The molecule is colistin A in which each of the primary amino groups is converted into the corresponding aminomethanesulfonic acid sodium salt, commonly by treatment with formaldehyde followed by sodium bisulfite. It is an organic sodium salt, a polymyxin and a peptide antibiotic. It contains a colistimethate A(5-). It derives from a colistin A.
pentasodium;[2-[(2S,5R,8S,11S,14S,17S,22S)-17-[(1R)-1-hydroxyethyl]-22-[[(2S)-2-[[(2S,3R)-3-hydroxy-2-[[(2S)-2-[[(6R)-6-methyloctanoyl]amino]-4-(sulfonatomethylamino)butanoyl]amino]butanoyl]amino]-4-(sulfonatomethylamino)butanoyl]amino]-5,8-bis(2-methylpropyl)-3,6,9,12,15,18,23-heptaoxo-11,14-bis[2-(sulfonatomethylamino)ethyl]-1,4,7,10,13,16,19-heptazacyclotricos-2-yl]ethylamino]methanesulfonate