A simple spectrophotometric method for the determination of methyldopa using p-chloranil in the presence of hydrogen peroxide

Detalhes bibliográficos
Autor(a) principal: Gotardo, M. A. [UNESP]
Data de Publicação: 2008
Outros Autores: Lima, L. S. [UNESP], Sequinel, R. [UNESP], Rufino, J. L. [UNESP], Pezza, L. [UNESP], Pezza, H. R. [UNESP]
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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spelling 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
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