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Kinetic and mechanistic investigations of oxidation of pentoxifylline drug by alkaline permanganate / Rajesh N. Hegde in Industrial & engineering chemistry research, Vol. 48 N° 15 (Août 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 15 (Août 2009) . - pp. 7025–7031 Titre : Kinetic and mechanistic investigations of oxidation of pentoxifylline drug by alkaline permanganate Type de document : texte imprimé Auteurs : Rajesh N. Hegde, Auteur ; Nagaraj P. Shetti, Auteur ; Sharanappa T. Nandibewoor, Auteur Année de publication : 2009 Article en page(s) : pp. 7025–7031 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hemorheologic  drug  Pentoxifylline  Alkaline  permanganate Résumé : The kinetics of oxidation of a hemorheologic drug, pentoxifylline by permanganate in alkaline medium at a constant ionic strength of 0.10 mol dm−3 was studied spectrophotometrically using a rapid kinetic HI-TECH SFA-12 accessory. The reaction between permanganate and pentoxifylline in alkaline medium exhibits 1:2 stoichiometry (pentoxifylline/permanganate). The reaction is of first order in [permanganate ion] and less than unit order dependence each in [PTX] and [OH−]. However, the orders in [PTX] and [OH−] changes from first order to zero order as their concentrations increase. A decrease in the dielectric constant of the medium increases the rate of the reaction. The effect of added products and ionic strength of the reaction medium have been investigated. The oxidation reaction in alkaline medium has been shown to proceed via a permanganate-pentoxifylline complex, which decomposes slowly in a rate-determining step followed by a fast step to give the products. A suitable mechanism is proposed. The main products were identified by TLC and spectral studies including LC−MS. The reaction constants involved in the different steps of the mechanism are calculated. The activation parameters with respect to slow step of the mechanism are computed and discussed and thermodynamic quantities are also determined. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9004145 [article] Kinetic and mechanistic investigations of oxidation of pentoxifylline drug by alkaline permanganate [texte imprimé] / Rajesh N. Hegde, Auteur ; Nagaraj P. Shetti, Auteur ; Sharanappa T. Nandibewoor, Auteur . - 2009 . - pp. 7025–7031. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 15 (Août 2009) . - pp. 7025–7031 Mots-clés : Hemorheologic  drug  Pentoxifylline  Alkaline  permanganate Résumé : The kinetics of oxidation of a hemorheologic drug, pentoxifylline by permanganate in alkaline medium at a constant ionic strength of 0.10 mol dm−3 was studied spectrophotometrically using a rapid kinetic HI-TECH SFA-12 accessory. The reaction between permanganate and pentoxifylline in alkaline medium exhibits 1:2 stoichiometry (pentoxifylline/permanganate). The reaction is of first order in [permanganate ion] and less than unit order dependence each in [PTX] and [OH−]. However, the orders in [PTX] and [OH−] changes from first order to zero order as their concentrations increase. A decrease in the dielectric constant of the medium increases the rate of the reaction. The effect of added products and ionic strength of the reaction medium have been investigated. The oxidation reaction in alkaline medium has been shown to proceed via a permanganate-pentoxifylline complex, which decomposes slowly in a rate-determining step followed by a fast step to give the products. A suitable mechanism is proposed. The main products were identified by TLC and spectral studies including LC−MS. The reaction constants involved in the different steps of the mechanism are calculated. The activation parameters with respect to slow step of the mechanism are computed and discussed and thermodynamic quantities are also determined. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9004145

Voltammetric oxidation and determination of atenolol using a carbon paste electrode / Roopa H. Patil in Industrial & engineering chemistry research, Vol. 48 N° 23 (Décembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 23 (Décembre 2009) . - pp. 10206–10210 Titre : Voltammetric oxidation and determination of atenolol using a carbon paste electrode Type de document : texte imprimé Auteurs : Roopa H. Patil, Auteur ; Rajesh N. Hegde, Auteur ; S. T. Nandibewoor, Auteur Année de publication : 2010 Article en page(s) : pp. 10206–10210 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Voltammetric--Oxidation--Determination--Atenolol--Using--Carbon--Paste--Electrode Résumé : The electrochemical oxidation of atenolol, an antihypertensive drug, was studied in a phosphate medium at a carbon paste electrode. Cyclic voltammetric results showed one well-defined oxidation peak in the potential range from 0.2 to 1.2 V under different pH conditions, but the best results were obtained at pH 10.4. The oxidation was irreversible and exhibited diffusion-controlled behavior. The response was evaluated with respect to pH and scan rate. The number of electrons transferred in the oxidation process was calculated, and the probable oxidation mechanism was proposed. The proposed differential pulse voltammetric method was successfully applied to atenolol determination in pharmaceutical samples. The analytical performance of this method has been evaluated for detection of analyte in urine as a real sample. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901163k [article] Voltammetric oxidation and determination of atenolol using a carbon paste electrode [texte imprimé] / Roopa H. Patil, Auteur ; Rajesh N. Hegde, Auteur ; S. T. Nandibewoor, Auteur . - 2010 . - pp. 10206–10210. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 23 (Décembre 2009) . - pp. 10206–10210 Mots-clés : Voltammetric--Oxidation--Determination--Atenolol--Using--Carbon--Paste--Electrode Résumé : The electrochemical oxidation of atenolol, an antihypertensive drug, was studied in a phosphate medium at a carbon paste electrode. Cyclic voltammetric results showed one well-defined oxidation peak in the potential range from 0.2 to 1.2 V under different pH conditions, but the best results were obtained at pH 10.4. The oxidation was irreversible and exhibited diffusion-controlled behavior. The response was evaluated with respect to pH and scan rate. The number of electrons transferred in the oxidation process was calculated, and the probable oxidation mechanism was proposed. The proposed differential pulse voltammetric method was successfully applied to atenolol determination in pharmaceutical samples. The analytical performance of this method has been evaluated for detection of analyte in urine as a real sample. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901163k