Liquid Chromatography-Tandem Mass Spectrometry for the Determination of Methylprednisolone in Rat Plasma and Liver After Intravenous Administration of Its Liver-Targeted Dextran Prodrug

A specific and sensitive liquid chromatography (LC)-tandem mass spectrometric method for quantitative determination of methylprednisolone (MP) in rat plasma and liver was developed and validated using triamcinolone acetonide as an internal standard. Liquid-liquid extraction using tert-butyl methyl ether was used to extract the drug and the internal standard from plasma and liver. The separation of MP was performed on a C(18) column with a mobile phase of acetonitrile:0.5% formic acid aqueous solution (85:15, v/v) over 4 min. The assay was based on the selected reaction monitoring transitions at m/z 375 -\u3e 161 for MP in plasma, 375 -\u3e 357 for MP in liver, and 435 -\u3e 415 for internal standard in both plasma and liver. The lower limit of quantification was 20 ng/mL based on 100 mu L of plasma or liver homogenate. Intra- and inter-clay assay variations wer