Determinação espectrofotométrica de hexametilenotetramina (HMT) em medicamentos, utilizando ácido cromotrópico e forno de micro-ondas

This paper proposes a methodology for spectrophotometric determination of hexamethylenetetramine (HMT) by using chromotropic acid in a phosphoric acid media employing a domestic microwave oven as a source of heating. The reddish-purple soluble product is quantitatively formed after 30 s of irradiation and obeys the Beer´s law in the range between 0.1-1.2 mg L-1 HMT (r = 0.99925). The method was applied successfully in commercial pharmaceutical preparations containing dyes in their composition. The results showed that the method proposed is feasible for simplicity, speed, low cost, precision and accuracy when compared with United States Pharmacopeia official method

Spectrophotometric determination of hexamethylenetetramine (HMT) in pharmaceutical preparations using chromotropic acid and microwave oven

This paper proposes a methodology for spectrophotometric determination of hexamethylenetetramine (HMT) by using chromotropic acid in a phosphoric acid media employing a domestic microwave oven as a source of heating. The reddish-purple soluble product is quantitatively formed after 30 s of irradiation and obeys the Beer´s law in the range between 0.1-1.2 mg L-1 HMT (r = 0.99925). The method was applied successfully in commercial pharmaceutical preparations containing dyes in their composition. The results showed that the method proposed is feasible for simplicity, speed, low cost, precision and accuracy when compared with United States Pharmacopeia official method.24582463Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Development and application of a portable instrument for drugs analysis in pharmaceutical preparations

This article describes the application and performance of an inexpensive, simple and portable device for colorimetric quantitative determination of drugs in pharmaceutical preparations. The sensor is a light detector resistor (LDR) incorporated into a black PTFE cell and coupled to a low-cost multimeter (Ohmmeter). Quantitative studies were performed with captopril/p-chloranil/H2O2 and methyldopa/ammonium molybdate systems. Calibration curves were obtained by plotting the electrical resistance of the LDR against the concentration of the colored species in the ranges 1.84 × 10-4 to 1.29 × 10-3mol L-1 and 5.04 × 10-4 to 2.52 × 10-3 mol L-1 for captopril/p-chloranil/H2O2 and methyldopa/ammonium molybdate systems, respectively, exhibiting good coefficients of determination. Statistical analysis of the results obtained showed no significant difference between the proposed methodologies and the official reported methods, as evidenced by the t-test and variance ratio at a 95% confidence level. The results of this study demonstrate the applicability of the instrument for simple, accurate, precise, fast,in situ and low-cost colorimetric analysis of drugs in pharmaceutical products.Este artigo descreve o desenvolvimento e a aplicação de um dispositivo portátil, simples e barato para a determinação colorimétrica quantitativa de fármacos em formulações farmacêuticas. O sensor é um resistor detector de luz (RDL) colocado numa célula de PTFE e acoplado a um multímetro de baixo custo. Os estudos quantitativos foram realizados utilizando captopril/p-cloranil/H2O2 e metildopa/molibdato de amônio como sistemas reacionais. As curvas de calibração foram obtidas através da representação gráfica da resistência elétrica do RDL contra a concentração dos complexos coloridos formados nas faixas de 1,84 × 10-4 e 1,29 × 10-3 mol L-1 e 5,04 × 10-4 e 2,52 × 10- 3 mol L-1 para captopril/p-cloranil/H2O2 e de metildopa/molibdato de amônio, respectivamente, com bons coeficientes de determinação. As análises estatísticas dos resultados obtidos mostraram que não houve diferença significativa entre os métodos propostos e os métodos oficiais como evidente a partir dos testes "t-Student" eF-Fisher, com nível de confiança de 95%. Os resultados deste estudo demonstram que o instrumento proposto neste trabalho é simples, de fácil operação, baixo custo e apresentou boa exatidão e boa precisão para o doseamento de fármacos em medicamentos

A simplified reflectometric method for the rapid determination of dipyrone in pharmaceutical formulations

This paper describes a simple, portable and environmentally friendly method for the rapid determination of dipyrone in pharmaceuticals by using diffuse reflectance spectroscopy. The proposed method is based on the reflectance measurements of the orange compound produced from the spot test reaction between dipyrone and p-dimethylaminocinnamaldehyde (p-DAC), in acid medium, using a filter paper as solid support. Experimental design methodologies were used to optimize the measurement conditions. All reflectance measurements were carried out at 510 nm and the linear range was from 1.42 × 10-4-2.85 × 10-3 mol L-1, with a correlation coefficient of 0.999. The limit of detection (LOD) and the limit of quantification (LOQ) were 1.20 × 10-5 mol L-1 and 4.00 × 10-5 mol L-1, respectively. The intraday precision and interday precision were studied for 10 replicate analyses of 7.90 × 10-4 mol L-1 dipyrone solution. The coefficients of variation were 1.1 and 0.9%, respectively. The proposed method was applied successfully to the determination of dipyrone in commercial brands of pharmaceuticals. No interferences were observed from the common excipients in formulations. The results obtained by the proposed method were favorably compared with those given by the Brazilian Pharmacopoeia procedure at 95% confidence level. ©2007 Sociedade Brasileira de Química

Development and application of a portable instrument for drugs analysis in pharmaceutical preparations

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)This article describes the application and performance of an inexpensive, simple and portable device for colorimetric quantitative determination of drugs in pharmaceutical preparations. The sensor is a light detector resistor (LDR) incorporated into a black PTFE cell and coupled to a low-cost multimeter (Ohmmeter). Quantitative studies were performed with captopril/p-chloranil/H2O2 and methyldopa/ammonium molybdate systems. Calibration curves were obtained by plotting the electrical resistance of the LDR against the concentration of the colored species in the ranges 1.84 x 10(-4) to 1.29 x 10(-3) mol L-1 and 5.04 x 10(-4) to 2.52 x 10(-3) mol L-1 for captopril/p-chloranil/H2O2 and methyldopa/ammonium molybdate systems, respectively, exhibiting good coefficients of determination. Statistical analysis of the results obtained showed no significant difference between the proposed methodologies and the official reported methods, as evidenced by the t-test and variance ratio at a 95% confidence level. The results of this study demonstrate the applicability of the instrument for simple, accurate, precise, fast, in situ and low-cost colorimetric analysis of drugs in pharmaceutical products.This article describes the application and performance of an inexpensive, simple and portable device for colorimetric quantitative determination of drugs in pharmaceutical preparations. The sensor is a light detector resistor (LDR) incorporated into a bla513699708CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)sem informaçãosem informaçãoWe would like to thank the FUNDUNESP, CAPES and FAPESP Foundations (Brazil) for financial support and Prof. Adriana V. Rossi for donating the prototype of the portable electrochemical device used in this stud

Spectrophotometric determination of paracetamol in pharmaceuticals using microwave-assisted hydrolysis and a micellar medium

A new spectrophotometric method employing a micellar medium is proposed for the determination of paracetamol in pharmaceuticals. The method is based on the acid hydrolysis of paracetamol to p-aminophenol (PAP), which under acidic conditions reacts with p-dimethylaminocinnamaldehyde (pDAC), producing a red compound (λmax = 530 nm). This reaction can be enhanced five-fold in the presence of sodium dodecyl sulfate (SDS). The effects of all the parameters involved in both the hydrolysis step and the derivatization reaction were investigated using experimental design methodologies. The method presented a linear range of 0.2 to 3.9 μg mL–1 and an excellent correlation coefficient (r = 0.9996). The limit of detection was estimated to be 30.0 μg/L. The technique was successfully applied for the determination of paracetamol in commercial brands of pharmaceuticals. No interferences from the excipients commonly used in commercial formulations were observed, and the results obtained compared favorably with measurements made using the United States Pharmacopeia procedure, at a 95 % confidence level.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Determinação espectrofotométrica por injeção em fluxo de glifosato em formulações comerciais de herbicidas

A flow injection spectrophotometric procedure for the determination of glyphosate in commercial formulations of herbicides is proposed. The determination is based on the reaction of glyphosate and p-dimethylaminocinnamaldehyde, in acid medium, yielding a colored compound (l máx = 495 nm). Under optimal conditions, Beer's law is obeyed in a concentration range 40-640 mg mL-1 with a correlation coefficient of 0.9996. The detection limit was 8.60 mg mL-1 for glyphosate. The method was successfully applied for the determination of glyphosate in commercial formulations of herbicides. Recovery of glyphosate from various commercial samples of herbicides range from 91.0 to 110%

Spectrophotometric determination of captopril through charge transfer complex formation using fractional factorial and central composite design

A new spectrophotometric method was developed for the determination of captopril (n donor) through charge transfer complex formation with p-chloranil (π acceptor). The different experimental parameters that affect the absorbance intensity were carefully studied. Thus, these parameters were optimized using chemometric methods of fractional factorial and central composite design. At the optimum reaction conditions, the rectilinear calibration graphs were obtained in the concentration range 1.86 x 10-4 to 7.38 x 10-4 mol/L captopril with an excellent correlation coefficient (r = 0.9996). The proposed procedure could be applied successfully for the determination of the investigated drug in their pharmaceutical dosage forms with a good precision and accuracy compared to official and reported method as revealed by F- and t-tests at 95 % confidence level. No interference was observed from common excipients in formulations.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Microbiopolítica e regulação sanitária: desacordos entre ciência e saberes locais na produção dos queijos minas artesanais

Este artigo analisa a relação da produção de queijos artesanais em Minas Gerais com imposições da regulação sanitária, configuradas em instrumentos e mecanismos de biossegurança, conformados em mercados internacionais, que constroem uma imagem da produção de queijos feitos nas roças, fortemente enraizados culturalmente, como “atrasada” e “anti-higiênica”. As normas sanitárias exigem a contratação de responsáveis técnicos (engenheiros de alimentos, veterinários, nutricionistas) e consideram a formação técnica e a produção em moldes industriais como intrinsecamente mais seguras. E, em sentido contrário, criam suspeitas que populações camponesas estejam produzindo alimentos contaminados e inseguros. Ao converterem seres microscópicos em ameaça à sociedade, tais normas se constroem com uma microbiopolítica, constituindo-se como fonte de poder que associa moralmente pobreza e risco. E criam barreiras à comercialização das produções camponesas, interferindo em seus modos de vida. Baseado em trabalhos etnográficos, o artigo aborda como essas populações interagem com algumas das prescrições das normas sanitárias e conhecimentos técnico-científicos, que chegam a elas através da atividade de fiscais sanitários e de técnicos ligados à extensão rural.This article focuses on the relations between artisanal cheese production in Minas Gerais and the imposition of bio-safety policies and practices that have been structures in international markets and global science structures. It analyzes how sanitary regulation has contributed for an image of cheese production in the countryside, with its strong cultural roots, as “archaic” and “un-hygienic”, seen with suspicion by urban and “modern” societies. The implementation this regulation presents industrial food production as more efficient and safer, at the same time building suspicions that peasants are producing contaminated and unsafe food. These sanitary norms convert microscopic beings as a threat to society and constitute a microbiopolitics that is a source of power, morally connecting poverty and risk. This process has created strong barriers to legalizing peasant products, interfering on their life ways