High sensitive LC-MS/MS method for estimation of eluxadoline in human plasma and its application to pharmacokinetic...

A selective, sensitive and high throughput liquid chromatography - tandem mass spectrometry (LC-MS/MS) method was developed and validated for estimation of eluxadoline in human plasma. Plasma samples of analyte with internal standard (eluxadoline13CD3) were extracted using solid phase extraction on Orochem Panthera Deluxe cartridges. Chromatographic separation was performed on Ace Phenyl column (150 × 4.6 mm, 5 μm), using a mixture of buffer (2 mM ammonium acetate in 0.01% formic acid), acetonitrile and methanol (20:70:10, v/v/v) as mobile phase at a flow rate of 0.8 mL/min. The run time of analyte was 4.0 min. Tandem mass spectrometry, operating in positive ionization and multiple reaction monitoring modes was used for detection of analyte and internal standard. The method was established with a linear dynamic range of 25.0-5000 pg/mL for eluxadoline using 300 μL human plasma. The sample preparation procedure was consistent and reproducible (accuracy, 96.2-106.1%; precision (%CV), 0.8-6.6%), preventing the ex vivo hydrolysis of acyl glucuronide metabolite of eluxadoline to parent drug. The method was applied successfully to a clinical pharmacokinetic study in six healthy South Indian male subjects under fed conditions and the results were authenticated by incurred sample reanalysis.