title: Isolation and structural characterization of colistin components.
abstract: Preparative-scale separation of colistin sulphate bulk sample was carried out on a preparative poly(styrene-divinylbenzene) stationary phase. Isocratic elution with acetonitrile-sodium sulphate solution (0.7% m/v; pH adjusted to 2.5 with TFA) - water (16:50:34, % v/v/v) was carried out at a flow rate of 4.0 ml min(-1). Six colistin components were isolated and characterized using 1H and 13C NMR. The molecular weights were confirmed by mass spectrometry. The structures of 2 components were determined for the first time. Polymyxin E7 was identified as having the same composition as polymyxin E1, except that the fatty acid moiety was 7-methyloctanoic acid. Isoleucine polymyxin E8 was characterized as having the same composition as isoleucine polymyxin E1 with 7-methylnonanoic acid as the fatty acid moiety.
authors.affiliation: Katholieke Universiteit Leuven, Faculteit Farmaceutische Wetenschappen, Belgium.
authors.forename: J A
authors.initials: JA
authors.lastname: Orwa
authors.forename: C
authors.initials: C
authors.lastname: Govaerts
authors.forename: R
authors.initials: R
authors.lastname: Busson
authors.forename: E
authors.initials: E
authors.lastname: Roets
authors.forename: A
authors.initials: A
authors.lastname: Van Schepdael
authors.forename: J
authors.initials: J
authors.lastname: Hoogmartens
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000302:isolation & purification; D002247:Carbon Isotopes; D002851:Chromatography, High Pressure Liquid; D003091:Colistin / Q000737:chemistry* / Q000302:isolation & purification; D009682:Magnetic Resonance Spectroscopy
chemical_list: D000900:Anti-Bacterial Agents; D002247:Carbon Isotopes; D003091:Colistin