SPR206 acetate is a polymyxin analog with antibiotic activity against Gram-negative pathogens, including multidrug-resistant (MDR) variants. SPR206 acetate has an anti-bacterial infection effect by interacting with the bacterium’s outer membrane. The MIC values of SPR206 acetate against Pseudomonas aeruginosa Pa14 and Acinetobacter baumannii NCTC13301 are both 0.125 mg/L[2].IC50 & Target:MIC: 0.125 mg/L (Pseudomonas aeruginosa Pa14) and 0.125 mg/L (Acinetobacter baumannii NCTC13301)[2]In Vitro: SPR206 exhibits strong anti-microbial properties against Gram-negative bacteria. The MIC values of SPR206 against E. coli IHMA558090, E. coli ATCC 25922, K. pneumonia ATCC 13882, P. aeruginosa ATCC 27853, A. baumannii NCTC13424 and A. baumannii ATCC 19003 are 8 mg/L, 0.125 mg/L, 0.125 mg/L, 0.25 mg/L, 0.06 mg/L and 0.125 mg/L, respectively, together with lower cytotoxicity .In Vivo: SPR206 (0.125-30 mg/kg; intravenous injection or subcutaneous injection; every 8 hours or every 4 hours; for 16 hours or 24 hours; neutropenic mice) treatment reduces the burden of Pa14 and NCTC13301 in lung tissue and in the thigh model[2].