Journal of Chromatography A, 1097 (2005) 74–83 Solid-phase extraction coupled with liquid chromatography–tandem mass spectrometry for determination of trace rosiglitazone in urine Chi-Chi Chou a , Maw-Rong Lee a,∗ , Fu-Chou Cheng b , Dar-Yu Yang c a Department of Chemistry, National Chung-Hsing University, 250 Kuo-Kuang Road, Taichung 40227, Taiwan b Department of Medical Research, Taichung Veterans General Hospital, Taichung 40705, Taiwan c Department of Emergency, Taichung Veterans General Hospital, Taichung 40705, Taiwan Received 2 April 2005; received in revised form 25 July 2005; accepted 5 August 2005 Available online 6 September 2005 Abstract This project evaluated solid-phase extraction (SPE) combined with liquid chromatography–tandem mass spectrometry (LC–MS/MS) to determine the trace amount of rosiglitazone in human urine. The analytical performance of four modes of LC–MS and tandem MS operation (atmospheric pressure chemical ionization (APCI), electrospray ionization (ESI), positive and negative ionization) was compared for two mass spectrometers, a triple-quadrupole and a quadrupole ion trap instrument. Rosiglitazone was extracted from urine using a SPE cartridge of 50 mg C8 sorbent and acetonitrile used as the eluting solvent. Samples were then separated on a RP18 column interfaced with a tandem mass spectrometer. The recovery of rosiglitazone was greater than 91.2%. The urine assay combining SPE and LC–APCI-MS/MS of triple-quadrupole was proved a very selective and sensitive method for determination of trace rosiglitazone. The assay was linear over a wide range, with a lower limit of quantification of 0.1 ng/mL using 1mL of urine. The intra- and inter-day precisions were <9.8% and <7.9%, respectively, and the accuracies were in the range 91.0–103.6%. The rosiglitazone concentration profile in human urine was also determined. The results of this study reveal the adequacy of SPE–LC–APCI- MS/MS method for analyzing rosiglitazone from diabetic patients’ urines. The concentrations of rosiglitazone were detected to range from 760 to 164 pg/mL. © 2005 Elsevier B.V. All rights reserved. Keywords: Rosiglitazone; Urine; Solid-phase extraction; Liquid chromatography; Tandem mass spectrometry 1. Introduction Rosiglitazone, [(±)-5-[[4-[2-methyl-2-(pyridinylamino)eth- oxy]phenyl]methyl]-2,4-thiazoli-dinedione-(Z)-2-butenedioate (1:1)] (Fig. 1A) is a potent synthetic peroxisome proliferators- activated receptor gamma (PPAR-) agonist that decreases hyperglycemia by reducing insulin resistance in patients with type 2 (noninsulin-dependent) diabetes as both monother- apy and in combination with oral antidiabetic agents [1,2]. Rosiglitazone is in a class of drugs called thiazolidinediones which work by increasing insulin sensitivity in target tissues, as well as decreasing hepatic gluconeogenesis [3,4]. Some concern about class safety has been raised by the removal of troglitazone from the market due to human hepatotoxicity and severe, irreversible liver failure [5]. Although rosiglitazone ∗ Corresponding author. Tel.: +886 4 2285 1716; fax: +886 4 2286 2547. E-mail address: mrlee@mail.nchu.edu.tw (M.-R. Lee). does not seem to share this problem, the mechanisms of troglitazone reactions are not clearly elucidated. However, there is a substantial amount of evidence that chemically reactive metabolites are involved for the liver toxicity [6]; the knowledge about metabolic steps is a prerequisite for toxicological risk assessment. As a result, methods for rapidly detecting and characterizing rosiglitazone and its metabolites are highly desired in this class of drugs. Rosiglitazone was derived from a metabolite of ciglitazone and found to be much more potent than other classes of thiazolidinediones such as pioglitazone, ciglitazone and englitazone [7]. This drug contains a thiazolidinedione core, but differs from other thiazolidinediones in the presence of an aminopyridyl side chain [8]. Such substitutions among side chains are believed to be responsible for differences in disposition, antidiabetic efficacy and metabolism among thiazolidinediones [9]. Rosiglitazone is primarily eliminated via metabolism in the liver by cytochrome P450 isoenzyme 2C8. Following oral treatment rosiglitazone is rapidly absorbed (T max 1–2 h) with 0021-9673/$ – see front matter © 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.chroma.2005.08.033