85419-94-9 Peg-SS Poly(oxy-1,2-ethanediyl), alpha-(4-((2,5-dioxo-1-pyrrolidinyl)oxy)-1,4-dioxobutyl)-omega-(4-((2,5-dioxo-1-pyrrolidinyl)oxy)-1,4-dioxobutoxy)- Polyethylene glycol bis(succinimidyl succinate)