Journal of Chromatography B, 817 (2005) 303–307 Development and validation of a liquid chromatography and tandem mass spectrometry method for determination of roscovitine in plasma and urine samples utilizing on-line sample preparation Marina Vita a , Patrik Skansen b , Moustapha Hassan a , Mohamed Abdel-Rehim b,c,∗ a Department of Medicine, Division of Hematology, Laboratory of Hematology, Karolinska University Hospital, Huddinge, 141 86 Stockholm, Sweden b Department of Chemistry, Karlstad University, 651 58 Karlstad, Sweden c AstraZeneca R&DS¨ odert¨ alje, DMPK & BAC, SE-151 85 S¨ odert¨ alje, Sweden Received 15 November 2004; accepted 23 December 2004 Abstract Roscovitine, a purine analogue that selectively inhibits cyclin-dependent kinases, has been considered as a potential anti-tumor drug. The determination of roscovitine in plasma and urine was performed using microextraction in packed syringe as on-line sample preparation method with liquid chromatography and tandem mass spectrometry. The sampling sorbent utilized was polystyrene polymer. 2 H 3 -lidocaine was used as internal standard. The limit of detection for roscovitine was as low as 0.5 ng/mL and the lower limit of quantification was 1.0 ng/mL. The ac- curacy and precision values of quality control samples were between ±15% and ≤11%, respectively. The calibration curve was obtained within the concentration range 0.5–2000 ng/mL in both plasma and urine. The regression correlation coefficients for plasma and urine samples were ≥0.999 for all runs. The present method is miniaturized and fully automated and can be used for pharmacokinetic and pharmacodynamic studies. © 2005 Elsevier B.V. All rights reserved. Keywords: Roscovitine; Purine analogues; MEPS; 2 H 3 -lidocaine; LC–MS/MS 1. Introduction The measurement of drug levels in biological fluids is the corner stone for drug discovery and development as well as for pharmacodynamic and pharmacokinetic studies. Sample preparation is frequently done off-line and in fact, this is often a limiting step to perform fast bioanalysis; the intro- duction of on-line sample pretreatment would greatly speed up the analyses. Further, as the number of samples increases, high throughput and fully automated analytical techniques are required. Current developments of sample handling tech- niques are directed towards automatization and on-line cou- pling of sample preparation units and detection systems. In ∗ Corresponding author. Tel.: +46 8 55325604; mobile: +46 70 9569894; fax: +46 8 55329026. E-mail address: mohamed.abdel-rehim@astrazeneca.com (M. Abdel-Rehim). addition, there is a need for development of more selective sorbents for sample clean-up and enrichment [1–4]. Microex- traction in packed syringe (MEPS) is a new technique for miniaturized solid-phase extraction that can be connected on-line to gas chromatography (GC) or liquid chromatog- raphy (LC) without any modifications [1]. In MEPS, approx- imately 1 mg of the solid packing material is inserted into a syringe (100–250 L) as a plug [1]. The plasma sample (50–1000 L) is withdrawn through the syringe by an au- tosampler. When the plasma has passed through the solid support, the analytes are adsorbed to the solid phase. The solid phase is then washed once by water to remove the proteins and other interfering material. The analytes are then eluted with an organic solvent such as methanol or the LC mobile phase (20–50 L) directly into the instrument’s injector. The process is fully automated. Any adsorption material such sil- ica based (C2, C8, C18), restricted access material (RAM) or molecular imprinted polymers (MIPs) can be used. 1570-0232/$ – see front matter © 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.jchromb.2004.12.022