Simultaneous determination of levodopa methyl ester, levodopa, 3-O-methyldopa and dopamine in plasma by high-performance liquid chromatography with electrochemical detection

Rondelli, Ivano; Acerbi, Daniela; Mariotti, Fabrizia; Ventura, Paolo

doi:10.1016/0378-4347(93)e0411-i

Cited by 43 publications

(22 citation statements)

References 19 publications

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“…Levodopa Measurements. Levodopa and carbidopa levels were measured by using HPLC with electrochemical detection following a modified version of published methods (27,28). We added an internal standard, 3,4-dihydrobenzylamine (DHBA), to simplify quantification.…”

Section: Methodsmentioning

confidence: 99%

Altered thalamic response to levodopa in Parkinson’s patients with dopa-induced dyskinesias

Hershey

Black

Stambuk

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

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Parkinson's disease (PD) is a progressive neurologic condition characterized by tremor, slowness, stiffness, and unstable posture. Degeneration of dopamineproducing neurons in the substantia nigra causes PD. Treatment with levodopa, a precursor of dopamine, initially ameliorates the clinical manifestations of PD. However, chronic levodopa treatment can produce severe involuntary movements (so-called dopa-induced dyskinesias or DID), limiting treatment. Pallidotomy, placement of a surgical lesion in the internal segment of the globus pallidus, reduces DID. Because this result is inconsistent with current theories of both basal ganglia function and DID, it prompted us to investigate the brain's response to levodopa. We measured regional cerebral blood f low response to levodopa with positron-emission tomography in 6 PD patients with DID, 10 chronically treated PD patients without DID, 17 dopa-naïve PD patients, and 11 normals. The dose of levodopa was chosen to produce clinical benefit without inducing DID. This strategy allowed us to examine the brain response to levodopa across groups without the confounding effect of differences in motor behavior. We found that the DID group had a significantly greater response in ventrolateral thalamus than the other groups. This was associated with decreased activity in primary motor cortex. These findings are consistent with increased inhibitory output from the internal segment of the globus pallidus to thalamus after levodopa administration. They provide a physiological explanation for the clinical efficacy of pallidotomy and new insights into the physiology of the basal ganglia.

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Section: Methodsmentioning

confidence: 99%

Altered thalamic response to levodopa in Parkinson’s patients with dopa-induced dyskinesias

Hershey

Black

Stambuk

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

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“…3 On the other hand, catecholamines are present in relatively large amounts in pharmaceutical formulations and much effort has been devoted to the development of simple, rapid, accurate and precise analytical methods. Of those, the most employed methods include spectrophotometry, [4][5][6] high performance liquid chromatography (HPLC) with electrochemical detection [7][8][9][10][11][12][13][14][15] and capillary zone electrophoresis (CZE) with electrochemical detection. [16][17][18][19][20] To the best of our knowledge, there is only one differential pulse voltammetry (DPV) procedure in the literature using a glassy carbon electrode for the determination of L-dopa and a glassy carbon electrode coated with Nafion film for the determination of carbidopa.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous differential pulse voltammetric determination of L-dopa and carbidopa in pharmaceuticals using a carbon paste electrode modified with lead dioxide immobilized in a polyester resin

Melo¹,

Seleghim²,

Polito³

et al. 2007

J. Braz. Chem. Soc.

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Um eletrodo de pasta de carbono modificado com dióxido de chumbo imobilizado em uma resina de poliéster foi desenvolvido para a determinação voltamétrica de pulso diferencial simultânea de L-dopa e carbidopa em formulações farmacêuticas. As curvas analíticas foram lineares em uma faixa de concentração de 2,6 × 10 -4 a 1,2 × 10 -3 mol L -1 e de 3,2 × 10 -5 a 1,5 × 10 -4 mol L -1 para L-dopa e carbidopa, respectivamente. Os limites de detecção foram 2,5 × 10 -5 mol L -1 e 3,7 × 10 -6 mol L -1 para L-dopa e carbidopa, respectivamente e as recuperações de L-dopa e carbidopa em duas amostras variaram de 98,1 a 103%. Os desvios padrão relativos foram menores que 2,5% para soluções 1,2 × 10 -4 e 1,2 × 10 -3 mol L -1 dessas catecolaminas e os resultados obtidos para L-dopa e carbidopa em formulações farmacêuticas usando o procedimento voltamétrico proposto estão em boa concordância com os valores rotulados ou com aqueles teores determinados empregando-se um procedimento enzimático a um nível de confiança de 95%.A carbon paste electrode modified with lead dioxide immobilized in a polyester resin has been developed for simultaneous differential pulse voltammetric determination of L-dopa and carbidopa in pharmaceutical formulations. The analytical curves were linear in the concentration ranges from 2.6 × 10 -4 to 1.2 × 10 -3 mol L -1 and from 3.2 × 10 -5 to 1.5 × 10 -4 mol L -1 for L-dopa and carbidopa, respectively. The detection limits were 2.5 × 10 -5 mol L -1 and 3.7 × 10 -6 mol L -1 for L-dopa and carbidopa, respectively and recoveries of L-dopa and carbidopa from two samples ranged from 98.1 to 103% of the added amount. The relative standard deviations were lower than 2.5% for 1.2 × 10 -4 and 1.2 × 10 -3 mol L -1 of these catecholamines solutions and the results obtained for L-dopa and carbidopa in pharmaceutical formulations using the proposed voltammetric procedure are in close agreement with the labeled values and/or those obtained using an enzymatic method at the 95% confidence level.Keywords: L-dopa, carbidopa, differential pulse voltammetry (DPV), carbon paste electrode modified with lead dioxide 3 On the other hand, catecholamines are present in relatively large amounts in pharmaceutical formulations and much effort has been devoted to the development of simple, rapid, accurate and precise analytical methods. Of those, the most employed methods include spectrophotometry, [4][5][6] high performance liquid chromatography (HPLC) with electrochemical detection [7][8][9][10][11][12][13][14][15] and capillary zone electrophoresis (CZE) with electrochemical detection. [16][17][18][19][20] To the best of our knowledge, there is only one differential pulse voltammetry (DPV) procedure in the literature using a glassy carbon electrode for the determination of L-dopa and a glassy carbon electrode coated with Nafion film for the determination of carbidopa. 21DPV has been demonstrated to be a useful technique for the determination of many molecules of biological importance. 22 The high selectivity, sensitivity, accuracy, pr...

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“…Similar to the technique of Rondelli et al [9] our HPLC method detects clinically relevant minimal amounts of plasma levodopa and its related compounds and yet maintains accuracy across a wider range of concentrations than previous methods [11,12]. However, our approach also permits measurement of DOPAC and carbidopa in the same HPLC run.…”

Section: Discussionmentioning

confidence: 63%

Modified high-performance liquid chromatography with electrochemical detection method for plasma measurement of levodopa, 3-O-methyldopa, dopamine, carbidopa and 3,4-dihydroxyphenyl acetic acid

Karimi

Carl

Loftin

et al. 2006

Journal of Chromatography B

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Simultaneous determination of levodopa methyl ester, levodopa, 3-O-methyldopa and dopamine in plasma by high-performance liquid chromatography with electrochemical detection

Cited by 43 publications

References 19 publications

Altered thalamic response to levodopa in Parkinson’s patients with dopa-induced dyskinesias

Altered thalamic response to levodopa in Parkinson’s patients with dopa-induced dyskinesias

Simultaneous differential pulse voltammetric determination of L-dopa and carbidopa in pharmaceuticals using a carbon paste electrode modified with lead dioxide immobilized in a polyester resin

Modified high-performance liquid chromatography with electrochemical detection method for plasma measurement of levodopa, 3-O-methyldopa, dopamine, carbidopa and 3,4-dihydroxyphenyl acetic acid

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