What is "oripavine"

Oripavine is an opiate and the major metabolite of thebaine. It is the parent compound from which a series of semi-synthetic opioids are derived, which includes the compounds etorphine and buprenorphine. Although its analgesic potency is comparable to morphine, it is not used clinically due to its severe toxicity and low therapeutic index. Owing to its use in manufacture of strong opioids, oripavine is a Schedule II controlled substance under the Controlled Substances Act 1970, with an ACSCN of 9330 and a 2013 manufacturing quota of 22 750 kilos.