A Sensitive and Selective GC–MS Method for Analysis of Process-Related Genotoxic Impurities in Atenolol Yogeshwar Reddy Mamilla 1,3,& , Kista Reddy Chetyala 3 , Ramesh Venna 2 , Raju Gajjela 2 , Kishore Katragadda 1 , Saravanan Govindasamy 1 , Suryanarayana Mulukutla 1 , Debashish Datta 1 1 R&D Centre, Matrix Laboratories Ltd, Jinnaram, Medak 502325, India; E-Mail: yogeshwar.mamilla@matrixlabsindia.com 2 National Centre for Mass Spectrometry, Indian Institute of Chemical Technology, Hyderabad, India 3 Department of Chemistry, P.G. College of Science, Saifabad, Hyderabad, India Received: 28 September 2009 / Revised: 4 January 2010 / Accepted: 20 January 2010 Online publication: 24 April 2010 Abstract A sensitive GC–MS method for analysis of residues of allyl chloride (2), 1,3-dichloro-2- propanol (3), and 2,3-dichloro-1-propanol (4), genotoxic impurities in atenolol (1) drug substance, has been developed and validated. Under the optimum conditions used for sample preparation, recovery of 2, 3, and 4 from samples spiked at three concentrations, in triplicate, was from 97.1 to 99.3%, from 97.6 to 104.7%, and from 90.1 to 96.8%, respectively. Limits of quantification and detection were 0.003 and 0.001 mg g -1 , respec- tively, for standard solutions of the compounds. Response was a linear function of concen- tration in the range 0.003–0.018 mg g -1 with correlation coefficients 0.9910, 0.9964, and 0.9960 for 2, 3, and 4, respectively. Keywords Gas chromatography–mass spectrometry Atenolol Selected-ion monitoring Introduction Atenolol ((RS)-2-{4-[2-hydroxy-3-(pro- pan-2-ylamino)propoxy]phenyl}acetam- ide) is used for treatment of cardiovascular diseases and conditions such as hypertension, coronary heart disease, arrhythmias, and angina (chest pain), and to treat and reduce the risk of heart complications after myocardial infarction (heart attack) and angina [1]. In the synthesis of atenolol (1), ally chloride (2), 1,3-dichloro-2-propanol (3), and 2,3-dichloro-1-propanol (4) are important reagents. The chemical struc- tures of compounds 1–4 are given in Fig. 1. Identification and quantification of compounds 2–4 as impurities in 1 are essential, because of their genotoxic nature [2]. Regulatory guidelines [3] stipulate a threshold of toxicological concern (TTC) value of 1.5 lg day -1 for intake of a toxic impurity. The permit- ted quantity in ppm is the ratio of the TTC in micrograms per day to the dose in grams per day. Because 200 mg atenolol is administered per day [4] in the form of tablets (25–200 mg; trade name Tenormin); the estimated per- missible quantity of these impurities is 7.5 ppm per day. Several GC–MS studies have been conducted on atenolol and other b-block- ers [5–8]. Forsdahl et al. [5] reported a method for sensitive detection of isopropyl- substituted b-blocking agents in human urine. Their sample-preparation step in- volved enzymatic hydrolysis, solid-phase extraction, and derivatization with N-me- thyl-N-trimethylsilyltrifluoroacetamide; Electronic supplementary material The online version of this article (doi:10.1365/ s10337-010-1503-3) contains supplementary material, which is available to authorized users. 2010, 71, 733–736 DOI: 10.1365/s10337-010-1503-3 0009-5893/10/04 Ó 2010 Vieweg+Teubner | GWV Fachverlage GmbH Limited Short Communication Chromatographia 2010, 71, April (No. 7/8) 733