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.
Plasma measurements of levodopa and its major metabolites including dopamine and 3-O-methyldopa have been limited by cumbersome methods and poor sensitivity within relatively narrow ranges of plasma levels. We now report a modification of an HPLC method that permits concomitant measurements of a wide range of concentrations of levodopa, dopamine (DA), carbidopa, 3-O-methyldopa (3-OMD) and 3,4-dihydroxyphenyl acetic acid (DOPAC) from one HPLC injection. The recoveries ranged from 77 to 107% with an intra-day precision around 5% (CV) and inter-day CV's about 10-20%. This validated method will simplify pharmacokinetic studies of levodopa and its metabolites for mechanistic studies or therapeutic clinical monitoring which play a crucial role in development of strategies to prolong motor benefits from individual doses and reduce involuntary movements called dykinesias.
Department of Neurology, Washington University in St. Louis, St. Louis, MO, USA.
Morvarid
M
Karimi
Juanita L
JL
Carl
Susan
S
Loftin
Joel S
JS
Perlmutter
D015102:3,4-Dihydroxyphenylacetic Acid / Q000097:blood*; D002138:Calibration; D002230:Carbidopa / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004298:Dopamine / Q000097:blood*; D004563:Electrochemistry / Q000379:methods*; D007980:Levodopa / Q000097:blood* / Q000493:pharmacokinetics; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000097:blood
D015102:3,4-Dihydroxyphenylacetic Acid; D014443:Tyrosine; D007980:Levodopa; D002230:Carbidopa; C008404:3-methoxytyrosine; D004298:Dopamine