Isolation and structural characterization of colistin components.
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.
Orwa
J A
JA
Katholieke Universiteit Leuven, Faculteit Farmaceutische Wetenschappen, Belgium.
Govaerts
C
C
Busson
R
R
Roets
E
E
Van Schepdael
A
A
Hoogmartens
J
J
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
D000900:Anti-Bacterial Agents; D002247:Carbon Isotopes; D003091:Colistin