CAS 207990-63-4 appears in our catalog under these names: Polymyxin E1 sulfate, Polymyxin E1 (sulfate), Colistin A sulfate, Colistin A sulfate, Concentration: 100 µg/ml Solvent: Acetonitrile/Water 50/50. Offered by: TargetMol, GLPBio, HPC Standards. Available pack sizes: 1mg, 500ug, 500μg, 1x5mg, 1x1ml.