Patent ID: 8329645

Claim:
A polymyxin derivative of formula: wherein A is a polymyxin ring moiety, wherein the polymyxin ring moiety has a formula of wherein R 1 ′ is the side chain of Abu; R 2 ′ is the side chain of Ala, Abu, Asn, Asp, Glu, Gln, Ser or Thr, each of which may be in the L or D configuration; R 3 ′ is the side chain of Ala, Abu, Asn, Asp, Glu, Gln, Ser or Thr, each of which may be in the L or D configuration; R4 is Glu, Asp, Dab, diaminopropionic acid, Thr, Ser or Cys; R5 is Dab or Abu; R6 is D-Phe or D-Leu; R7 is Leu, Thr or Ile; R8 is Dab or Abu; R9 is Dab or Abu; R10 is Thr or Leu; m 1 is 0 or 1; m 2 and m 3 are each 1; D is selected from R 12 —(C═O)—, R 12 —SO 2 —; R 12 —(C═NH)—; R 12 —NH—(C═S)—; R 12 —NH—(C═O)—; R 12 —NH—(C═NH)—; R 12 —O—(C═S)—; R 12 —O—(C═O)—; R 12 —P(O)OH—; R 12 —(C═S)—; or R 12 —, wherein R 12 is optionally substituted alkyl, alkenyl, alkynyl, aryl or aryl alkyl; wherein said polymyxin derivative has at least two but no more than three positive charges at physiological pH.