Browsing by Author "Squella Serrano, Juan"
Now showing items 121-140 of 177
-
Núñez Vergara, Luis; Navarrete-Encina, P. A.; Ortiz, M. E.; Bollo Dragnic, Soledad; Squella Serrano, Juan (Elsevier Ireland Ltd, 1996)The reactivity of the electrochemically generated nitro radical anion from nifedipine, a nitro aryl 1,4-dihydropyridine derivative, with relevant endobiotics and thiol-containing xenobiotics, was quantitatively assessed ...
-
Núñez Vergara, Luis; Guinez-Castro, Luis; Bollo Dragnic, Soledad; Squella Serrano, Juan (1996)The reactivity of the electrochemically generated nitro radical anion from nicardipine, nitrendipine and nimodipine, all nitro aryl 1,4-dihydropyridine derivative, with relevant thiols, was quantitatively assessed by cyclic ...
-
Squella Serrano, Juan; Bollo Dragnic, Soledad; Núñez Vergara, Luis (BENTHAM SCIENCE PUBL, 2005-04)The redox chemistry of different nitro compounds of biological significance is focused to understand how the reduction of the nitro group can play an active role in several aspects as: electroanalytical determinations, ...
-
Squella Serrano, Juan; Letelier, M.; Lindermeyer, L.; Núñez Vergara, Luis (Elsevier Ireland Ltd, 1996)The electrochemical properties of nifuroxazide have been investigated in aqueous and aqueous-DMF mixed solvents. In aqueous media, a single, irreversible four-electron reduction occurs to give the hydroxylamine derivative. ...
-
Merino, M.; Núñez Vergara, Luis; Squella Serrano, Juan (WILEY-V C H VERLAG GMBH, 1999-11)A flavoenzyme cytochrome c reductase NAD(P)H mixture has been used to modify a carbon paste electrode. The modified electrode was characterized by cyclic voltammetry varying the scan rate and temperature. Cathodic and ...
-
Ortíz Yáñez, María Eugenia; Núñez Vergara, Luis; Squella Serrano, Juan (KLUWER ACADEMIC/PLENUM PUBL, 2003-02)Purpose. To evaluate the reaction of a large series of pharmacologically significant 1,4-dihydropyridine (1,4-DHP) compounds with superoxide (O-2(.-)) in dimethylsulfoxide using differential pulse voltammetry and controlled ...
-
Bollo Dragnic, Soledad; Jara Ulloa, Paola Andrea; Finger Caraccioli, Sebastián; Núñez Vergara, Luis; Squella Serrano, Juan (ELSEVIER SCIENCE SA, 2005-04-01)A scanning electrochemical microscope (SECM), in the tip generation substrate collection and feedback modes, was used in a method to characterize the electrode mechanism of the O-2/O-2*(-) couple in dimethylsulphoxide ...
-
Núñez Vergara, Luis; Díaz Araya, Guillermo; Olea Azar, Claudio; Atria Salas, Ana María; Bollo Dragnic, Soledad; Squella Serrano, Juan (1998)Purpose. To determine the formation of the one-electron reduction product from nisoldipine and its reactivity with relevant thiols in mixed medium. Methods. Cyclic voltammetry (CV) and electron paramagnetic resonance (EPR) ...
-
Álvarez Lueje, Alejandro; Pujol, Silvina; Squella Serrano, Juan; Núñez Vergara, Luis (PERGAMON-ELSEVIER SCIENCE, 2003-02-05)An HPLC reversed phase method using both UV (356 nm) and electrochemical (1000 mV) detection was developed in order to determine lercanidipine in commercial tablets. Repeatability and reproducibility were adequate. For ...
-
A selective voltammetric method to follow the hydrolytic degradation of nitrendipine and nisoldipine Álvarez Lueje, Alejandro; Sturm Schaub, Juan; Núñez Vergara, Luis; Squella Serrano, Juan (WILEY-V C H VERLAG GMBH, 2001-12)The development and application of a differential pulse voltammetric procedure for the hydrolytic degradation kinetic study of two well-known 1,4-dihydropyridine type drugs, nitrendipine and nisoldipine are presented. The ...
-
Salgado Figueroa, Paola; Jara Ulloa, Paola Andrea; Álvarez Lueje, Alejandro; Squella Serrano, Juan (2013)In this work, a new method to quantify nitrofurantoin in aqueous media using a flow injection system connected to commercially available screen-printed carbon nanofibers was developed. A pretreatment of the screen-printed ...
-
Núñez Vergara, Luis; Squella Serrano, Juan; Sturm Schaub, Juan; Báez Guerrero, Hernán; Camargo Grandón, Rodrigo (PERGAMON-ELSEVIER SCIENCE, 2001-12)A gas chroma tographic-mass spectrometric (GC-MS) method for the qualitative and quantitative determination of melatonin plus pyridoxine commercial tablets is described. Melatonin and pyridoxine were simultaneously determined ...
-
López Alarcón, Camilo; Squella Serrano, Juan; Miranda, Dante; Núñez Vergara, Luis (WILEY-V C H VERLAG GMBH, 2004-04)Spectroelectrochemical and HPLC characterization of the electrochemical oxidation in aqueous medium of a series of six N-1 and C-4 substituted 1,4-dihydropyridines is presented. Based on the analysis of spectra obtained ...
-
Yáñez, C.; Salazar, R.; Núñez Vergara, Luis; Squella Serrano, Juan (2004)Inclusion complexation between furnidipine (2,6-dimethyl-4-(2-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-tetrahydrofurfuryl 5-methyl diester), a calcium-channel antagonist, and beta-cyclodextrin (beta-CyD) ...
-
Álvarez Lueje, Alejandro; Valenzuela, C.; Squella Serrano, Juan; Núñez Vergara, Luis (AOAC INTERNATIONAL, 2005-11)In this work, a liquid chromatography stability-indicating method was developed and applied to study the hydrolytic behavior of simvastatin in different pH values and temperatures. The selected chromatographic conditions ...
-
Yáñez Soto, Claudia; Lápez Alarcón, Camilo Ignacio; Camargo Grandón, Rodrigo; Valenzuela, V.; Squella Serrano, Juan; Núñez Vergara, Luis (PERGAMON-ELSEVIER SCIENCE, 2004-05-01)A series of eight commercial C-4 substituted 1,4-dihydropyridines and other synthesized related compounds were tested for direct potential scavenger effect towards alkylperoxyl radicals and ABTS radical cation in aqueous ...
-
Squella Serrano, Juan; Núñez Vergara, Luis; Moscoso Cabello, Raúl Andrés; Pezoa Olivares, Jacqueline; Carbajo, J. (ELECTROCHEMICAL SOC INC, 2009)The electrochemical reduction of 1-methyl-4-nitro-2-carboxyimidazole (RNO2COOH) in a nonaqueous medium produced two reduction signals, which were influenced by the dissociation of the compound. The first reduction signal ...
-
Sturm Schaub, Juan; Núñez Vergara, Luis; Fuente, J. de la; Castro, C.; Navarrete Encina, Patricio; Squella Serrano, Juan (ELECTROCHEMICAL SOC INC, 2001-10)We have synthesized three nitrocompounds in order to mimic the model structure of some relevant drugs such as nifedipine, nitrendipine, nisoldipine, nimodipine, and related ones, in order to investigate the effect of ...
-
Pérez Cruz, Karina Angélica; Moncada-Basualto, Mauricio; Morales Valenzuela, Javier; Barriga González, Germán; Navarrete Encina, Patricio; Núñez Vergara, Luis; Squella Serrano, Juan; Olea Azar, Claudio (Elsevier, 2018-05)The antioxidant capacity of hydroxylated coumarins and hydroxybenzoic acids has been widely described. However, there is little information on the antioxidant activity when both systems are functionalized. In this work, ...
-
Pardo Jiménez, Viviana Gladys; Barrientos, C.; Pérez Cruz, Karina Angélica; Navarrete Encina, Patricio; Olea Azar, Claudio; Núñez Vergara, Luis; Squella Serrano, Juan (2014)In this paper, a series of six dihydropyridine-fused coumarins were synthesized and electrochemically characterized in dimethylformamide (DMF). Dihydropyridine ring oxidation on glassy carbon electrode (GCE) for condensed ...