Journal of Chromatographic Science, 2018, Vol. 56, No. 9, 846–852 doi: 10.1093/chromsci/bmy062 Advance Access Publication Date: 30 June 2018 Article Article Reversed-Phase High-Performance Liquid Chromatography and High-Performance Thin- layer Liquid Chromatography Methods for Simultaneous Determination of Theophylline, Guaifenesin and Guaifenesin Impurity (Guaiacol) in Their Bulk Powders and in Dosage Form Eglal A. Abdelaleem 1 , Ibrahim A. Naguib 1 , Shimaa A. Farag 2, * , and Hala E. Zaazaa 3 1 Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Beni-Suef University, 62111 Beni-Suef, Egypt, 2 Analytical Chemistry Department, Faculty of Pharmacy, Nahda University, Beni-Suef 62111, Egypt, and 3 Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Cairo University, Kasr El-Aini St., 11562 Cairo, Egypt * Author to whom correspondence should be addressed. Email: shosho_5005eg@yahoo.com Received 6 August 2016; Revised 16 May 2018; Editorial Decision 1 June 2018 Abstract Two simple, rapid chromatographic methods were developed for the simultaneous determination of Theophylline (THP), Guaifenesin (GUI) and Guaifenesin impurity namely Guaiacol (GUA). The first method is an isocratic reversed-phase high-performance liquid chromatography (RP-HPLC) method, where separation of THP, GUI and GUA was achieved on C 18 column using methanol: water (containing 0.1% triethylamine):acetonitrile (30:60:10, by volume) as a mobile phase with a flow rate of 0.7 mL /min and UV detection at 275 nm. The separation was achieved at retention times (R t 3.76, 6.76 and 8.79 for THP, GUI and GUA, respectively). The calibration plots were linear over the concentration range of 2–25, 2–37 and 0.5–10 μg /mL for THP, GUI and GUA, respectively. The second method is high pressure thin layer liquid chromatography method, which was devel- oped using silica gel plates 60F 254 as a stationary phase with ethyl acetate:hexane:methanol: ammonia (65:35:10:2, by volume) as a developing system. The densitometric measurements were performed at 275 nm with good R f values (0.13, 0.35 and 0.8) for THP, GUI and GUA, respectively. The calibration plots showed good correlation over the range (0.4–2 μg/band) for both THP and GUI, and (0.4–1.2 μg/band) for GUA. The two proposed methods were validated according to ICH guidelines. The results for the two methods were statistically compared to those obtained by a re- ported high-performance liquid chromatography method and no significant difference was found regarding accuracy and precision. Introduction Theophylline (THP) is 1,3-dimethyl-7H-purine-2,6-dione (1) (Figure 1a); a member of xanthine-based alkaloids, which relaxes smooth muscles, relieves broncospasm and has a stimulant effect on respira- tion (2). Guaifenesin (GUI) is (RS)-3-(2-methoxyphenoxy) propane- 1, 2-diol (1) (Figure 1b); it is reported to increase the volume and © The Author(s) 2018. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com 846 Downloaded from https://academic.oup.com/chromsci/article/56/9/846/5047156 by guest on 12 July 2021