This project aims to investigate whether it is possible to detect consentrations down to 0,3 µg/L of oseltamirir in waste water by Quartz Crystal Microbalance. The risks linked to this contaminant could be not only environmental, scientists have found that infuence recistence can propagate due to contaminats of this kind. Cases similar to the bird- and swine-flu could occure if the drug spreads through animals and mutate.   Four systems of different character was synthesised. As a result it was found that MAA functional monomer systems probably was interfering with charges within it’s own nanowires. Reference systems could not detect 0,01 mg/mL and HEMA polymer surfaces was the only reliable system, pH of 5,1. Lowest limit of detection (LOD) was found in Molecular Imprinted Polymer nanowires (MIP Nw) at 0,01 mg/mL and could be scaled down to 0,1 mg/L with increased loop size (injection at 10x that of 0,01 mg/mL at about 500 µL and a halved flow rate.)   An alternative could be nano structuring such as ”polystyrene balls” that possibly could be able to achieve surfaces with even more binding sites needed to detect the lowest limit at 0,3 µg/L.

El presente trabajo de investigación tiene como objetivo determinar cómo impactan los gastos de muestras de medicamentos éticos en la determinación del Impuesto a la Renta en empresas del sector de laboratorio farmacéutico del distrito de Ate del 2018, considerando los criterios adoptados y postura de la Administración Tributaria y tomando en cuenta la Ley del Impuesto a la Renta y la jurisprudencia actual respecto a gastos de muestras médicas. A fin de proponer alternativas que permitan a las empresas poder sustentar y deducir dichos gastos. El trabajo de investigación consta de cinco capítulos, inicia con el capítulo I marco teórico, donde se encuentra información relevante de diversas fuentes sobre el tema de investigación; en el capítulo II se presenta el plan de investigación se especifica el problema, la hipótesis e objetivos generales y específicos; en el capítulo III la metodología de investigación, se define el tipo y diseño de investigación, asimismo se determinó el tamaño de la muestra y las herramientas e instrumentos para el análisis cualitativo mediante entrevista a profundidad y el análisis cuantitativo mediante encuestas; en el capítulo IV el desarrollo de la investigación se realizó la aplicación de los dos instrumentos planteados en la investigación; más adelante, se desarrolló un caso práctico para analizar cómo impactan los gastos de muestras médicas éticas en la determinación del Impuesto a la Renta. Finalmente, en el capítulo V denominado análisis de los resultados, se brindaron conclusiones y recomendaciones respecto al trabajo de investigación. / The purpose of this research work is to determine how the expenses of medical samples impact the determination of Income Tax in companies of the Ate district Pharmaceutical Laboratory sector of 2018, considering the adopted criteria and position of the Tax Administration, taking into account the Income Tax Law and current jurisprudence regarding expenses of ethical medical samples. In order to propose alternatives that allow companies to support and deduct these expenses. The research work consists of five chapters, begins with chapter I theoretical framework, where relevant information from various sources on the subject of research is found; Then in Chapter II presents research plan the problem specifying, the hypotheses and general and specific objectives; Subsequently, in Chapter III Research Methodology, the type and design of research is defined, the size of the sample and the tools and instruments for the qualitative analysis through in-depth interview and the quantitatively analysis trough the surveys were also determined, in Chapter IV research development, the application of the two instruments proposed in the investigation was carried out; later, a case study was developed to analyze how the expenses of ethical medical samples impact the determination of Income Tax. Finally, in Chapter V Analysis of the results, conclusions and recommendations were given regarding the research work. / Tesis

Sensores eletroquímicos, constituídos de substratos metálicos modificados por metaloporfirinas e de superfícies livres de agentes modificadores, foram desenvolvidos com vistas a aplicações analíticas. Eletrodos de cobre apresentaram ação eletrocatalítica para a oxidação de ácido acetilsalícílico, com possível participação de Cu(III) como mediador na reação de transferência de elétrons. A oxidação de salbutamol sobre eletrodos de carbono vítreo foi conduzida em solução fortemente alcalina, condição na qual a determinação do analito foi viabilizada devido à eliminação de problemas associados à presença de interferentes e ao envenenamento do eletrodo. Superfícies de carbono vítreo, modificadas por adsorção e por eletropolimerização de porfirinas tetrarrutenadas de cobalto (CoTRP) e de níquel (NiTRP), respectivamente, demonstraram a versatilidade que tais compostos oferecem quanto ao modo de recobrimento do sensor, levando à obtenção de efeitos atrativos, tais como eletrocatálise e prevenção de envenenamento. Filmes de CoTRP, cujos sítios ativos são atribuídos ao par redox Ru(III)/Ru(II), mostraram-se úteis na determinação de acetaminofen, facilitando a reação de transferência de elétrons e protegendo o eletrodo contra o envenenamento. A atividade eletrocatalítica de eletrodos modificados por NiTRP, baseados em filmes com centros redox Ni(III)/Ni(II), foi evidente para a oxidação de glicose e de outros compostos orgânicos em meio alcalino. Os sensores desenvolvidos foram adaptados ao sistema BIA (batch injection analysis) para a determinação amperométrica dos analitos em amostras de produtos farmacêuticos. O método BIA mostrou-se adequado para as análises, sendo possível obter sinais transientes de corrente, boa estabilidade e alta dispersão. Os resultados bastante satisfatórios demonstram a aplicabilidade dessa técnica em análises em que alta velocidade e boa precisão são freqüentemente requisitadas. / Electrochemical sensors based on bare and modified electrodes were developed for analytical purposes. Copper electrodes exhibited electrocatalytical action for the acetylsalicylic acid oxidation, with the participation of Cu(III) species as electron-transfer mediators. The salbutamol oxidation at glassy carbon electrodes was carried out in strongly alkaline solution. In such a condition, interferences and electrode fouling were eliminated and the analyte quantification was enabled. Glassy carbon surfaces modified via adsorption and electropolymerization of tetraruthenated cobalt (CoTRP) and nickel (NiTRP) porphyrins, respectively, displayed the usefulness of these compounds for the obtainment of electrocatalysis and fouling prevention. Films based on CoTRP, from what Ru(III) are the active sites, were applicable to acetaminophen analysis by facilitating the electron transfer process and protecting the electrode against fouling. The electrocatalytical activity of modified NiTRP electrodes, based on films with Ni(III)/Ni(II) redox centers, was evident for glucose oxidation and other organic compounds. The sensors were coupled to the BIA (batch injection analysis) system for the amperometric determination of the analytes in pharmaceutical products. BIA was suitable because it presented sharp current response peaks, excellent stability and rapid washing out. The satisfactory results demonstrate the feasibility of such technique for fast analyses with good precision.

<p>For many years pharmaceutical patents and their impact on prices have been at the centre of the international debate over insufficient access to lifesaving HIV/AIDS medicines in developing countries. The conflict has largely revolved around the implementation of an intellectual property system in the developing world, subsequent the adaptation of the TRIPS Agreement, which has made a 20 year pharmaceutical patent protection mandatory for these countries and consequently contributed to high drug prices for patented medicines as well as limited the use of generic drugs.</p><p>Developing countries, where patents are already in place, have sought to reduce high drug prices by making use of compulsory licensing, a safeguarding practice allowing the production or importation of a generic medicine without the consent of the patent holder. Compulsory licences are allowed under the TRIPS Agreement, but disagreements about the conditions, under which compulsory licences are available for ‘essential medicines’, have restricted their use. A definition of the extent to which compulsory licensees can export generic drugs to developing countries unable to manufacture their own has been missing, but on 30 August 2003 the WTO announced that it had resolved this problem by lifting the TRIPS Agreement’s restrictions on exports and permitting exports of drugs produced under a compulsory license as an exception to a patent right. The main question is whether the compulsory licensing system as prescribed in the recent Decision is an ample means of improving access to patented AIDS medicines in the developing world.</p><p>By means of legal and economic reasoning this master thesis argues that the 30 August Decision on lifting TRIPS’ restrictions on exports of patented pharmaceuticals produced under compulsory licences provides complex and uncertain rules, rendering an unreliable employment of compulsory licensing. It is desirable that further recommendations are given on which generic producing companies should be awarded compulsory licences and also on which premises. In reality, the debate about compulsory licensing is part of a much wider structural problem in development policy. The solution to the inaccessibility problem requires a mix of courses of action with a functioning compulsory licensing system included. However, disagreements such as how necessary funding should be divided equitably between developed countries could protract the reaching of a pragmatic solution.</p>

For many years pharmaceutical patents and their impact on prices have been at the centre of the international debate over insufficient access to lifesaving HIV/AIDS medicines in developing countries. The conflict has largely revolved around the implementation of an intellectual property system in the developing world, subsequent the adaptation of the TRIPS Agreement, which has made a 20 year pharmaceutical patent protection mandatory for these countries and consequently contributed to high drug prices for patented medicines as well as limited the use of generic drugs. Developing countries, where patents are already in place, have sought to reduce high drug prices by making use of compulsory licensing, a safeguarding practice allowing the production or importation of a generic medicine without the consent of the patent holder. Compulsory licences are allowed under the TRIPS Agreement, but disagreements about the conditions, under which compulsory licences are available for ‘essential medicines’, have restricted their use. A definition of the extent to which compulsory licensees can export generic drugs to developing countries unable to manufacture their own has been missing, but on 30 August 2003 the WTO announced that it had resolved this problem by lifting the TRIPS Agreement’s restrictions on exports and permitting exports of drugs produced under a compulsory license as an exception to a patent right. The main question is whether the compulsory licensing system as prescribed in the recent Decision is an ample means of improving access to patented AIDS medicines in the developing world. By means of legal and economic reasoning this master thesis argues that the 30 August Decision on lifting TRIPS’ restrictions on exports of patented pharmaceuticals produced under compulsory licences provides complex and uncertain rules, rendering an unreliable employment of compulsory licensing. It is desirable that further recommendations are given on which generic producing companies should be awarded compulsory licences and also on which premises. In reality, the debate about compulsory licensing is part of a much wider structural problem in development policy. The solution to the inaccessibility problem requires a mix of courses of action with a functioning compulsory licensing system included. However, disagreements such as how necessary funding should be divided equitably between developed countries could protract the reaching of a pragmatic solution.

Health is a fundamental human right. Access to health care, which includes providing a population with safe, effective, good quality drugs at the least possible cost, is a prerequisite to realising that right. Drugs or medicines play a fundamental role in the effectiveness, efficiency and responsiveness of health care systems. Drugs also constitute a major recurrent expense in both state-run and private sector health care. To ensure that health care workers prescribe the most cost-effective drugs through the essential drugs list, training, as well as evaluation and monitoring systems must be regarded as important elements of containing costs. Pharmaceutical benefit management programmes such as pharmacoeconomics, drug utilisation review (DUR), evidence-based medicine and disease management have emerged as tools to ensure cost-effective selection and use of drugs, particularly for chronic diseases. These managed care tools are often investigated to determine whether new technologies or interventions are appropriate and have "value". Affordable prices of medicines, on their own, however, do not ensure access to medicines. Also important are reliable procurement, distribution and storage systems, and appropriately trained personnel to manage these components of drug management. Poorly regulated drug supply systems can have serious consequences such as antibiotic resistance, problems with safety or quality and most importantly wastage, as it is believed that a significant proportion of drugs purchased by the state in South Africa find their way into the private sector market through a "grey market". The general objective of this study was to review and analyse the cost and medicine usage of the "top twenty" pharmaceutical products according to the monthly pharmaceutical purchasing reports of the Department of Health in the North West Province. The research can be classified as retrospective and quantitative. The data used for the analysis were obtained over a two-year study period (1 Apr 2000 - 28 Feb 2002) from the private provider operating the medical stores in the North West Province. The results of the empirical investigation, showed the total number of "top twenty" products appearing during the study period amounted to 460 different products having a total purchasing cost of R 66,263,674.51 representing 37.2% (n = R 178,163,061.50) of all pharmaceutical products purchased during the two-year period. Through analysis it was found, when classified according the Anatomical Therapeutic Chemical (ATC) therapeutic main group, antihypertensives had the highest quantity purchased for year one (20.69%; n = 134,515,640) with cough and cold preparations revealing the highest purchasing quantity for year two (40.55%; n = 103,567,031) of all "top twenty" pharmaceuticals during the study period. Antibacterials for systemic use presented with the highest cost percentages for both years, representing 20.68% (n = R35, 568,221.31) and 16.72% (n = R 31,370,435.51) respectively. Hydrochlorothiazide presented with the highest purchasing quantity for both years when classified according to chemical substance with, Methyldopa having the highest purchasing cost for year one followed by vaccine Hib-DTP 10 dose vial (Haemophilus influenzae type B vaccine-diphtheria, pertusis and tetanus vaccine) for year two. Furthermore it was also found that the majority of the "top twenty" products were in the oral dosage form. Finally it was concluded that drugs used in the treatment of hypertension and cardiac failure were the most utilised in comparison to other "top twenty" products during the study period. Possible misappropriation based on the defined daily dose of the "top twenty" products might have occurred. In completion of this study, recommendations for future research were made. / Thesis (M.Pharm.)--North-West University, Potchefstroom Campus, 2004.

Health is a fundamental human right. Access to health care, which includes providing a population with safe, effective, good quality drugs at the least possible cost, is a prerequisite to realising that right. Drugs or medicines play a fundamental role in the effectiveness, efficiency and responsiveness of health care systems. Drugs also constitute a major recurrent expense in both state-run and private sector health care. To ensure that health care workers prescribe the most cost-effective drugs through the essential drugs list, training, as well as evaluation and monitoring systems must be regarded as important elements of containing costs. Pharmaceutical benefit management programmes such as pharmacoeconomics, drug utilisation review (DUR), evidence-based medicine and disease management have emerged as tools to ensure cost-effective selection and use of drugs, particularly for chronic diseases. These managed care tools are often investigated to determine whether new technologies or interventions are appropriate and have "value". Affordable prices of medicines, on their own, however, do not ensure access to medicines. Also important are reliable procurement, distribution and storage systems, and appropriately trained personnel to manage these components of drug management. Poorly regulated drug supply systems can have serious consequences such as antibiotic resistance, problems with safety or quality and most importantly wastage, as it is believed that a significant proportion of drugs purchased by the state in South Africa find their way into the private sector market through a "grey market". The general objective of this study was to review and analyse the cost and medicine usage of the "top twenty" pharmaceutical products according to the monthly pharmaceutical purchasing reports of the Department of Health in the North West Province. The research can be classified as retrospective and quantitative. The data used for the analysis were obtained over a two-year study period (1 Apr 2000 - 28 Feb 2002) from the private provider operating the medical stores in the North West Province. The results of the empirical investigation, showed the total number of "top twenty" products appearing during the study period amounted to 460 different products having a total purchasing cost of R 66,263,674.51 representing 37.2% (n = R 178,163,061.50) of all pharmaceutical products purchased during the two-year period. Through analysis it was found, when classified according the Anatomical Therapeutic Chemical (ATC) therapeutic main group, antihypertensives had the highest quantity purchased for year one (20.69%; n = 134,515,640) with cough and cold preparations revealing the highest purchasing quantity for year two (40.55%; n = 103,567,031) of all "top twenty" pharmaceuticals during the study period. Antibacterials for systemic use presented with the highest cost percentages for both years, representing 20.68% (n = R35, 568,221.31) and 16.72% (n = R 31,370,435.51) respectively. Hydrochlorothiazide presented with the highest purchasing quantity for both years when classified according to chemical substance with, Methyldopa having the highest purchasing cost for year one followed by vaccine Hib-DTP 10 dose vial (Haemophilus influenzae type B vaccine-diphtheria, pertusis and tetanus vaccine) for year two. Furthermore it was also found that the majority of the "top twenty" products were in the oral dosage form. Finally it was concluded that drugs used in the treatment of hypertension and cardiac failure were the most utilised in comparison to other "top twenty" products during the study period. Possible misappropriation based on the defined daily dose of the "top twenty" products might have occurred. In completion of this study, recommendations for future research were made. / Thesis (M.Pharm.)--North-West University, Potchefstroom Campus, 2004.

Le procédé de granulation en voie humide nécessite l'ajout d'un agent d’enrobage ou liant, typiquement composé d'agents tensioactifs, d'eau, de plastifiant et de charge hydrophobe. Cependant, dans les procédés de granulation en voie sèche, l'agent d’enrobage est ajouté sous la forme de fines particules solides. L’objectif de ce travail est double : d’une part, examiner le comportement des particules dans les systèmes secs et aqueux aux échelles microscopique et mésoscopique, et d’autre part, développer des méthodologies prédictives permettant de choisir le liant adéquat et formuler la bonne solution d’enrobage. Dans le cadre de cette étude, nous avons utilisées l'hydroxypropyl-méthylcellulose (HPMC) et la cellulose d'éthyle (EC) comme agents d’enrobage, polyvinylpyrrolidone (PVP) et la cellulose microcristalline (MCC) généralement utilisés comme liants, l'acide stéarique (SA) qui est une charge hydrophobe, et le polyéthylène glycol (PEG) comme plastifiant. Tous ces matériaux sont largement utilisés dans les industries alimentaires et pharmaceutiques. La réussite d’une granulation dépend de l’affinité entre les particules primaires et le liant. Afin de prédire l'affinité liant-substrat en milieu sec et en milieu aqueux, nous avons comparé deux approches; la première est basée sur le travail de l'adhésion alors que la seconde s’appuie sur le concept de résistance à la traction idéale. L’équation de résistance à la traction idéale a été étendue aux systèmes ternaires dans le but de l’appliquer pour la granulation en milieu aqueux. Les approches développées ont été ensuite confrontées aux données expérimentales sur différent systèmes (composées de PVP, MCC, HPMC, SA, EC, PEG et l'eau). Nous avons ainsi trouvé que l’approche basée sur le travail d'adhésion semble donner de meilleures prédictions des affinités. Les deux approches prédisent que le HPMC est un bon liant pour le MCC. Les résultats indiquent également que le PEG a une bonne affinité avec le HPMC et le SA. Nous avons ensuite étudié la structure des agglomérats formés dans les formulations colloïdales utilisées dans les procédés d’enrobage. Pour ce faire, nous nous sommes appuyés sur des analyses expérimentales et des simulations mésoscopiques. Ces dernières reposent sur l’utilisation de la méthode de dynamique des particules dissipatives (DPD) dans laquelle les composés sont décrits comme un ensemble de billes souples (approche « coarse-grain ») interagissant selon le modèle de Flory-Huggins. Les interactions répulsives entre les billes ont été évaluées en utilisant le paramètre de solubilité (δ) calculé par simulation moléculaire tout-atome. Les résultats de simulation DPD ont été comparés aux résultats expérimentaux obtenus par plusieurs voies : cryogénique-MEB, analyse de distribution de taille de particule et par la technique DSC. Les résultats de la simulation DPD montrent que le polymère HPMC est un meilleur agent stabilisant pour le SA que le PVP et le MCC. En outre, HPMC est capable de recouvrir la particule de SA d'une couche épaisse et d’y pénétrer en profondeur, empêchant ainsi l’agglomération et la croissance des cristaux de SA. Néanmoins, HPMC est incapable de stabiliser les particules de SA lorsque celles-ci sont en quantités élevées (supérieurs à 10% (w/w)). Nous constatons également que le PEG se diffuse à l'intérieur des chaînes de HPMC entrainant l’extension de ce dernier, formant ainsi un polymère composite lisse. Les résultats expérimentaux montrent des tendances similaires; l’analyse de la distribution de taille de particule indique qu’en présence de HPMC, pour de faible pourcentages de SA (au-dessous de 10% (w/w)), la majorité des particules de SA sont inférieures à 1 μm de diamètre. Les images MEB révèlent que HPMC entoure les cristaux de SA avec un film texturé et ancre sur leur surface. / Wet granulation process requires the addition of a coating agent or binder, typically composed of surfactants, water, plasticizers and fillers. In dry granulation however, the coating agent is added to the system in the form of fine solid particles. Our goals are to investigate the particles behaviour and agglomeration mechanism in dry and aqueous systems at the micro and meso scales, and also, to develop predictive methodologies and theoretical tools of investigation allowing to choose the adequate binder and to formulate the right coating solution. In this study we chose materials widely used in food and pharmaceutical industries, including; coating agents such as Hydroxypropyl-methylcellulose (HPMC) and Ethyl cellulose (EC), binders such as Polyvinylpyrrolidone (PVP) and Microcrystalline cellulose (MCC), hydrophobic filler such as Stearic acid (SA) and plasticizer such as Polyethylene glycol (PEG). A successful granulation requires good affinity between host and guest particles. In this context, in the first part of this work, two approaches to predict the binder-substrate affinity in dry and in aqueous media were compared; one based on the work of adhesion and the other based on the ideal tensile strength. The concept of ideal tensile strength was extended to ternary systems and applied for granulation in aqueous media. The developed approaches were thereafter tested for various systems (composed of PVP, MCC, HPMC, SA, EC, PEG and water) and compared to experimental observations. Approaches yielded results in good agreement with the experimental observations, but the work of adhesion approach might give more accurate affinity predictions on the particles affinity than the ideal tensile strength approach. Both approaches predicted that HPMC is a good binder for MCC. Results also indicated that PEG has a good affinity with HPMC and SA. In a second part of our work, we used mesoscale simulations and experimental techniques to investigate the structure of agglomerates formed in aqueous colloidal formulations used in coating and granulation processes. For the simulations, dissipative particle dynamics (DPD) and a coarse-grained approach were used. In the DPD method, the compounds were described as a set of soft beads interacting according to the Flory-Huggins model. The repulsive interactions between the beads were evaluated using the solubility parameter (δ) as input, where, δ was calculated by all-atom molecular simulations. The mesoscale simulation results were compared to experimental results obtained by Cryogenic-SEM, particle size distribution analysis and DSC technique. According to the DPD simulations, HPMC polymer is a better stabilizing agent for SA than PVP and MCC. In addition, HPMC is able to cover the SA particle with a thick layer ant to adsorb in depth into its inner core, preventing SA agglomeration and crystal growth. But, for high amounts of SA (above 10% (w/w)), HPMC is unable to fully stabilize SA. We also found that PEG polymer diffuses inside HPMC chains thereby extending and softening the composite polymer. Experimental results presented similar trends; particle size distribution analysis showed that in the presence of HPMC, for low percentages of SA (below 10% (w/w)), the majority of SA particles are below 1 μm in diameter. SEM images revealed that HPMC surrounds SA crystals with a hatching textured film and anchors on their surface.

nÃo hà / Esta dissertaÃÃo analisa a arrecadaÃÃo do ICMS (Imposto sobre CirculaÃÃo de Mercadorias) no setor de medicamentos e produtos farmacÃuticos no estado do Cearà apÃs a implantaÃÃo do regime de carga lÃquida, regulado pelo Decreto nÂ. 29.816 de 06 de agosto de 2009. O objetivo principal à verificar se a estrutura de arrecadaÃÃo de ICMS neste setor se alterou apÃs esta mudanÃa. Nestes termos, para alcanÃar este objetivo, especificou-se um modelo economÃtrico de regressÃo mÃltipla onde a variÃvel dependente foi a arrecadaÃÃo total mensal de ICMS dos setores atacadista (CNAE 4644301 (ClassificaÃÃo Nacional de Atividades EconÃmicas) e varejista de produtos farmacÃuticos com manipulaÃÃo de fÃrmula (CNAE 4771702), no perÃodo de janeiro de 2006 a junho de 2014. As variÃveis exÃgenas de controle empregadas no modelo foram o faturamento das empresas, taxa de juros, taxa de desemprego, alÃm de variÃveis que captam a tendÃncia e a sazonalidade das sÃries de ICMS. Adicionalmente, incorporou-se uma variÃvel dummy para verificar o efeito sobre a arrecadaÃÃo de ICMS apÃs a mudanÃa do regime de cobranÃa. Entre os resultados obtidos, no setor atacadista, os dados mostraram que houve uma reduÃÃo no recolhimento de ICMS a partir da implantaÃÃo do novo sistema tributÃrio. Entretanto, a alteraÃÃo da legislaÃÃo influenciou de forma positiva o ICMS no setor varejista de produtos farmacÃuticos com manipulaÃÃo de fÃrmula. / This work describes the analysis of the ICMS revenue in the drug and pharmaceutical sector in the Cearà state after the implementation of net charge regime, governed by Decree no. 29 816 of August 6, 2009. The effect of net charge on the collection of the tax from the companies was measured by a multiple regression model where the dependent variable was the total monthly ICMS collection from the wholesaler (CNAE 4644301) and retailer pharmaceuticals with formula manipulation (CNAE 4771702) sectors, during the period of January 2006 to June 2014. The exogenous variables used in the model were the companies billing, interest rate, unemployment rate and a variable "dummy" equal to one from October 2009. The study involving the wholesale sector showed that there was a reduction in the payment of the ICMS after the implementation of the new tax system. However, the new legislation positively influenced the ICMS in the retail sector of pharmaceutical products with formula manipulation.

Sensores eletroquímicos, constituídos de substratos metálicos modificados por metaloporfirinas e de superfícies livres de agentes modificadores, foram desenvolvidos com vistas a aplicações analíticas. Eletrodos de cobre apresentaram ação eletrocatalítica para a oxidação de ácido acetilsalícílico, com possível participação de Cu(III) como mediador na reação de transferência de elétrons. A oxidação de salbutamol sobre eletrodos de carbono vítreo foi conduzida em solução fortemente alcalina, condição na qual a determinação do analito foi viabilizada devido à eliminação de problemas associados à presença de interferentes e ao envenenamento do eletrodo. Superfícies de carbono vítreo, modificadas por adsorção e por eletropolimerização de porfirinas tetrarrutenadas de cobalto (CoTRP) e de níquel (NiTRP), respectivamente, demonstraram a versatilidade que tais compostos oferecem quanto ao modo de recobrimento do sensor, levando à obtenção de efeitos atrativos, tais como eletrocatálise e prevenção de envenenamento. Filmes de CoTRP, cujos sítios ativos são atribuídos ao par redox Ru(III)/Ru(II), mostraram-se úteis na determinação de acetaminofen, facilitando a reação de transferência de elétrons e protegendo o eletrodo contra o envenenamento. A atividade eletrocatalítica de eletrodos modificados por NiTRP, baseados em filmes com centros redox Ni(III)/Ni(II), foi evidente para a oxidação de glicose e de outros compostos orgânicos em meio alcalino. Os sensores desenvolvidos foram adaptados ao sistema BIA (batch injection analysis) para a determinação amperométrica dos analitos em amostras de produtos farmacêuticos. O método BIA mostrou-se adequado para as análises, sendo possível obter sinais transientes de corrente, boa estabilidade e alta dispersão. Os resultados bastante satisfatórios demonstram a aplicabilidade dessa técnica em análises em que alta velocidade e boa precisão são freqüentemente requisitadas. / Electrochemical sensors based on bare and modified electrodes were developed for analytical purposes. Copper electrodes exhibited electrocatalytical action for the acetylsalicylic acid oxidation, with the participation of Cu(III) species as electron-transfer mediators. The salbutamol oxidation at glassy carbon electrodes was carried out in strongly alkaline solution. In such a condition, interferences and electrode fouling were eliminated and the analyte quantification was enabled. Glassy carbon surfaces modified via adsorption and electropolymerization of tetraruthenated cobalt (CoTRP) and nickel (NiTRP) porphyrins, respectively, displayed the usefulness of these compounds for the obtainment of electrocatalysis and fouling prevention. Films based on CoTRP, from what Ru(III) are the active sites, were applicable to acetaminophen analysis by facilitating the electron transfer process and protecting the electrode against fouling. The electrocatalytical activity of modified NiTRP electrodes, based on films with Ni(III)/Ni(II) redox centers, was evident for glucose oxidation and other organic compounds. The sensors were coupled to the BIA (batch injection analysis) system for the amperometric determination of the analytes in pharmaceutical products. BIA was suitable because it presented sharp current response peaks, excellent stability and rapid washing out. The satisfactory results demonstrate the feasibility of such technique for fast analyses with good precision.