Simultaneous determination of levodopa, carbidopa, 3-O-methyldopa and dopamine in plasma using high-performance liquid chromatography with electrochemical detection.
An analytical method is described which allows a fast, reliable and precise determination of levodopa and its metabolises 3-O-methyldopa and dopamine, as well as the peripheral aromatic amino acid decarboxylase inhibitor carbidopa, in a single 1 ml plasma sample of Parkinsonian patients. The compounds are quantitatively isolated on small Sephadex G-10 columns and determined by HPLC with electrochemical detection. Dihydroxybenzylamine or alpha-methyldopa are used as the internal standard. An example of therapeutic drug monitoring in a patient with fluctuations in motor performances is given. It is confirmed that interference with absorption of levodopa from the stomach by food can be partly responsible for these observed fluctuations.
Michotte
Y
Y
Pharmaceutical Institute, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium.
Moors
M
M
Deleu
D
D
Herregodts
P
P
Ebinger
G
G