Determination of levodopa in human plasma by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS): application to a bioequivalence study

Martins, Heliana Figueiredo; Pinto, Douglas Pereira; Nascimento, A. R. do; Marques, Anna S. F.; Amendoeira, C.

doi:10.1590/s0100-40422013000100028

Cited by 20 publications

(13 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For HPLC-UV analysis, each of LTG, TX and L-Dopa and their respective IS solutions spiked at high intensity, with no interfering endogenous peaks or noise observed, indicating method specificity. Retention time recorded for each in rat plasma and brain homogenate, came in accordance with similar data reported in literature (Martins et al, 2013). All standard calibration curves assessed in rat plasma and brain homogenate indicated linear relation between drug-plasma and/or drug-brain concentration and the input concentration, with coefficient of determination (R 2 ) approaching unity; inferring linearity.…”

Section: Resultssupporting

confidence: 90%

Brain targeting stealth lipomers of combined antiepileptic-anti-inflammatory drugs as alternative therapy for conventional anti-Parkinson’s

Higazy

2020

Saudi Pharmaceutical Journal

View full text Add to dashboard Cite

show abstract

Section: Resultssupporting

confidence: 90%

Brain targeting stealth lipomers of combined antiepileptic-anti-inflammatory drugs as alternative therapy for conventional anti-Parkinson’s

Higazy

2020

Saudi Pharmaceutical Journal

View full text Add to dashboard Cite

show abstract

“…The signal intensity of each analyte was evaluated via the direct infusion of the standard solutions (200 ng/mL of LD, 50 ng/mL of CBD and 200 ng/mL of EC) prepared by dissolving and diluting in mobile phases B and A as described in section 2.3, using different combinations of formic acid, ammonium acetate and ammonium formate as additives. LC/MS/MS methods for the determination of these analytes have been previously reported in the literature, and the most common additive used for ion generation is formic acid 26–29 . This additive left no residue in the ion source of the mass spectrometer and was found to be the best mobile phase additive for this study, with the best signal intensity being observed for all compounds with 0.5% formic acid.…”

Section: Resultsmentioning

confidence: 88%

“…There are also some groups which use coulometric or electrochemical detectors integrated with HPLC to measure these compounds 20–24 . MS/MS has been used to achieve lower detection levels for compounds of interest by employing fast gradients with relatively short columns for detection in biological matrices 25–32 …”

Section: Introductionmentioning

confidence: 99%

A rapid liquid chromatography/tandem mass spectrometry method for simultaneous determination of levodopa, carbidopa, entacapone and their six related compounds in film‐coated tablets

Burmaoğlu

Aslan

2020

Rapid Comm Mass Spectrometry

View full text Add to dashboard Cite

Rationale:A liquid chromatography/tandem mass spectrometry (LC/MS/MS) method has been developed and validated to determine levodopa, carbidopa, entacapone, and corresponding six related substanceslevodopa impurity B, levodopa impurity C, methyldopa, methylcarbidopa, entacapone impurity C, and entacapone impurity Ain film-coated tablets for the first time.Methods: Chromatographic separation was achieved with a gradient elution by using a C18 column, a mobile phase containing 0.5% formic acid in water and 0.5% formic acid in methanol. The mobile phase flow rate was 0.5 mL min −1 . The UV detector was set at 280 nm and the triple quadrupole mass spectrometer was used in multiple reaction monitoring (MRM) mode. Results:The limit of detection (LOD) and limit of quantification (LOQ) results were 1.3 and 3.94 ng mL −1 for levodopa impurity B; 5.26 and 15.9 ng mL −1 for levodopa impurity C; 0.833 and 2.53 ng mL −1 for methyldopa; 3.31 and 10.0 ng mL −1 for methylcarbidopa; 1.67 and 5.06 ng mL −1 for entacapone impurity C; and 0.61 and 1.86 ng mL −1 for entacapone impurity A. Conclusions:The method was rapid, linear, accurate, and reproducible. The LC/MS/MS method that was developed to determine the related substances and assay of levodopa, carbidopa, and entacapone can be used to evaluate the quality of regular samples in the pharmaceutical industry. It can be also used to test the stability of samples.

show abstract

“…This dosage was selected based on previous studies that have also used L-DOPA to investigate similar Markov decision making tasks [16,27]. About 45 minutes post-administration, during which L-DOPA plasma levels were expected to peak [28], participants completed the two-step task. The fMRI task took about 36 minutes.…”

Section: Overall Study Designmentioning

confidence: 99%

Individual differences in dopamine function underlying the balance between model-based and model-free control

Lee

Deserno

Kroemer

et al. 2019

Preprint

View full text Add to dashboard Cite

Reinforcement learning involves a balance between model-free (MF) and model-based (MB) systems. Recent studies suggest that individuals with either pharmacologically enhanced levels of dopamine (DA) or higher baseline levels of DA exhibit more MB control. However, it remains unknown whether such pharmacological effects depend on baseline DA.Here, we investigated whether effects of L-DOPA on the balance of MB/MF control depend on ventral striatal baseline DA. Sixty participants had two functional magnetic resonance imaging (fMRI) scans while performing a two-stage sequential decision-making task under 150 mg L-DOPA or placebo (counterbalanced), followed by a 4-hour 18 F-DOPA positron emission tomography (PET) scan (on a separate occasion).We found an interaction between baseline DA levels and L-DOPA induced changes in MB control. Individuals with higher baseline DA levels showed a greater L-DOPA induced enhancement in MB control. Surprisingly, we found a corresponding drug-by-baseline DA interaction on MF, but not MB learning signals in the ventromedial prefrontal cortex. We did not find a significant interaction between baseline DA levels and L-DOPA effects on MF control or MB/MF balance.In sum, our findings point to a baseline dependency of L-DOPA effects on differential aspects of MB and MF control. Individual differences in DA washout may be an important moderator of L-DOPA effects. Overall, our findings complement the general notion where higher DA levels is related to a greater reliance on MB control. Although the relationship between phasic DA firing and MF learning is conventionally assumed in the animal literature, the relationship between DA and MF control is not as straightforward and requires further clarification.

show abstract

Determination of levodopa in human plasma by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS): application to a bioequivalence study

Cited by 20 publications

References 18 publications

Brain targeting stealth lipomers of combined antiepileptic-anti-inflammatory drugs as alternative therapy for conventional anti-Parkinson’s

Brain targeting stealth lipomers of combined antiepileptic-anti-inflammatory drugs as alternative therapy for conventional anti-Parkinson’s

A rapid liquid chromatography/tandem mass spectrometry method for simultaneous determination of levodopa, carbidopa, entacapone and their six related compounds in film‐coated tablets

Individual differences in dopamine function underlying the balance between model-based and model-free control

Contact Info

Product

Resources

About