N. LindegårdhF. GiorgiB. GallettiM. Di MattiaM. QuagliaD. CarnevaleN. J. WhiteA. MazzantiN. P.J. DayMahidol UniversityNuffield Department of Clinical MedicineSigma-Tau S.p.A.Alma Mater Studiorum Universita di Bologna2018-08-202018-08-202006-12-01Journal of Chromatography A. Vol.1135, No.2 (2006), 166-169002196732-s2.0-33750611489https://repository.li.mahidol.ac.th/handle/20.500.14594/22942A significant contaminant of the antimalarial drug piperaquine (1,3-bis-[4-(7-chloroquinolyl-4)-piperazinyl-1]propane) has been identified using liquid chromatography-mass spectrometry (LC-MS) and 2D NMR spectroscopy (1H-1H COSY,1H-13C HSQC,1H-13C HMBC). The impurity was identified as the positional isomer 1-[(5-chloroquinolin-4)-piperazinyl]-3-[(7-chloroquinolin-4)-piperazinyl]propane. The impurity is formed because of contamination of batches of 4,7-dichloroquinoline (a precursor in the synthesis of piperaquine) with 4,5-dichloroquinoline. The amount of impurity (peak area impurity/peak area piperaquine using LC-UV at 347 nm) in old batches of piperaquine and in Artekin (the combination of dihydroartemisinin-piperaquine) ranged from 1.5 to 5%. © 2006 Elsevier B.V. All rights reserved.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyChemistryArticleSCOPUS10.1016/j.chroma.2006.09.066