Officials in Alberta have been warning about a deadly drug called W-18 creeping into the province -- but as it turns out, the drug was invented there in the first place.

Scientists at the University of Alberta in Edmonton created the compound more than 30 years ago.

Officials say the drug is 10,000 times more powerful than morphine and 100 times more potent than fentanyl.

Edmonton police seized four kilograms of powdered W-18 in December, before it could be manufactured into pills. They said it was enough of the drug to produce hundreds of millions of illicit doses.

Originally, the drug was intended to be a painkiller.

"This drug was found by people that were interested in making new analgesics, and that's what the patent is called,” said pharmacology professor Bill Colmers. “So they made a bunch of drugs that are based on the structure of morphine."

Edward E. Knaus, Brent K. Warren and Theodore A. Ondrus filed a patent for W-18 in 1982, but the drug was never picked up by a pharmaceutical company.

Now that the patent has expired, forensic chemist Brian Escamilla says chemists in China have resurrected it for the wrong reasons.

“Chemists are then going back now and finding these old patents and resynthesizing these compounds in an effort to sell -- in this case, if you want to call it that -- a legal high.”

W-18 is not technically regulated in Canada, though Health Canada says it’s moving quickly to include the synthetic opioid in the federal Controlled Drug and Substance Act.

The government does, however, say the drug is already illegal under another law.

With files from CTV Edmonton and the Canadian Press