Journal of Pharmaceutical and Biomedical Analysis 54 (2011) 694–700 Contents lists available at ScienceDirect Journal of Pharmaceutical and Biomedical Analysis journal homepage: www.elsevier.com/locate/jpba Optimisation and validation of a fast HPLC method for the quantification of sulindac and its related impurities Fabrice Krier a,∗ , Michaël Brion a , Benjamin Debrus b , Pierre Lebrun b , Aurélie Driesen a , Eric Ziemons b , Brigitte Evrard a , Philippe Hubert b a Laboratory of Pharmaceutical Technology, Department of Pharmacy, CIRM, University of Liège, Av. de l’Hôpital 1, 4000 Liège, Belgium b Laboratory of Analytical Chemistry, Department of Pharmacy, CIRM, University of Liège, Av. de l’Hôpital 1, 4000 Liège, Belgium article info Article history: Received 23 July 2010 Received in revised form 19 October 2010 Accepted 27 October 2010 Available online 3 November 2010 Keywords: HPLC Sulindac Validation Design space Sub-2micron column abstract The European Pharmacopoeia describes a liquid chromatography (LC) method for the quantification of sulindac, using a quaternary mobile phase including chloroform and with a rather long run time. In the present study, a new method using a short sub-2 m column, which can be used on a classical HPLC system, was developed. The new LC conditions (without chloroform) were optimised by means of a new methodology based on design of experiments in order to obtain an optimal separation. Four factors were studied: the duration of the initial isocratic step, the percentage of organic modifier at the beginning of the gradient, the percentage of organic modifier at the end of the gradient and the gradient time. The optimal condition allows the separation of sulindac and of its 3 related impurities in 6 min instead of 18 min. Finally, the method was successfully validated using an accuracy profile approach in order to demonstrate its ability to accurately quantify these compounds. © 2010 Elsevier B.V. All rights reserved. 1. Introduction Sulindac is a non-steroidal anti-inflammatory drug with a poor pharmacological activity. It can be metabolised by reversible reduc- tion into a sulphide metabolite, with a high pharmacological activity, or by irreversible oxidation into a sulphone metabolite, which has no pharmacological activity [1]. E-sulindac is an impu- rity resulting from the synthesis of sulindac. Sulindac is used for the treatment of acute or chronic inflammatory conditions. High- performance liquid chromatography (HPLC) is the most commonly used technique for the analysis of sulindac and its related impurities [2–6]. The European Pharmacopoeia (Eur. Ph.) [7] describes a nor- mal phase HPLC method for this purpose. However, this method requires a quaternary mobile phase containing chloroform and a rather long analysis time. In pharmaceutical, biomedical and food analysis, the recent trend has been to develop fast analysis methods (fast-HPLC) [8–11]. ∗ Corresponding author at: Laboratory of Pharmaceutical Technology, Depart- ment of Pharmacy, CIRM, University of Liège, Av. de l’Hôpital 1, Bât. B36, CHU, Tour 4, 4000 Liège, Belgium. Tel.: +32 4 3664306; fax: +32 4 3664302. E-mail address: Fabrice.Krier@ulg.ac.be (F. Krier). Over the last decade, different strategies have been developed to reduce the analysis time while maintaining efficiency or to improve efficiency with a similar analysis time [12,13]. One of these strategies, ultra-performance liquid chromatography (UHPLC) uses a column packed with sub-2 m particles. However, such small particles generate high back pressure and necessitate the use of appropriate and quite expensive equipment able to withstand such an ultra high pressure (up to 1200 bar). In order to reduce back pressure, some column manufacturers put forward the use of short sub-2 m columns with a higher internal diameter. The advantage of this type of column is that it can be used with conventional HPLC equipment (up to 400 bar) [14]. In this study, a Platinum C18 Rocket column (53 × 7 mm i.d., 1.5 m particle size) was used. This column provides a shorter analysis time, a lower solvent, faster equilibra- tion, accurate quantitation and high efficiency [15,16]. Some recent papers report methods based on this brand of column for the deter- mination of pharmaceutical substances in plant tissues [17–19], for the monitoring of amiodarone [20], or for the separation of micro- cystins and nodularins on narrow-bore [21]. In this study, a new fast and easy HPLC method was developed without the use of chlo- roform for the separation and determination of sulindac and its related impurities. This method was optimised in terms of separa- tion by using design of experiments (DoE) methodology [22–24] and the design space (DS) concept [25,26]. Finally, the method was validated using the accuracy profile approach based on a ˇ- expectation tolerance interval [27–32]. 0731-7085/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.jpba.2010.10.022