Patent ID: 8921418

Claim:
A method of treating or preventing pain comprising administering to a patient in need thereof an effective amount of a compound of structural Formula (I): or a pharmaceutically acceptable salt thereof wherein: X is a phenolic opioid agonist, 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 composed of two L-amino acid residues or a tripeptide composed of three L-amino acid residues, wherein the amino acids are 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.