Fast quantitative determination of methylphenidate levels in rat plasma and brain ex vivo by MALDI-MS/MS.
This study presents a simple and sensitive high-throughput matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry (MALDI-MS/MS) method for ex vivo quantification of methylphenidate (MPH) in rat plasma and brain. The common MALDI matrix alpha-cyano-4-hydroxycinnamic acid was used to obtain an optimal dried droplet preparation. For method validation, standards diluted in plasma and brain homogenate prepared from untreated (control) rats were used. MPH was quantified within a concentration range of 0.1-40 ng/ml in plasma and 0.4-40 ng/ml in brain homogenate with an excellent linearity (R2≥ 0.9997) and good precision. The intra-day and inter-day accuracies fulfilled the FDA's ±15/20 critera. The recovery of MPH ranged from 93.8 to 98.5% and 87.2 to 99.8% in plasma and homogenate, respectively. We show that MPH is successfully quantified in plasma and brain homogenate of rats pre-treated with this drug using the internal standard calibration method. By means of this method, a linear correlation between plasma and brain concentration of MPH in rodents pre-treated with MPH was detected. The simple sample preparation based on liquid-liquid extraction and MALDI-MS/MS measurement requires approximately 10 s per sample, and this significantly reduces analysis time compared with other analytical methods. To the best of our knowledge, this is the first MALDI-MS/MS method for quantification of MPH in rat plasma and brain. Copyright © 2015 John Wiley & Sons, Ltd.
Cluster of Excellence 'Macromolecular Complexes', Department of Pharmaceutical Chemistry, School of Pharmacy, Goethe University, Frankfurt, Germany.
Anne
A
Arnold
Cluster of Excellence 'Macromolecular Complexes', Department of Pharmaceutical Chemistry, School of Pharmacy, Goethe University, Frankfurt, Germany.
Markus
M
Persike
Cluster of Excellence 'Macromolecular Complexes', Department of Pharmaceutical Chemistry, School of Pharmacy, Goethe University, Frankfurt, Germany.
Jan
J
Gorka
Brain and Behavioural Sciences, Department of Life, Health and Chemical Sciences, Biomedical Research Network, The Open University, Milton Keynes, UK.|Department of Psychology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.
Eleanor J
EJ
Dommett
Department of Pharmacology, School of Pharmacy, Goethe University, Frankfurt, Germany.
Martina
M
Zimmermann
Cluster of Excellence 'Macromolecular Complexes', Department of Pharmaceutical Chemistry, School of Pharmacy, Goethe University, Frankfurt, Germany.
Michael
M
Karas
MALDI MS/MS; methylphenidate; quantification; rat plasma and brain; small molecules