Patent ID: 8613930

Claim:
A cell-binding agent-drug conjugate of formula (II) wherein: CB represents a cell-binding agent; D represents a cytotoxic drug linked to the cell-binding agent by a disulfide, thioether, thioester, peptide, hydrazone, ester, ether, carbamate, or amide bond; R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , and R 10 are the same or different and are H, linear alkyl having from 1-6 carbon atoms, branched or cyclic alkyl having from 3 to 6 carbon atoms, linear, branched or cyclic alkenyl or alkynyl having from 2 to 6 carbon atoms, a charged substituent selected from anions selected from SO 3 − , X—SO 3 − , OPO 3 2− , X—OPO 3 2− , PO 3 2− , X—PO 3 2− , and cations selected from a nitrogen containing heterocycle, N + R 11 R 12 R 13 and X—N + R 11 R 12 R 13 , or a phenyl; wherein: R 11 , R 12 , and R 13 are the same or different and are linear alkyl having from 1 to 6 carbon atoms, branched or cyclic alkyl having from 3 to 6 carbon atoms and X represents phenyl or a linear alkyl from 1 to 6 carbon atoms, or branched or cyclic alkyl having from 3 to 6 carbon atoms; l, m and n are 0 or an integer from 1 to 4; Z is an optional polyethyleneoxy unit of formula (OCH 2 CH 2 ) p , wherein p is 0 or an integer from 2 to about 1000; Y represents a carbonyl, thioether, amide, disulfide, or hydrazone group; and q represents an integer from 1 to 20; wherein at least one of R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , and R 10 is a charged substituent.