Simultaneous Determination of Levodopa, Carbidopa, Entacapone, Tolcapone, 3- <i>O</i> -Methyldopa and Dopamine in Human Plasma by an Hplc–MS/MS Method

TLDR

The study developed and validated a HPLC–MS/MS method for simultaneous determination of levodopa, carbidopa, entacapone, tolcapone, 3‑O‑methyldopa, and dopamine in human plasma. Chromatographic separation was achieved on a C8 column using a gradient of water and acetonitrile:methanol (90:10 v/v) with 0.1 % formic acid, and the method was applied to plasma samples from Parkinson’s disease patients treated with Stalevo®. The method exhibited high selectivity, sensitivity (LOD < 7.0 ng mL⁻¹), linearity (r > 0.99), precision (RSD < 11.3 %), accuracy (RE < 11.8 %), and no residual or matrix effects, making it suitable for clinical monitoring and dosage adjustments.

Abstract

Background: In this study, we developed and validated a HPLC–MS/MS method capable of simultaneously determining levodopa, carbidopa, entacapone, tolcapone, 3-O-methyldopa and dopamine in human plasma. Results & methodology: Chromatographic separation was achieved using a C8 column with a mobile phase consisting of a gradient of water and acetonitrile:methanol (90:10 v/v), both containing 0.1% formic acid. The developed method was selective, sensitive (LD <7.0 ng ml-1), linear (r > 0.99), precise (RSD < 11.3%), accurate (RE < 11.8%) and free of residual and matrix effects. The developed method was successfully applied in plasma patients with Parkinson's disease using Stalevo®. Conclusion: The new method can be used for the clinical monitoring of these substances and applied to adjustments in drug dosages.