Routes the original could not reach, from Russian work

Deigin's Moscow group took the chain and locked it into ring-shaped diketopiperazine structures to stabilise it, then showed the new analogues working given into the nose in rats and by mouth in mice, with dose-dependent pain relief at remarkably small amounts. Getting an opioid peptide to work through the nose or the stomach has defeated this field for forty years. That work is where the molecule's future most likely sits.