Liquid chromatography/mass spectrometry for the quantitation of muraglitazar in monkey plasma

A high‐performance liquid chromatographic–mass spectrometric (LC/MS) assay was developed and validated for the determination of muraglitazar, a novel α / γ , dual PPAR activator, in monkey plasma. The method utilized trazodone as the internal standard (IS). The extraction scheme involved a simple protein precipitation procedure with the use of a mixture of acetonitrile and methylene chloride. Separation was carried out on a BDS Hypersil C 18 analytical column (2 × 50 mm, 3 µm) and an effective chromatographic separation of muraglitazar (3.31 min) and trazadone (2.27 min) was achieved at a ßow rate of 0.3 mL/min. The mobile phase, used in an isocratic mode, consisted of 90% A (acetonitrile: 0.1% formic acid, 50:50 v/v) and 10% B (acetonitrile: 0.1% formic acid, 95:5 v/v). Detection of muraglitazar and trazodone was by positive ion turbo‐ion spray mass spectrometry in the SIM mode. The mass spectrometer was programmed to admit the protonated molecules at m/z 372.0 (IS) and m/z 517.1 (muraglitazar). The standard curve, which ranged from 2 to 500 ng/mL, was fitted to a 1/ x weighted linear regression model. The between run precision and within‐run precision values of the assay was within 6.2% RSD. The assay accuracy was within 10.0% of the nominal values of the range of QC samples (6.0–400 ng/mL). At the lower limit of quantitation (LLQ) of 2 ng/mL, the deviation of the predicted concentrations from the nominal value of LLQ samples ( n = 6) were within ±16.6%. Muraglitazar was stable in monkey K 3 EDTA plasma for at least three freeze–thaw cycles. The processed samples (spiked samples) were stable for 48 h in auto‐sampler at 10°C. The average extraction recoveries of muraglitazar and IS were 83.3 and 91.9%, respectively. The assay was applied to delineate the pharmacokinetic disposition of muraglitazar in monkeys following a single oral dose. Copyright © 2006 John Wiley & Sons, Ltd.