Development of novel pain relief agents acting through the selective activation of the delta-opioid receptor

A continuing effort in the development of non-peptide delta-opioid agonists as possible safe and effective pain relief agents has been seen in the last years. Novel potent and selective delta-opioid agonists based on the pirrolomorphinan framework have been designed, synthesised and biologically characterised in our laboratories. In particular, compound 7 (SB 235863) proved the concept that a selective delta-opioid agonist may be a valuable pain relief agent free of the unwanted side-effects usually associated with narcotic analgesics such as morphine.