Abstract: Drug conjugates of formula [D-(X)b-(AA)w-(L)-]n-Ab wherein: D is a drug moiety having the following formula (I) or a pharmaceutically acceptable salt, ester, solvate, tautomer or stereoisomer thereof, wherein: A is selected from R1, R2 and R3 is H, ORa, OCORa, OCOORa, alkyl, alkenyl, alkynyl, etc; R3? is, CORa, COORa, CONRaRb, etc; each of R4 to R10 and R12 is alkyl, alkenyl or alkynyl; R11 is H, CORa, COORa, alkyl, alkenyl or alkynyl, or R11 and R12+N+C atoms to which they are attached may form a heterocyclic group; each of R13 and R14 is H, CORa, COORa, alkyl, alkenyl or alkynyl; each Ra and Rb is H, alkyl, alkenyl, alkynyl, etc.