Novel polymyxin derivatives are less cytotoxic than polymyxin B to renal proximal tubular cells

► The tricationic NAB compounds were compared to the pentacationicpolymyxin B (PMB). ► To electroporated cells, the NAB compounds were 8-32 fold less toxic than PMB. ► Without electroporation, PMB was toxic at 0.5 mM while NABs were inert even at 1 mM. ► The toxicity manifested as necrosis, no apoptosis was observed.