Patent ID: 8217005

Claim:
A compound of structural Formula (I): or a pharmaceutically acceptable salt thereof wherein: X is a phenolic opioid, wherein the hydrogen atom of the phenolic hydroxyl group is replaced by a covalent bond to —C(O)—Y—(C(R 1 )(R 2 )) n —N—(R 3 )(R 4 ); Y is —NR 5 —and R 5 is (1-4C)alkyl; n is 2 or 3; R 1 and R 2 are each hydrogen; R 3 is hydrogen or (1-4C)alkyl; and R 4 is a residue of an L-amino acid selected from alanine, arginine, asparagine, aspartic acid, cysteine, glycine, glutamine, glutamic acid, histidine, isoleucine, leucine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, lysine and valine; a residue of a dipeptide or tripeptide composed of two or three L-amino acid residues selected independently from alanine, arginine, asparagine, aspartic acid, cysteine, glycine, glutamine, glutamic acid, histidine, isoleucine, leucine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, lysine and valine; or a residue of an N-acyl derivative thereof.