A high-performance liquid chromatography-tandem mass spectrometry method for quantification of perampanel in human plasma: Effect of concomitant anti-seizure medications on perampanel concentration in patients with epilepsy.

Perampanel is a first-in-class α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor antagonist and a novel anti-seizure medication. It is currently used as adjunctive treatment for partial seizures in patients over 12 years of age. With the increasing clinical application of perampanel, monitoring its concentration under certain clinical conditions is important. This study developed a rapid and sensitive high-performance liquid chromatography-tandem mass spectrometry method to quantify perampanel in human plasma. Protein precipitation with acetonitrile was performed for sample preparation. Perampanel and perampanel-d5 (internal standard) were analyzed under gradient conditions using a C18 column. The mobile phase was composed of 0.1% (v/v) formic acid in water (solvent A) and 0.1% (v/v) formic acid in acetonitrile (solvent B) at a flow rate of 0.4 mL/min. Mass detection was performed using multiple reaction monitoring in the positive ionization mode. The proposed method was validated over a range of 0.5-500 ng/mL for perampanel. The linearity (r value) was higher than 0.999, and the linear equation was y = 0.00116x + 0.0116. The accuracy of the low-, middle-, and high-quality control samples was between 103% and 113%, and the intra- and inter-day precisions were below 6.81%. The quality of the proposed method was evaluated in accordance with the US Food and Drug Administration Bioanalytical Method Validation Guidance for Industry. The plasma concentrations of perampanel in 25 patients were successfully determined to be 38.7-577.7 ng/mL using the validated method.