Journal of Chromatography B, 857 (2007) 219–223 Estimation of carvedilol in human plasma by using HPLC-fluorescence detector and its application to pharmacokinetic study Rajeshwari Rathod, L. Poorna Chandra Prasad, Shubha Rani, Manish Nivsarkar, Harish Padh ∗ B.V. Patel Pharmaceutical Education and Research Development (PERD) Centre, Thaltej-Ghandhinagar Highway, Thaltej, Ahmedabad 380 054, India Received 20 February 2006; accepted 13 July 2007 Available online 22 July 2007 Abstract A simple, precise and sensitive high performance liquid chromatography procedure has been developed for determination of carvedilol in human plasma. The method was developed on Lichrosphere R CN column using a mobile phase of acetonitrile/20 mM ammonium acetate buffer with 0.1% triethylamine (pH adjusted to 4.5) (40/60, v/v). The peaks were detected by using fluorescence detector (excita- tion wavelength 282 nm and emission wavelength 340 nm). Carvedilol and domperidone (internal standard) were extracted by liquid–liquid extraction procedure using dichloromethane. This method was specific and had a linearity range of 1–128 ng/ml with intra- and inter- day precision (%C.V.) less than 15%. The accuracy ranges from 87.3 to 100.88% and the recovery of carvedilol was 69.90%. The stability studies showed that carvedilol in human plasma was stable during short-term period for sample preparation and analysis. This method was used to assay the carvedilol in human plasma samples obtained from subjects who had been given an oral tablet of 12.5 mg carvedilol. © 2007 Elsevier B.V. All rights reserved. Keywords: Carvedilol; HPLC-fluorescence detector; Liquid–liquid extraction; Pharmacokinetics 1. Introduction Carvedilol (Fig. 1a) is a -blocker with additional vasodi- lating, anti-proliferative and antioxidative properties [1]. Chemically it is 1-(9H-carbazol-4-yloxy)-3-[[2-(2-methoxy phenoxy) ethyl] amino]-2-propanol [2]. Several methods have been reported for estimation of carvedilol in human plasma using HPLC with fluorescence detector [3], electrochemical detector [4], LC–MS and capillary electrophoresis [5–7]. The limit of quantification (LOQ) has been reported as 1.30 ng/ml for HPLC- fluorescence detector and in LC–MS the report [5] shows LOQ up to 0.1 ng/ml. In some reported methods, solid phase extrac- tion was used for extraction process [8]. However, the solid phase extraction and LC–MS methods are very costly. In this ∗ Corresponding author. Tel.: +91 79 27439375/27416409; fax: +91 79 27450449. E-mail address: perd@perdcentre.com (H. Padh). URL: http://www.perdcentre.com (H. Padh). paper we report a simple, accurate and highly specific method for estimation of carvedilol in human plasma by using HPLC with fluorescence detector. This method has the advantage of using simple liquid–liquid extraction with good recovery and having LOQ of 1 ng/ml. 2. Experimental 2.1. Materials and chemicals Carvedilol was a gift sample (Troikaa Pharmaceuticals Ltd., Ahmedabad, Gujarat, India). Domperidone (Fig. 1b) was used as an internal standard (Torrent Pharmaceuticals Ltd., Ahmed- abad, Gujarat, India). All the solvents were of HPLC grade from Qualigen Fine Chemicals and Spectrochem, India. Ammonium acetate (S.D. Fine Chem. Ltd., Mumbai, Maharashtra, India) and acetic acid (S.D. Fine Chem. Ltd., Mumbai, Maharashtra, India) of analytical grade were used. Human plasma was obtained from Prathma blood bank, Ahmedabad, Gujarat, India. 1570-0232/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.jchromb.2007.07.021