A simple spectrophotometric method for the determination of methyldopa using p-chloranil in the presence of hydrogen peroxide
Autor(a) principal: | |
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Data de Publicação: | 2008 |
Outros Autores: | , , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UNESP |
Texto Completo: | http://dx.doi.org/10.1590/S0100-46702008000300001 http://hdl.handle.net/11449/211191 |
Resumo: | A simple, rapid and sensitive spectrophotometric method has been developed for the determination of methyldopa in pharmaceutical formulations. The method is based on the reaction between tetrachloro-p-benzoquinone (p-chloranil) and methyldopa, accelerated by hydrogen peroxide (H2O2), producing a violet-red compound (λmax = 535 nm) at ambient temperature (25.0 ± 0.2 ºC). Experimental design methodologies were used to optimize the measurement conditions. Beer's law is obeyed in a concentration range from 2.10 x 10-4 to 2.48 x 10-3 mol L-1 (r = 0.9997). The limit of detection was 7.55 x 10-6 mol L-1 and the limit of quantification was 2.52 x 10-5 mol L-1. The intraday precision and interday precision were studied for 10 replicate analyses of 1.59 x 10-3 mol L-1 methyldopa solution and the respective coefficients of variation were 0.7 and 1.1 %. The proposed method was successfully applied to the determination of methyldopa in commercial brands of pharmaceuticals. No interferences were observed from the common excipients in the formulations. The results obtained by the proposed method were favorably compared with those given by the Brazilian Pharmacopoeia procedure at 95 % confidence level. |
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A simple spectrophotometric method for the determination of methyldopa using p-chloranil in the presence of hydrogen peroxideUm método espectrofotométrico simples para a determinação de metildopa usando p-cloranil na presença de peróxido de hidrogêniospectrophotometryp-chloranilhydrogen peroxidemethyldopapharmaceutical formulationsespectrofotometriap-cloranilperóxido de hidrogêniometildopaformulações farmacêuticasA simple, rapid and sensitive spectrophotometric method has been developed for the determination of methyldopa in pharmaceutical formulations. The method is based on the reaction between tetrachloro-p-benzoquinone (p-chloranil) and methyldopa, accelerated by hydrogen peroxide (H2O2), producing a violet-red compound (λmax = 535 nm) at ambient temperature (25.0 ± 0.2 ºC). Experimental design methodologies were used to optimize the measurement conditions. Beer's law is obeyed in a concentration range from 2.10 x 10-4 to 2.48 x 10-3 mol L-1 (r = 0.9997). The limit of detection was 7.55 x 10-6 mol L-1 and the limit of quantification was 2.52 x 10-5 mol L-1. The intraday precision and interday precision were studied for 10 replicate analyses of 1.59 x 10-3 mol L-1 methyldopa solution and the respective coefficients of variation were 0.7 and 1.1 %. The proposed method was successfully applied to the determination of methyldopa in commercial brands of pharmaceuticals. No interferences were observed from the common excipients in the formulations. The results obtained by the proposed method were favorably compared with those given by the Brazilian Pharmacopoeia procedure at 95 % confidence level.Este trabalho descreve um método espectrofotométrico simples, rápido e sensível para a determinação de metildopa em formulações farmacêuticas. O método é baseado na reação entre tetracloro-p-benzoquinona (p-cloranil) e metildopa, a qual é acelerada por peróxido de hidrogênio (H2O2), produzindo um composto vermelho-violeta (λmax = 535 nm) à temperatura ambiente (25,0 ± 0,2 ºC). As melhores condições para a reação foram obtidas por planejamento experimental. A lei de Beer é obedecida em um intervalo de concentração de 2,10 x 10-4 to 2,48 x 10-3 mol L-1 (r = 0,9997). O limite de detecção determinado foi de 7,55 x 10-6 mol L-1 e o limite de quantificação foi de 2,52 x 10-5 mol L-1. A precisão intradia e interdia do método proposto foram determinadas pela análise em decuplicata (n=10) de uma solução de metildopa 1,59 x 10-3 mol L-1 e apresentaram coeficientes de variação de 0,7 e 1,1%, respectivamente. O método proposto foi aplicado com sucesso na determinação de metildopa em diferentes marcas de medicamentos. Os resultados obtidos pelo método proposto estiveram em boa concordância com aqueles obtidos pelo método da Farmacopéia Brasileira em um nível de confiança de 95%.Universidade Estadual Paulista, Chemistry Institute of AraraquaraUniversidade Estadual Paulista, Chemistry Institute of AraraquaraFundação Editora da Universidade Estadual Paulista Júlio de Mesquita Filho - UNESPUniversidade Estadual Paulista (Unesp)Gotardo, M. A. [UNESP]Lima, L. S. [UNESP]Sequinel, R. [UNESP]Rufino, J. L. [UNESP]Pezza, L. [UNESP]Pezza, H. R. [UNESP]2021-07-14T10:20:37Z2021-07-14T10:20:37Z2008info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/article7-12application/pdfhttp://dx.doi.org/10.1590/S0100-46702008000300001Eclética Química. São Paulo, SP, Brazil: Fundação Editora da Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP, v. 33, n. 3, p. 7-12, 2008.0100-46701678-4618http://hdl.handle.net/11449/21119110.1590/S0100-46702008000300001S0100-46702008000300001S0100-46702008000300001.pdfSciELOreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPengEclética Químicainfo:eu-repo/semantics/openAccess2023-12-14T06:22:08Zoai:repositorio.unesp.br:11449/211191Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462024-08-05T20:19:48.578444Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false |
dc.title.none.fl_str_mv |
A simple spectrophotometric method for the determination of methyldopa using p-chloranil in the presence of hydrogen peroxide Um método espectrofotométrico simples para a determinação de metildopa usando p-cloranil na presença de peróxido de hidrogênio |
title |
A simple spectrophotometric method for the determination of methyldopa using p-chloranil in the presence of hydrogen peroxide |
spellingShingle |
A simple spectrophotometric method for the determination of methyldopa using p-chloranil in the presence of hydrogen peroxide Gotardo, M. A. [UNESP] spectrophotometry p-chloranil hydrogen peroxide methyldopa pharmaceutical formulations espectrofotometria p-cloranil peróxido de hidrogênio metildopa formulações farmacêuticas |
title_short |
A simple spectrophotometric method for the determination of methyldopa using p-chloranil in the presence of hydrogen peroxide |
title_full |
A simple spectrophotometric method for the determination of methyldopa using p-chloranil in the presence of hydrogen peroxide |
title_fullStr |
A simple spectrophotometric method for the determination of methyldopa using p-chloranil in the presence of hydrogen peroxide |
title_full_unstemmed |
A simple spectrophotometric method for the determination of methyldopa using p-chloranil in the presence of hydrogen peroxide |
title_sort |
A simple spectrophotometric method for the determination of methyldopa using p-chloranil in the presence of hydrogen peroxide |
author |
Gotardo, M. A. [UNESP] |
author_facet |
Gotardo, M. A. [UNESP] Lima, L. S. [UNESP] Sequinel, R. [UNESP] Rufino, J. L. [UNESP] Pezza, L. [UNESP] Pezza, H. R. [UNESP] |
author_role |
author |
author2 |
Lima, L. S. [UNESP] Sequinel, R. [UNESP] Rufino, J. L. [UNESP] Pezza, L. [UNESP] Pezza, H. R. [UNESP] |
author2_role |
author author author author author |
dc.contributor.none.fl_str_mv |
Universidade Estadual Paulista (Unesp) |
dc.contributor.author.fl_str_mv |
Gotardo, M. A. [UNESP] Lima, L. S. [UNESP] Sequinel, R. [UNESP] Rufino, J. L. [UNESP] Pezza, L. [UNESP] Pezza, H. R. [UNESP] |
dc.subject.por.fl_str_mv |
spectrophotometry p-chloranil hydrogen peroxide methyldopa pharmaceutical formulations espectrofotometria p-cloranil peróxido de hidrogênio metildopa formulações farmacêuticas |
topic |
spectrophotometry p-chloranil hydrogen peroxide methyldopa pharmaceutical formulations espectrofotometria p-cloranil peróxido de hidrogênio metildopa formulações farmacêuticas |
description |
A simple, rapid and sensitive spectrophotometric method has been developed for the determination of methyldopa in pharmaceutical formulations. The method is based on the reaction between tetrachloro-p-benzoquinone (p-chloranil) and methyldopa, accelerated by hydrogen peroxide (H2O2), producing a violet-red compound (λmax = 535 nm) at ambient temperature (25.0 ± 0.2 ºC). Experimental design methodologies were used to optimize the measurement conditions. Beer's law is obeyed in a concentration range from 2.10 x 10-4 to 2.48 x 10-3 mol L-1 (r = 0.9997). The limit of detection was 7.55 x 10-6 mol L-1 and the limit of quantification was 2.52 x 10-5 mol L-1. The intraday precision and interday precision were studied for 10 replicate analyses of 1.59 x 10-3 mol L-1 methyldopa solution and the respective coefficients of variation were 0.7 and 1.1 %. The proposed method was successfully applied to the determination of methyldopa in commercial brands of pharmaceuticals. No interferences were observed from the common excipients in the formulations. The results obtained by the proposed method were favorably compared with those given by the Brazilian Pharmacopoeia procedure at 95 % confidence level. |
publishDate |
2008 |
dc.date.none.fl_str_mv |
2008 2021-07-14T10:20:37Z 2021-07-14T10:20:37Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://dx.doi.org/10.1590/S0100-46702008000300001 Eclética Química. São Paulo, SP, Brazil: Fundação Editora da Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP, v. 33, n. 3, p. 7-12, 2008. 0100-4670 1678-4618 http://hdl.handle.net/11449/211191 10.1590/S0100-46702008000300001 S0100-46702008000300001 S0100-46702008000300001.pdf |
url |
http://dx.doi.org/10.1590/S0100-46702008000300001 http://hdl.handle.net/11449/211191 |
identifier_str_mv |
Eclética Química. São Paulo, SP, Brazil: Fundação Editora da Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP, v. 33, n. 3, p. 7-12, 2008. 0100-4670 1678-4618 10.1590/S0100-46702008000300001 S0100-46702008000300001 S0100-46702008000300001.pdf |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Eclética Química |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
7-12 application/pdf |
dc.publisher.none.fl_str_mv |
Fundação Editora da Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP |
publisher.none.fl_str_mv |
Fundação Editora da Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP |
dc.source.none.fl_str_mv |
SciELO reponame:Repositório Institucional da UNESP instname:Universidade Estadual Paulista (UNESP) instacron:UNESP |
instname_str |
Universidade Estadual Paulista (UNESP) |
instacron_str |
UNESP |
institution |
UNESP |
reponame_str |
Repositório Institucional da UNESP |
collection |
Repositório Institucional da UNESP |
repository.name.fl_str_mv |
Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP) |
repository.mail.fl_str_mv |
|
_version_ |
1808129189314822144 |