Various high-performance liquid chromatographic (HPLC) methods for the determination of plasma levels of L-dopa and of its metabolite, 3-O- methyldopa (3-OMD), have been previously described. In this study, we report a modification of these methods, that enables the assay of these two compounds in platelets and plasma obtained from the same sample of whole blood. Reversed-phase (RP) HPLC with electrochemical (coulometric) detection was used. The within-run and between-run coefficients of variations, for the two compounds, were less than 10%, in both platelets and plasma; the detection limits for platelet levels of L-dopa and 3-OMD were 2 and 6 ng/109 platelets, respectively. In plasma, the detection limits for L-dopa and 3- OMD were 1 and 3 ng/ml, respectively. The method is rapid and simple. When applied to a population of patients with Parkinson's disease under treatment with L-dopa, this method revealed detectable levels of L-dopa and 3-OMD in the platelets of all patients. The application of this technique may provide new insights into the pharmacokinetics of L-dopa in patients with Parkinson's disease.
|Number of pages||5|
|Journal||Journal of Chromatography B: Biomedical Applications|
|Publication status||Published - Oct 24 1997|
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