Synonyms: PolymyxinB1, 10-L-leucine-; 1,4,7,10,13,16,19-Heptaazacyclotricosane, cyclic peptidederiv.; L-Leucine, N2-(6-methyl-1-oxooctyl)-L-2,4-diaminobutanoyl-L-threonyl-L-2,4-diaminobutanoyl-L-2,4-diaminobutanoyl-L-2,4-diaminobutanoyl-D-phenylalanyl-L-leucyl-L-2,4-diaminobutanoyl-L-2,4-diaminobutanoyl-,cyclic (10®4)-peptide