± 18.56 versus 83.10 ± 23.87 µmol/L, p = 0.888); however, the CH-FeCl-treated rats had a reduction in phosphate overload measured by fractional phosphate excretion (FEPi) (0.71 ± 0.2 versus 0.4 ± 0.16, p = 0.006) compared to the untreated CKD group. Our study demonstrated that CH-FeCl had an efficient chelating action on phosphate.
Assuntos
Quelantes/uso terapêutico , Quitosana/uso terapêutico , Compostos Férricos/uso terapêutico , Insuficiência Renal Crônica/tratamento farmacológico , Uremia/tratamento farmacológico , Adenina/toxicidade , Animais , Quelantes/química , Quitosana/química , Creatinina/sangue , Modelos Animais de Doenças , Compostos Férricos/química , Humanos , Hiperfosfatemia/sangue , Hiperfosfatemia/tratamento farmacológico , Fosfatos/sangue , Fosfatos/química , Ratos , Ratos Wistar , Insuficiência Renal Crônica/sangue , Insuficiência Renal Crônica/induzido quimicamente , Uremia/sangueRESUMO
In this paper, nano-hybrid particles of Ag@Fe2O3 based on O-carboxymethylchitosan were successfully synthesized using different reducing agents (NaBH4, sucrose) and without reducing agent. The smallest silver nanoparticles were those prepared without reducing agent (â¼5±3nm). The average size of silver particles prepared with NaBH4 is around 5-15nm, and for samples prepared with sucrose, the average particle size is 10-25nm. The magnetization curves are roughly reversible, indicating that γ-Fe2O3 nanoparticles transit to a superparamagnetic state. Nanocomposites subjected to antimicrobial tests showed great antimicrobial activity against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria, and good activity against the yeast Candida albicans and resistant strains of Staphylococcus aureus. The antibacterial behavior as a function of time was investigated in microbial growth kinetics, and the best nanocomposite was the one without reducing agent, which completely inhibited microbial growth for 48h.
Assuntos
Anti-Infecciosos/síntese química , Quitosana/análogos & derivados , Nanopartículas Metálicas/química , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Candida albicans/efeitos dos fármacos , Candida albicans/crescimento & desenvolvimento , Quitosana/síntese química , Quitosana/química , Quitosana/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Compostos Férricos/síntese química , Compostos Férricos/química , Compostos Férricos/farmacologia , Testes de Sensibilidade Microbiana , Nanocompostos/química , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimentoRESUMO
This paper studied the synthesis, characterization and use of the magnetic chitosan nanogel for carrying meleimidic compounds. The hydrogel polymer was prepared using O-carboxymethylchitosan, which was crosslinked with epichlorohydrin for subsequent incorporation of iron oxide magnetic nanoparticles. The characterization revealed that the magnetic material comprises about 10% of the hydrogel. This material is comprised of magnetite and maghemite and exhibits ferro-ferrimagnetic behavior. The average particle size is 4.2 nm. There was high incorporation efficiency of maleimides in the magnetic nanogel. The release was of sustained character and there was a greater release when an external magnetic field was applied. The mathematical model that best explained the process of drug release by the magnetic hydrogel was that of Peppas-Sahlin. The magnetic nanogel proved to be an excellent candidate for use in drug-delivery systems.
Assuntos
Antineoplásicos/química , Quitosana/análogos & derivados , Portadores de Fármacos/química , Polietilenoglicóis/química , Polietilenoimina/química , Adsorção , Animais , Antineoplásicos/metabolismo , Varredura Diferencial de Calorimetria , Bovinos , Quitosana/síntese química , Quitosana/química , Portadores de Fármacos/síntese química , Liberação Controlada de Fármacos , Epicloroidrina/química , Magnetismo , Nanopartículas de Magnetita/química , Nanogéis , Tamanho da Partícula , Soroalbumina Bovina/química , Espectroscopia de Mossbauer , TermogravimetriaRESUMO
PURPOSE: The discharge of colored effluents from industries is an important environmental issue and it is indispensable to remove the dyes before the water gets back to the rivers. The magnetic adsorbents present the advantage of being easily separated from the aqueous system after adsorption by positioning an external magnetic field. METHODS: Magnetic N-lauryl chitosan (L-Cht/γ-Fe(2)O(3)) particles were prepared and characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, and vibrating sample magnetometry. Remazol Red 198 (RR198) was used as a reactive dye model for adsorption on L-Cht/γ-Fe(2)O(3). The adsorption isotherms were performed at 25°C, 35°C, 45°C, and 55°C and the process was optimized using a 2(3) factorial design (analyzed factors: pH, ionic strength, and temperature). The desorption and regeneration studies were performed in a three times cycle. RESULTS: The characterization of the material indicated that the magnetic particles were introduced into the polymeric matrix. The pseudo-second order was the best model for explaining the kinetics and the Langmuir-Freundlich was the best-fitted isotherm model. At room temperature, the maximum adsorption capacity was 267 mg g(-1). The material can be reused, but with a decrease in the amount of adsorbed dye. CONCLUSIONS: L-Cht/γ-Fe(2)O(3) is a promising material to remove RR198 and probably other similar reactive dyes from aqueous effluents.
Assuntos
Compostos Azo/química , Corantes/química , Naftalenossulfonatos/química , Poluentes Químicos da Água/química , Adsorção , Quitosana/química , Cinética , Fenômenos Magnéticos , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Indústria Têxtil , TermogravimetriaRESUMO
Magnetic N-benzyl-O-carboxymethylchitosan nanoparticles were synthesized through incorporation and in situ methods and characterized by Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, and magnetization measurements. Indomethacin was incorporated into the nanoparticles via the solvent evaporation method. The indomethacin-loaded magnetic nanoparticles were characterized by the same techniques, and also by transmission electron microscopy. The nanoparticles containing the polymer showed a drug loading efficiency of between 60.8% and 74.8%, and the magnetic properties were not significantly affected by incorporation of the drug. The in vitro drug release study was carried out in simulated body fluid, pH 7.4 at 37°C. The profiles showed an initial fast release, which became slower as time progressed. The percentage of drug released after 5 h was between 60% and 90%, and the best fitting mathematical model for drug release was the Korsmeyer-Peppas model, indicating a Fickian diffusion mechanism.
Assuntos
Quitosana/análogos & derivados , Indometacina/farmacologia , Magnetismo/métodos , Nanopartículas/química , Varredura Diferencial de Calorimetria , Quitosana/síntese química , Quitosana/química , Concentração de Íons de Hidrogênio/efeitos dos fármacos , Cinética , Modelos Químicos , Nanopartículas/ultraestrutura , Tamanho da Partícula , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
It was reported the adsorption of As(III) on the surface of the chitosan-Fe-crosslinked complex. Theoretical correlation of the experimental equilibrium adsorption data for As(III)/Ch-Fe system is best explained by the non-linearized form Langmuir-Freundlich isotherm model. At optimum conditions, pH 9.0, the maximum adsorption capacity, calculated using the Langmuir-Freundlich isotherm model was 13.4 mg g⻹. The adsorption kinetics of As(III) onto Ch-Fe are described by the pseudo-first-order kinetic equation. The results of the Mössbauer spectroscopy showed that there is no redox process on the surface of the adsorbent.
Assuntos
Arsênio/química , Quitosana/química , Reagentes de Ligações Cruzadas/química , Ferro/química , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Modelos Químicos , Poluentes Químicos da Água/químicaRESUMO
O-carboxymethylchitosan films containing tetracycline were prepared by the casting method. The films were hardened by reaction with glutaraldehyde-induced crosslinking and heat treatment at 90°C, 120°C and 150°C. The effect, on the films, of hardening methods, water uptake, moisture, drug release and antimicrobial activity against Staphylococcus aureus was evaluated. The O-carboxymethylchitosan films were soluble in simulated saliva and after treatment, and the water uptake of the films decreased as the temperature or presence of glutaraldehyde increased. The antimicrobial activity of tetracycline was preserved, and efficiency was dependent on the hardening treatment to which the films were submitted.