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Ramón Martínez-máñez - One of the best experts on this subject based on the ideXlab platform.
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Functional Magnetic Mesoporous Silica Microparticles Capped with an Azo-Derivative: A Promising Colon Drug Delivery Device.
Molecules, 2018Co-Authors: Adrián H. Teruel, Carmen Coll, Ana M. Costero, Daniel Ferri, Margarita Parra, Pablo Gaviña, M. D. Marcos, Marta González-Álvarez, Virginia Merino, Ramón Martínez-máñezAbstract:Magnetic micro-sized mesoporous silica particles were used for the preparation of a gated material able to release an entrapped cargo in the presence of an azo-reducing agent and, to some extent, at acidic pH. The magnetic mesoporous microparticles were loaded with Safranin O and the external surface was functionalized with an azo derivative 1 (bearing a carbamate linkage) yielding solid S1. Aqueous suspensions of S1 at pH 7.4 showed negligible Safranin O release due to the presence of the bulky azo derivative attached onto the external surface of the inorganic scaffold. However, in the presence of sodium dithionite (azoreductive agent), a remarkable Safranin O delivery was observed. At acidic pH, a certain Safranin O release from S1 was also found. The pH-triggered Safranin O delivery was ascribed to the acid-induced hydrolysis of the carbamate moiety that linked the bulky azo derivatives onto the mesoporous inorganic magnetic support. The controlled release behavior of S1 was also tested using a model that simulated the gastro intestinal tract.
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Supplementary Material from Mesoporous silica microparticles gated with a bulky azo derivative for the controlled release of dyes/drugs in colon
2018Co-Authors: Daniel Ferri, Adrián H. Teruel, Ana M. Costero, Margarita Parra, Pablo Gaviña, Virginia Merino, Jamal El Haskouri, Pedro Amorós, Félix Sancenón, Ramón Martínez-máñezAbstract:Mesoporous silica microparticles were prepared, loaded with the dye Safranin O (M-Saf) or with the drug budesonide (M-Bud) and capped by the grafting of a bulky azo derivative. Cargo release from M-Saf at different pH values (mimicking those found in the gastrointestinal tract (GIT)) in the absence or presence of sodium dithionite (a reducing agent mimicking azoreductase enzyme present in the colon) was tested. Negligible Safranin O release was observed at pH 6.8 and 4.5, whereas a moderate delivery at pH 1.2 was noted and attributed to the hydrolysis of the urea bond that linked the azo derivative onto the external surface of the inorganic scaffold. Moreover, a marked release was observed when sodium dithionite was present and was ascribed to the rupture of the azo bond in the molecular gate. Budesonide release from M-Bud in the presence of sodium dithionite was also assessed by UV–vis and HPLC measurements. In addition, preliminary in vivo experiments with M-Saf carried out in mice indicated that the chemical integrity of the microparticles remained unaltered in the stomach and the small intestine, and Safranin O seemed to be released in the colon
R. K. Patel - One of the best experts on this subject based on the ideXlab platform.
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correction removal of Safranin o dye from aqueous solution using modified red mud kinetics and equilibrium studies
RSC Advances, 2015Co-Authors: Manoj Kumar Sahu, R. K. PatelAbstract:Correction for ‘Removal of Safranin-O dye from aqueous solution using modified red mud: kinetics and equilibrium studies’ by Manoj Kumar Sahu et al., RSC Adv., 2015, 5, 78491–78501.
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adsorption of Safranin o dye on co2 neutralized activated red mud waste process modelling analysis and optimization using statistical design
RSC Advances, 2015Co-Authors: Manoj Kumar Sahu, Uttam Kumar Sahu, R. K. PatelAbstract:Response surface methodology (RSM) was applied to examine the removal of hazardous Safranin-O dye from aqueous solution by CO2 neutralized activated red mud. A 24 full factorial central composite design (CCD) was used to evaluate the effects of adsorption parameters such as, adsorbent dose (X1), temperature (X2), solution pH (X3) and initial Safranin-O concentration (X4) on percentage removal of Safranin-O dye from aqueous solution. Analysis of variance (ANOVA) exhibit a high R2 value of 0.9655, indicating second-order regression model excellently evaluate the experimental data. The interaction effects of the main factor and optimum condition of the process were determined from contour and response surface plots, respectively. In addition, the isotherm study revealed that, the adsorption data were best fitted to Langmuir model with high correlation value of 0.994 and adsorption capacity of 9.7680 mg g−1. The optimum operating condition for adsorption of Safranin-O dye were obtained as adsorbent dose (0.62 g), temperature (29.06 °C), pH (8.3) and initial Safranin-O concentration (37.3 mg L−1). At the optimum condition, the adsorption of Safranin-O from aqueous solution was found to be 94.5 ± 0.1%.
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correction adsorption of Safranin o dye on co2 neutralized activated red mud waste process modelling analysis and optimization using statistical design
RSC Advances, 2015Co-Authors: Manoj Kumar Sahu, Uttam Kumar Sahu, R. K. PatelAbstract:Response surface methodology (RSM) was applied to examine the removal of hazardous Safranin-O dye from aqueous solution by CO2 neutralized activated red mud. A 24 full factorial central composite design (CCD) was used to evaluate the effects of adsorption parameters such as, adsorbent dose (X1), temperature (X2), solution pH (X3) and initial Safranin-O concentration (X4) on percentage removal of Safranin-O dye from aqueous solution. Analysis of variance (ANOVA) exhibit a high R2 value of 0.9655, indicating second-order regression model excellently evaluate the experimental data. The interaction effects of the main factor and optimum condition of the process were determined from contour and response surface plots, respectively. In addition, the isotherm study revealed that, the adsorption data were best fitted to Langmuir model with high correlation value of 0.994 and adsorption capacity of 9.7680 mg g−1. The optimum operating condition for adsorption of Safranin-O dye were obtained as adsorbent dose (0.62 g), temperature (29.06 °C), pH (8.3) and initial Safranin-O concentration (37.3 mg L−1). At the optimum condition, the adsorption of Safranin-O from aqueous solution was found to be 94.5 ± 0.1%.
Adrián H. Teruel - One of the best experts on this subject based on the ideXlab platform.
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Functional Magnetic Mesoporous Silica Microparticles Capped with an Azo-Derivative: A Promising Colon Drug Delivery Device.
Molecules, 2018Co-Authors: Adrián H. Teruel, Carmen Coll, Ana M. Costero, Daniel Ferri, Margarita Parra, Pablo Gaviña, M. D. Marcos, Marta González-Álvarez, Virginia Merino, Ramón Martínez-máñezAbstract:Magnetic micro-sized mesoporous silica particles were used for the preparation of a gated material able to release an entrapped cargo in the presence of an azo-reducing agent and, to some extent, at acidic pH. The magnetic mesoporous microparticles were loaded with Safranin O and the external surface was functionalized with an azo derivative 1 (bearing a carbamate linkage) yielding solid S1. Aqueous suspensions of S1 at pH 7.4 showed negligible Safranin O release due to the presence of the bulky azo derivative attached onto the external surface of the inorganic scaffold. However, in the presence of sodium dithionite (azoreductive agent), a remarkable Safranin O delivery was observed. At acidic pH, a certain Safranin O release from S1 was also found. The pH-triggered Safranin O delivery was ascribed to the acid-induced hydrolysis of the carbamate moiety that linked the bulky azo derivatives onto the mesoporous inorganic magnetic support. The controlled release behavior of S1 was also tested using a model that simulated the gastro intestinal tract.
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Supplementary Material from Mesoporous silica microparticles gated with a bulky azo derivative for the controlled release of dyes/drugs in colon
2018Co-Authors: Daniel Ferri, Adrián H. Teruel, Ana M. Costero, Margarita Parra, Pablo Gaviña, Virginia Merino, Jamal El Haskouri, Pedro Amorós, Félix Sancenón, Ramón Martínez-máñezAbstract:Mesoporous silica microparticles were prepared, loaded with the dye Safranin O (M-Saf) or with the drug budesonide (M-Bud) and capped by the grafting of a bulky azo derivative. Cargo release from M-Saf at different pH values (mimicking those found in the gastrointestinal tract (GIT)) in the absence or presence of sodium dithionite (a reducing agent mimicking azoreductase enzyme present in the colon) was tested. Negligible Safranin O release was observed at pH 6.8 and 4.5, whereas a moderate delivery at pH 1.2 was noted and attributed to the hydrolysis of the urea bond that linked the azo derivative onto the external surface of the inorganic scaffold. Moreover, a marked release was observed when sodium dithionite was present and was ascribed to the rupture of the azo bond in the molecular gate. Budesonide release from M-Bud in the presence of sodium dithionite was also assessed by UV–vis and HPLC measurements. In addition, preliminary in vivo experiments with M-Saf carried out in mice indicated that the chemical integrity of the microparticles remained unaltered in the stomach and the small intestine, and Safranin O seemed to be released in the colon
Gopinatha Suresh Kumar - One of the best experts on this subject based on the ideXlab platform.
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sequence selective binding of phenazinium dyes phenoSafranin and Safranin o to guanine cytosine deoxyribopolynucleotides spectroscopic and thermodynamic studies
Journal of Physical Chemistry B, 2010Co-Authors: Ishita Saha, Maidul Hossain, Gopinatha Suresh KumarAbstract:The sequence selectivity of the DNA binding of the phenazinium dyes phenoSafranin and Safranin O have been investigated with four sequence-specific deoxyribopolynucleotides from spectroscopic and calorimetric studies. The alternating guanine−cytosine sequence selectivity of the dyes has been revealed from binding affinity values, circular dichroism, thermal melting, competition dialysis, and calorimetric results. The binding affinities of both the dyes to the polynucleotides were of the order of 105 M−1, but the values were higher for the guanine−cytosine polynucleotides over adenine−thymine ones. PhenoSafranin had a higher binding affinity compared to Safranin O. Isothermal titration calorimetric studies revealed that the binding reactions were exothermic and favored by negative enthalpy and predominantly large positive entropy contributions in all cases except poly(dA)·poly(dT) where the profile was anomalous. Although charged, nonpolyelectrolytic contribution was revealed to be dominant to the free ene...
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sequence selective binding of phenazinium dyes phenoSafranin and Safranin o to guanine cytosine deoxyribopolynucleotides spectroscopic and thermodynamic studies
Journal of Physical Chemistry B, 2010Co-Authors: Ishita Saha, Maidul Hossain, Gopinatha Suresh KumarAbstract:The sequence selectivity of the DNA binding of the phenazinium dyes phenoSafranin and Safranin O have been investigated with four sequence-specific deoxyribopolynucleotides from spectroscopic and calorimetric studies. The alternating guanine-cytosine sequence selectivity of the dyes has been revealed from binding affinity values, circular dichroism, thermal melting, competition dialysis, and calorimetric results. The binding affinities of both the dyes to the polynucleotides were of the order of 10(5) M(-1), but the values were higher for the guanine-cytosine polynucleotides over adenine-thymine ones. PhenoSafranin had a higher binding affinity compared to Safranin O. Isothermal titration calorimetric studies revealed that the binding reactions were exothermic and favored by negative enthalpy and predominantly large positive entropy contributions in all cases except poly(dA)·poly(dT) where the profile was anomalous. Although charged, nonpolyelectrolytic contribution was revealed to be dominant to the free energy of binding. The negative heat capacity values obtained from the temperature dependence of enthalpy changes, which were higher for phenoSafranin compared to Safranin O, suggested significant hydrophobic contribution to the binding process. In aggregate, the data presents evidence for the alternating guanine-cytosine base pair selectivity of these phenazinium dyes and a stronger binding of phenoSafranin over Safranin O.
Manoj Kumar Sahu - One of the best experts on this subject based on the ideXlab platform.
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correction removal of Safranin o dye from aqueous solution using modified red mud kinetics and equilibrium studies
RSC Advances, 2015Co-Authors: Manoj Kumar Sahu, R. K. PatelAbstract:Correction for ‘Removal of Safranin-O dye from aqueous solution using modified red mud: kinetics and equilibrium studies’ by Manoj Kumar Sahu et al., RSC Adv., 2015, 5, 78491–78501.
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adsorption of Safranin o dye on co2 neutralized activated red mud waste process modelling analysis and optimization using statistical design
RSC Advances, 2015Co-Authors: Manoj Kumar Sahu, Uttam Kumar Sahu, R. K. PatelAbstract:Response surface methodology (RSM) was applied to examine the removal of hazardous Safranin-O dye from aqueous solution by CO2 neutralized activated red mud. A 24 full factorial central composite design (CCD) was used to evaluate the effects of adsorption parameters such as, adsorbent dose (X1), temperature (X2), solution pH (X3) and initial Safranin-O concentration (X4) on percentage removal of Safranin-O dye from aqueous solution. Analysis of variance (ANOVA) exhibit a high R2 value of 0.9655, indicating second-order regression model excellently evaluate the experimental data. The interaction effects of the main factor and optimum condition of the process were determined from contour and response surface plots, respectively. In addition, the isotherm study revealed that, the adsorption data were best fitted to Langmuir model with high correlation value of 0.994 and adsorption capacity of 9.7680 mg g−1. The optimum operating condition for adsorption of Safranin-O dye were obtained as adsorbent dose (0.62 g), temperature (29.06 °C), pH (8.3) and initial Safranin-O concentration (37.3 mg L−1). At the optimum condition, the adsorption of Safranin-O from aqueous solution was found to be 94.5 ± 0.1%.
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correction adsorption of Safranin o dye on co2 neutralized activated red mud waste process modelling analysis and optimization using statistical design
RSC Advances, 2015Co-Authors: Manoj Kumar Sahu, Uttam Kumar Sahu, R. K. PatelAbstract:Response surface methodology (RSM) was applied to examine the removal of hazardous Safranin-O dye from aqueous solution by CO2 neutralized activated red mud. A 24 full factorial central composite design (CCD) was used to evaluate the effects of adsorption parameters such as, adsorbent dose (X1), temperature (X2), solution pH (X3) and initial Safranin-O concentration (X4) on percentage removal of Safranin-O dye from aqueous solution. Analysis of variance (ANOVA) exhibit a high R2 value of 0.9655, indicating second-order regression model excellently evaluate the experimental data. The interaction effects of the main factor and optimum condition of the process were determined from contour and response surface plots, respectively. In addition, the isotherm study revealed that, the adsorption data were best fitted to Langmuir model with high correlation value of 0.994 and adsorption capacity of 9.7680 mg g−1. The optimum operating condition for adsorption of Safranin-O dye were obtained as adsorbent dose (0.62 g), temperature (29.06 °C), pH (8.3) and initial Safranin-O concentration (37.3 mg L−1). At the optimum condition, the adsorption of Safranin-O from aqueous solution was found to be 94.5 ± 0.1%.
