Research Article Received: 20 October 2008, Revised: 13 March 2009, Accepted: 6 April 2009 Published online in Wiley Interscience: 1 June 2009 (www.interscience.wiley.com) DOI 10.1002/bmc.1260 Copyright © 2009 John Wiley & Sons, Ltd. Biomed. Chromatogr. 2009; 23: 1350–1356 1350 John Wiley & Sons, Ltd. Rapid quantification of levosulpiride in human plasma using RP-HPLC-MS/MS for pharmacokinetic and bioequivalence study Rapid quantification of levosulpiride in human plasma Jin-Hee Park a , Yoo-Sin Park a , Si-Youn Rhim b , Hyun-Jin Kim a , Ok-Hwa Jhee c , Yun-Sik Lee d , Min-Ho Lee e , Leslie M. Shaw f and Ju-Seop Kang a * ABSTRACT: A rapid and validated method for analysis of levosulpiride in human plasma using liquid chromatography coupled to tandem mass spectrometry was developed. Levosulpiride and tiapride (IS, internal standard) were extracted from alkalized plasma samples with ethylacetate and separation by RP-HPLC. Detection was performed by positive ion electrospray ioniza- tion in multiple-reaction monitoring mode, monitoring the transitions m/z 342.1 → m/z 112.2 and m/z 329.1 → m/z 213.2, for quantification of levosulpiride and IS, respectively. The standard calibration curves showed good linearity within the range of 2–200 ng/mL (r 2 ≥ 0.9990). The lower limit of quantitation was 2 ng/mL. The retention times of levosulpiride (0.63 min) and IS (0.66 min) presented a significant time saving benefit of the proposed method. No significant metabolic compounds were found to interfere with the analysis. This method offered good precision and accuracy and was successfully applied for the pharmacokinetic and bioequivalence study of a 25 mg of levosulpiride tablet in 24 healthy Korean volunteers. Copyright © 2009 John Wiley & Sons, Ltd. Keywords: levosulpiride; LC-MS/MS; pharmacokinetics; bioequivalence study Introduction Levosulpiride, a purified levo-isomer of sulpiride, is a D 2 -dopamine receptor antagonist and commonly prescribed to patients with psychosis, depression and functional dyspepsia (Tonini et al., 2004; Hojo et al., 2005; Lozano et al., 2007). At low doses, levosulpiride increases dopaminergic neurotransmission, primarily by the blocking of the dopamine autoreceptors, which inhibits the pre-synaptic dopamine synthesis and release of dopamine even though in doses exceeding 600 mg daily it act as a selective antagosist at post-synaptic D 2 receptor. Compared with racemic- and dextro-forms, the levo-form of sulpiride has greater central antidopaminergic activity, antiemetic and antidyspeptic effects and lower acute toxicity (Mucci et al., 1995). Pharmacokinetics of levosupiride have been reported in healthy volunteers (Wiesel et al., 1980; Bressolle et al., 1992; Cho et al., 2004; Jin et al., 2004). Because of incomplete absorption from the gastrointestinal tract, estimated bioavailability of orally adminis- tered levosulpiride was demonstrated to be approximately 30% with marked interindividual differences. The pharmacokinetics of levosulpiride appeared to be linear at an oral dose ranging between 25 and 400 mg (Wiesel et al., 1980; Bressolle et al., 1992; Lee et al., 2003). For quantification of levosulpiride in human blood, a number of chromatographic methods have been developed. GC/MS techniques were reported early in the development of sulpiride and presented a low sensitivity of 50 ng/mL with time-consuming pre-column derivatization (Frigerio and Pantarotto, 1977). Several HPLC methods coupled with fluorescence detection (Tokunaga et al., 1997; Cho and Lee, 2003; Cho et al., 2004; Jin et al., 2004) and ultraviolet detection (UVD) (Bressolle and Bres, 1985; Koo et al., 2006) were developed. However, these methods possess disadvantages such as long analytical run times or back-extraction procedures for clear separation of levosulpiride, even though they presented sufficiently low lower limits of quantitation (LLOQs) of 0.25–10 ng/mL. Because the need to minimize the analytical time and to maximize the specificity and sensitivity is * Correspondence to: Ju-Seop Kang, Department of Pharmacology and Institute of Biomedical Sciences, College of Medicine; Department of Bioengineering, Hanyang University, Seoul 133-791, South Korea. E-mail: jskang@hanyang.ac.kr a Department of Pharmacology and Institute of Biomedical Sciences, College of Medicine; Department of Bioengineering, Hanyang University, Seoul 133-791, South Korea b Department of Surgery, College of Medicine, Hanyang University, Seoul 133- 791, South Korea c Department of Practical Arts Education, Gongju National University of Education, Gongju, South Korea d Department of Medical Zoology, College of Medicine, Kyunghee University, Seoul 130-701, South Korea e Department of Internal Medicine, College of Medicine, Hanyang University, Seoul, South Korea f Department of Pathology and Lab Medicine, College of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA Abbreviations used: HILIC, hydrophilic interaction liquid chromatography; MRM, multiple-reaction monitoring; UVD, ultraviolet detection. Contract/grant sponsor: Hanyang University; Contract/grant number: HY-2008C