Validated UHPLC–MS/MS method for the simultaneous determination of pramipexole and ropinirole in plasma of patients with Parkinson’s disease

• Plasma analysis of pramipexole and ropinirole is grouped in an only validated assay.
• The assay is based on UHPLC–MS/MS with liquid–liquid extraction on 250 μL plasma.
• The same assay allows to process large series of patient samples in a single session.

A simple and validated ultra high pressure liquid chromatography–tandem mass spectrometry method was developed for the simultaneous determination of the dopaminergic agents pramipexole and ropinirole in plasma of patients with Parkinson’s disease. Following liquid–liquid extraction with tert-butyl methyl ether from 250 μL plasma, the separation of the analytes was achieved on a Gemini NX3 column using 10 mM pH 6.0 ammonium formate and 10 mM ammonium formate in methanol as binary gradient mobile phase at a flow rate of 0.3 mL/min. The MS/MS ion transitions were 212.10 → 153.03 for pramipexole, 261.2 → 114.2 for ropinirole and 256.1 → 211 for the internal standard (lamotrigine). The lower limit of quantitation (LLOQ) for both analytes was 80 pg/mL and the linearity was determined from 80 to 4000 pg/mL for pramipexole and from 200 to 10000 pg/mL for ropinirole. Mean recoveries were 94% for PRA and 73% for ROP. Both intra- and inter-assay precision and accuracy were ≤20% at LLOQ concentration and ≤15% at other concentrations. The proposed validated method was successfully applied to measure plasma concentrations of pramipexole and ropinirole in a series of patients with Parkinson’s disease on chronic treatment. By grouping the two dopaminergic agents in the same assay, the method allows a large series of patient samples to be processed in a single analytical session.