Determination of levodopa methyl ester and its metabolites in rat serum by CZE with amperometric detection

Wang, J.; Zhou, Yun; Wang, A. F.; Zhang, S. H.; Lin, Ning; He, Pingang; Fang, Yuzhi

doi:10.1007/s00216-005-3202-8

Cited by 5 publications

(3 citation statements)

References 10 publications

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“…We measured 2 ml homogenate precisely into centrifuge tube, then put into the same volume protein precipitator, mixed for 2 minutes, centrifuge treating it for 15 minutes 4000 rpm, supernatant fluid was filtered with 0.45 mm membrane, 10 ml subsequent filtrate was the injected sample [5].…”

Section: Preparation and Processing Of Homogenate Of Rabbit Brain Tissuementioning

confidence: 99%

Assay of Levodopa in Brain by CE

Xu¹,

Sun²,

Xu³

et al. 2007

Artificial Cells, Blood Substitutes, and Biotechnology

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This article reports a CE (capillary electrophoresis) method for the determination of Levodopa (L-DP) in rabbit brain tissue. L-DP was separated and determined on a fused quartz capillary (75 microm ID, 75 cm length, 50 cm effective length, Beckman Co.) with a mobile phase of phosphate buffer (pH = 2.5, 20 mmol/L THAM, 3% carboxymethyl-beta-cyclodextrin), sample pressure 0.6 kPa x 6 s, separation voltage 20 KV, detected at 280 nm and temperature 25 degrees C. The calibration curve was linear (r = 0.9999, n = 6) within the range of 0.5-16 microg/ml for L-DP. The recovery ratio was 87.87%. The mean relative standard deviation (RSD) was 2.73% (n = 5). This method is convenient, rapid, accurate, and brings about good recovery; it can be used for content determination of levodopa in rabbit brain tissue.

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Section: Preparation and Processing Of Homogenate Of Rabbit Brain Tissuementioning

confidence: 99%

Assay of Levodopa in Brain by CE

Xu¹,

Sun²,

Xu³

et al. 2007

Artificial Cells, Blood Substitutes, and Biotechnology

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“…There are currently several analytical methods for the determination of L‐DOPA or Tyr, including HPLC , TLC , flow injection analysis , CE , and microchip capillary electrophoresis (MCE) . And, various detection techniques, such as UV , fluorescence , chemiluminescence , electrochemical detection (ECD) , and MS , were reported. Moreover, enantiomeric separation of DOPA has also been presented .…”

Section: Introductionmentioning

confidence: 99%

Development of a microchip-pulsed electrochemical method for rapid determination of L-DOPA and tyrosine inMucuna pruriens

Chen

Yang

et al. 2013

J. Sep. Science

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L-3,4-dihydroxyphenylalanine (L-DOPA) is a well-recognized therapeutic compound to Parkinson's disease. Tyrosine is a precursor for the biosynthesis of L-DOPA, both of which are widely found in traditional medicinal material, Mucuna pruriens. In this paper, we described a validated novel analytical method based on microchip capillary electrophoresis with pulsed electrochemical detection for the simultaneous measurement of L-DOPA and tyrosine in M. pruriens. This protocol adopted end-channel amperometric detection using platinum disk electrode on a homemade glass/polydimethylsiloxane electrophoresis microchip. The background buffer consisted of 10 mM borate (pH 9.5) and 0.02 mM cetyltrimethylammonium bromide, which can produce an effective resolution for the two analytes. In the optimal condition, sufficient electrophoretic separation and sensitive detection for the target analytes can be realized within 60 s. Both tyrosine and L-DOPA yielded linear response in the concentration range of 5.0-400 μM (R(2) > 0.99), and the LOD were 0.79 and 1.1 μM, respectively. The accuracy and precision of the established method were favorable. The present method shows several merits such as facile apparatus, high speed, low cost and minimal pollution, and provides a means for the pharmacologically active ingredients assay in M. pruriens.

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“…There are only four reports on determination of LDME in human biological fluids (Fix et al, 1989;Koshimura et al, 1992;Rondelli et al, 1994;Wang et al, 2005) and no publications were found dealing with the LC analysis of LDME for determination of the purity, quantitative determination or enantiomeric separation. Several techniques have been reported in the literatures for the determination of L-DOPA individually in pharmaceutical formulations such as ion-selective electrode (Badawy et al, 1996), voltammetry (Biryol et al, 1995), spectrofluorimetry (Honda et al, 1983) and chromatography methods (Wu, 2000;Schieffer, 1979;Tolokan et al, 1997;Dolezalova and Tkaczykova,…”

mentioning

confidence: 99%

Determination, purity assessment and chiral separation of levodopa methyl ester in bulk and formulation pharmaceuticals

Wang

Fang

2006

Biomedical Chromatography

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A sensitive, reliable and reproducible HPLC method with electrochemical detection (HPLC-ECD) has been developed for the separation and quantification of levodopa methyl ester (LDME) and its impurities such as levodopa (l-DOPA), 3-methoxytyrosine (MTS) and l-tyrosine (TS) in bulk drug and pharmaceutical dosage form. The separation was performed on an LC18 column by isocratic elution with methanol-acetonitrile-50 mm potassium dihydrogen phosphate (8:2:90, v/v/v) containing 5 mm sodium 1-hexanesulfonate, 5 mm EDTA and 5 mm sodium chloride, adjusted with phosphoric acid to a pH of 3.2 as mobile phase. The correlation coefficients of linear regression for LDME, L-DOPA, MTS and TS were more than 0.999. The detection limits for L-DOPA, MTS and TS were 3.15, 2.04 and 2.88 ng/mL, respectively. The precision was checked in terms of F-test variance ratio using potentiometric titration as reference. The separation of dopa methyl ester enantiomers by chiral chromatography is also described. This method is capable of separating the two enantiomers with a selection of 1.4 and a resolution of 8.4. Both methods were found to be stable and useful in the quality control of the bulk material and formulations.

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Determination of levodopa methyl ester and its metabolites in rat serum by CZE with amperometric detection

Cited by 5 publications

References 10 publications

Assay of Levodopa in Brain by CE

Assay of Levodopa in Brain by CE

Development of a microchip-pulsed electrochemical method for rapid determination of L-DOPA and tyrosine inMucuna pruriens

Determination, purity assessment and chiral separation of levodopa methyl ester in bulk and formulation pharmaceuticals

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