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The electrochemical behavior of benznidazole has been investigated in dimethylsulfoxide by cyclic voltammetry and controlled-potential electrolysis. The reduction occurs in two one-electron steps, where the first electron transfer corresponds to the reversible formation of the radical anion followed by a slow chemical reaction. The second electron transfer is attributed to the reduction of the radical anion to a dianion by an electrodic process involving a very fast cleavage of the dianion with the formation of a lactam derivative as the principal product of reduction in aprotic medium. Nitroimidazoles are compounds with a wide range of biological effects, some of which have particular therapeutic value in human and animal treatment. These compounds have exhibited chemothera-peutic effects against protozoal and bacterial infection and tumorous regions. 1 Benznidazole, N-benzil-2-nitroimidazolyl acetamide 1 is one of the most effective drugs for the treatment of Trypanosoma cruzi infection in the chronic phase as well as in the acute phase. 2 Cha-gas's disease is common in countries of Latin America, where it is a social and economic question. 3 However, little is known about benznidazole metabolism in the human body. Most of the studies on the pharmacological action of nitroimidazole suggest that the mechanism of cytotoxicity in protozoa is related to the enzymatic reduction of the nitro group and the affinity of the anion radicals to biomolecules. 4 The nitroimidazoles have been studied by electrochemical methods with success in diverse purposes such as the analytical determination in pharmaceutical formulations 5,6 and the determination on the degree of interaction of these drugs with biomolecules, because it is known that many drugs exert part of their activity via an electron-transfer process. The intention of this work is to investigate the electrochemical behavior of benznidazole in an aprotic medium using cyclic voltam-metry and controlled-potential electrolysis in order to gain insight regarding the kinetic and the electrodic mechanism for benznidazole reduction in dimethylsulfoxide. Materials and Methods Benznidazole was kindly provided by Hoffmann-La Roche & Co. The supporting electrolyte was tetrabutylammonium tetrafluor-borate (Bu 4 NBF 4 , Aldrich. The solvent was dimethylsulfoxide DMSO, Merck. Electrochemical measurements were carried out using a poten-tiostat EG&G PAR model 273, a function generator EG&G PAR model 175, and an X-Y recorder EG&G PAR model RE0089. The cell used for cyclic voltammetric experiments was of the three-electrode type, with two compartments. The working electrode was of vitreous carbon Tokai Carbon Co, type GC30 with a disk area of 0.07 cm 2 , sealed in glass. The counter electrode was a Pt ring placed below the working electrode, and the reference was a saturated calomel electrode SCE. The test solution was continuously blanketed with nitrogen for approximately 15 min before each measurement , and the working electrode surface was renewed by polishing with 0.05 m alumina f...

This paper summarizes the risk analysis methodology and challenges related to the establishment of a risk-based maintenance management system for protective coatings. Maintenance of protective coatings offshore is demanding on resources and costly. Initial selection of a coating system and the quality of the application work, including surface preparation, are vital elements for securing an acceptable coating lifetime. Most offshore installations will require, however, maintenance of the protective coatings due to degradation and/or mechanical damages. Development and implementation of a maintenance program for coatings is therefore an essential part of the overall maintenance programfor these installations. A complete maintenance program development includes: 1) establishment of coating quality status through inspection, 2) preparation of a maintenance program/strategy, and 3) preparation of detailed maintenance plans and job packages/descriptions. Optimization of maintenance and inspection programs through risk analysis is used frequently by the industry today. This principle can also be used for coating maintenance. Since the risk picture can be described by scenario, frequencies, and consequences, risk could be expressed as a function of coating status and a consequence of a coating damage. Based on this assumption, a systematic approach for optimization of the maintenance program has been developed.

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