LC-MS-MS Simultaneous Determination of l-Dopa and Its Prodrug l-Dopa n-Pentyl Ester Hydrochloride in Rat Plasma

A sensitive, simple and rapid LC-MS-MS method has been developed and validated for the simultaneous determination of l-dopa and l-dopa n-pentyl ester hydrochloride in rat plasma in the present study. The analytes were separated on a C₁₈ column (5 μm, 2.1 × 150 mm) with a security guard C₁₈ column (5 μm, 4 × 20 mm) and a triple-quadrupole mass spectrometer was applied for detection. The method was linear over the concentration ranges of 25-5,000 ng mL⁻¹ for l-dopa and 12.5-2,500 ng mL⁻¹ for l-dopa n-pentyl ester hydrochloride. Finally, the method was successfully applied to support the pharmacokinetic study.