Patent ID: 6716821
Filing Date: 2004-04-06
Classification: A61K,A61P

Abstract:
A cytotoxic agent, bearing a polyethylene glycol (PEG) linking group having a terminal active ester and 1 to 20 monomeric units, of formula 2: wherein:Z-S is a thiol-containing cytotoxic agent; Q is R2COOâ€”, R2R3NCOOâ€”, R2OCOOâ€”, R2Oâ€”, R2CONR3â€”, R2R3Nâ€”, R2OCONR3â€”, or Sâ€”, â€ƒwherein: R2 is SCR4R5R6â€”, wherein R4, R5 and R6 are each H, linear alkyl, cyclic alkyl or branched alkyl, and may be the same or different; R3 is H or a linear alkyl, cyclic alkyl or branched alkyl; n is an integer of from 0 to 20; x is 1 or 2; and Y is N-succinimidyl, N-sulfosuccinimidyl, N-phthalimidyl, N-sulfophthalimidyl, 2-nitrophenyl, 4-nitrophenyl, 2,4-dinitrophenyl, 3-sulfonyl-4-nitrophenyl or 3-carboxy-4-nitrophenyl.