Patent ID: 8357723

Claim:
A compound of formula (I) or pharmaceutically acceptable salts thereof: wherein, a is 0; B is S—S; A is CH 2 ; A 1 is CH 2 ; D 1 represents a therapeutic agent comprising one or more of the functional groups selected from the group consisting of —NHR 1 , —CONHR 1 , —SO 2 NHR 1 , —OSO 2 NHR 1 , N(R 1 )C(═O)NHR 1 and —N(R 1 )SO 2 NHR 1 ; wherein the N atom in said functional groups is either a part of or directly attached to L 1 ; D 2 represents a therapeutic agent comprising one or more of the functional groups selected from the group consisting of —OH, —SH, and —CO 2 H, wherein the O of —OH or the S of —SH or the C(═O) of the —C(═O)OH group is either a part of or directly attached to L 2 ; E is CH 2 ; L 1 represents NR 1 —(CO)—O and L 2 represents O—(CO)—; R 1 represents H or a bond to the residue of the therapeutic agent at an atom other than the atom to which N is attached.