Now we are witness to carfentanil being added to fentanyl to increase it's potency. Carfentanil is some x100 more potent than fentanyl and as I have remarked elsewhere, I feel that law enforcement should class it as a WMD (as the Royal Collage of Anethentists has suggested). It seems that even the threat of decades in prison isn't stopping the people making it. Being treated as a terrorist just MIGHT make them think again.
I might add that there is a compound listed in the CWC that is still used medically, so it's clear that the legislation to allow exceptions is already in place, so nobody can claim it cannot be done. Legitimate uses of carefentanil exist but are so rare, licencing would not be an issue.
BTW recently I noted a dodgy website were apparently offering a compound they claimed to be at least as potent as cafentanil. But it's not. Or, rather, I should say that in animal models it's analgesic activity is around the same as carefentanil, but the compound being offered is a selective NOP ligand and the key point mentioned in one paper is 'did not substitute for morphine in animal models' in that animals wouldn't self-administer the stuff suggesting that it isn't psychoactive, or at least not in a posivie manner.