title: Isolation and structure characterization of related impurities in etimicin sulfate by LC/ESI-MS(n) and NMR.
abstract: Etimicin sulfate is a semi-synthetic aminoglycoside which is modified from gentamicin C1a, used as an antibiotic effective both to Gram-positive and Gram-negative bacteria infections. Ten impurities were detected in the bulk drug by LC-ELSD and LC-ESI-MS(n). Weakly acidic cation exchange resin, CM-sephadex and silica gel column chromatography were used for the isolation of six impurities. Based on LC/ESI-MS(n) and NMR analysis, related impurities were characterized as gentamicin C1a (1), 1-N-ethyl garamine (2), 2″-N-ethyl gentamicin C1a, or 6″-N-ethyl gentamicin C1a (3), 1-N-ethyl-3'-N-demethyl gentamicin C2b (4), 3-N-ethyl gentamicin C1a (5), 6″-deamino-6″-hydroxyl etimicin (6), 1,3-N, N-diethyl garamine (7), 1-N-ethyl gentamicin C2b (8), 2″ or 6″-N-ethyl etimicin (9), 1,3-N, N-diethyl gentamicin C1a (10). 10 is a new aminoglycoside, the (1)H and (13)C NMR data of compounds 5-7, 10 are first reported in the paper. The possible mechanism for the formation of impurities is also discussed.
authors: Key Laboratory of Modern Chinese Medicines, China. btwanghao@yahoo.com.cn
authors: Hao
authors: H
authors: Wang
authors: Zhijie
authors: Z
authors: Zhang
authors: Fei
authors: F
authors: Xiong
authors: Lingyun
authors: L
authors: Wu
authors: Ping
authors: P
authors: Li
authors: Wencai
authors: W
authors: Ye
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000379:methods; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D002853:Chromatography, Liquid / Q000379:methods*; D005839:Gentamicins / Q000032:analysis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008956:Models, Chemical; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D005839:Gentamicins; C555708:etimicin sulfate