Dermorphin
It is a heptapeptide from Phyllomedusa frog skin that is approximately 40 times more potent than morphine at the mu-opioid receptor. It is not FDA-approved for any human use, has no IND or NDA on file, and the entire human clinical evidence base consists of one unreplicated 1985 intrathecal trial of 150 postoperative patients that has never been advanced to Phase II or Phase III development.






