Loading...
Publication
Deteção eletroquímica da norfloxacina e trimetoprim em amostras de urina utilizando polímero molecularmente impresso modificado e grafeno
| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 3.75 MB | Adobe PDF |
Authors
Abstract(s)
A norfloxacina e o trimetoprim são dois antibióticos antibacterianos usados para
o tratamento de infeções urinárias, intestinais e respiratórias. A maioria dos
fármacos exige uma dosagem que garanta os níveis de segurança e eficácia de
atuação. A necessidade de dosear os medicamentos e os seus metabolitos é assim
um controlo imperioso e em muitos casos regular no tratamento de um paciente.
Neste trabalho desenvolveram-se dois sensores eletroquímicos para a deteção
da norfloxacina (NFX) e do trimetoprim (TMP), usando como superfície de suporte
o carbono vítreo. A busca de novos materiais que conferiram maior seletividade
e sensibilidade aos sistemas de deteção e por outro lado apresentem
menores riscos para o paciente quando usados em dispositivos que permitam
uma análise point-of-care, é especialmente importante e pode ser uma parte crucial
do processo de decisão clínica. Assim, os polímeros molecularmente impresos
enquadram-se nesse perfil e o seu uso tem vindo a ser cada vez mais avaliado.
A impressão molecular é uma tecnologia capaz de produzir polímeros que incorporam
as moléculas do analito e que após remoção por solventes específicos,
permitem dotá-los de locais específicos de reconhecimento estereoquímico. A seleção
do pirrol como polímero molecularmente impresso (MIP) permitiu construir
com sucesso os sensores para doseamento dos antibióticos. A fim de aumentar
a sensibilidade do método incorporou-se grafeno na superfície do elétrodo. Este
material tem vindo a ser largamente utilizado devido às suas propriedades: estrutura
molecular, condutividade elétrica e aumento da superfície são algumas das
características que mais despertam o interesse para a sua aplicação neste projeto.
Os sensores desenvolvidos foram incorporados em sistemas eletroquímicos.
Os métodos voltamétricos aplicados foram a voltametria cíclica, a voltametria de
onda quadrada e ainda a impedância. As condições de análise foram otimizadas
no que respeita à polimerização do pirrol (concentração do polímero, número
de ciclos de eletropolimerização e respetivos potenciais aplicados, tempo de incubação,
solvente de remoção do analito), ao pH da solução do fármaco, à gama
de concentrações dos antibióticos e aos parâmetros voltamétricos dos métodos de análise. Para cada um dos antibióticos um elétrodo não-impresso foi também
preparado, usando o procedimento de polimerização mas sem a presença da
molécula do analito, e foi usado como controlo.
O sensor desenvolvido para o trimetoprim foi usado no doseamento do fármaco
em amostras de urina. As amostras foram analisadas sem qualquer diluição,
apenas foram centrifugadas para remoção de proteínas e algum interferente. Os
sensores construídos apresentaram comportamento linear na gama de concentrações
entre 102 e 107 mol/L. Os resultados mostram boa precisão (desvios
padrão inferiores a 11%) e os limites de deteção foram de 8,317 e 1,307 mol/L
para a norfloxacina e o trimetoprim, respetivamente. Para validação do método
foram ainda efetuados ensaios de recuperação tendo obtido valores superiores a
94%.
The Norfloxacin and timethoprim are two antibactarial antibiotics used for treatement of urinary , intestinal and respiratory infections. The most of drugs require a dosage to ensure safety and e ectiveness levels of the performance. The necessity to dose drugs and their metabolites is thus a imperative control and in many instances in the treatment of a pacient. In this case study we developed two electrochemicals sensors to detect norfloxacina and timethoprim, using as support surface a glassy carbon. The search of the new materials that conferred great selectivity and sensibility to detection systems as well as less risks to the pacient when used in devices that allow analysis point-of-care, is specially important and can be a crucial part of clinical decision process. Thus, polymers that came of molecularly imprinted fits into this profile and their use has been incresingly evaluated. The molecular imprinting is a technology capable to produce polymers that incorporate molecules of analyte and after remotion by specific solventes, allow endow them of specifics places of stereochemical recognition. The selection of pyrrol as molecularly imprinting polymer (MIP) enable to build with sucess sensors to dosing antibiotics. To increase the method sensibility, embodied Graphene on electrode surface. This material have been widely used because of their properties: molecular structure, electric conductibility and surface increased are some caracteristics that arouse interest to aplication in this project. Developped sensors were incorporated in electrochemical systems. Voltammetric methods aplied were cyclic voltammetry, square wave voltammetry and impedance. The analysis conditions were optimized as regards the pyrrol polymerization (polymer concentration, number of cycles of electropolymerization and respective potencials applied, incubation time, solvent for analyte remotion), pH of drug solution, concentration range of antibiotics and voltammetric parameters of analyse methods. For each of one antibiotics, a non-imprinted electrode was prepared using a polymerization process but without the presence of analytic molecule, and was used as control. The developped sensor to timethoprim was used in dosage of drug in urine samples. The samples were analysed without any dilution, just were centrifuged to remove proteins and some interferents. The built sensors present a linear behaviour with concentrations range between 102 and 107 mol/L. The results show a good precision (standard desviation below a 11%) and the detection limits were 8,317 and 1,307 mol/L, to norfloxacina and trimethoprim, respectively. To method validation were made recuperation assays have been get values above 94%.
The Norfloxacin and timethoprim are two antibactarial antibiotics used for treatement of urinary , intestinal and respiratory infections. The most of drugs require a dosage to ensure safety and e ectiveness levels of the performance. The necessity to dose drugs and their metabolites is thus a imperative control and in many instances in the treatment of a pacient. In this case study we developed two electrochemicals sensors to detect norfloxacina and timethoprim, using as support surface a glassy carbon. The search of the new materials that conferred great selectivity and sensibility to detection systems as well as less risks to the pacient when used in devices that allow analysis point-of-care, is specially important and can be a crucial part of clinical decision process. Thus, polymers that came of molecularly imprinted fits into this profile and their use has been incresingly evaluated. The molecular imprinting is a technology capable to produce polymers that incorporate molecules of analyte and after remotion by specific solventes, allow endow them of specifics places of stereochemical recognition. The selection of pyrrol as molecularly imprinting polymer (MIP) enable to build with sucess sensors to dosing antibiotics. To increase the method sensibility, embodied Graphene on electrode surface. This material have been widely used because of their properties: molecular structure, electric conductibility and surface increased are some caracteristics that arouse interest to aplication in this project. Developped sensors were incorporated in electrochemical systems. Voltammetric methods aplied were cyclic voltammetry, square wave voltammetry and impedance. The analysis conditions were optimized as regards the pyrrol polymerization (polymer concentration, number of cycles of electropolymerization and respective potencials applied, incubation time, solvent for analyte remotion), pH of drug solution, concentration range of antibiotics and voltammetric parameters of analyse methods. For each of one antibiotics, a non-imprinted electrode was prepared using a polymerization process but without the presence of analytic molecule, and was used as control. The developped sensor to timethoprim was used in dosage of drug in urine samples. The samples were analysed without any dilution, just were centrifuged to remove proteins and some interferents. The built sensors present a linear behaviour with concentrations range between 102 and 107 mol/L. The results show a good precision (standard desviation below a 11%) and the detection limits were 8,317 and 1,307 mol/L, to norfloxacina and trimethoprim, respectively. To method validation were made recuperation assays have been get values above 94%.
Description
Keywords
Trimetoprim Norfloxacina Eletroquímica Polímero molecularmente impresso Grafeno Trimethoprim Norfloxacin Electrochemical Molecularly imprinting polymer Graphene
Pedagogical Context
Citation
Publisher
Instituto Politécnico do Porto. Instituto Superior de Engenharia do Porto