Unless a drugmaker develops new compounds with its own research and development team, it has to pay up and license new drugs from other companies to keep its sales growing. King Pharmaceuticals (NYSE:KG), a prolific acquirer of other companies' drugs, announced yesterday that it had painlessly staked its claim to yet another.

In exchange for $3 million, King received the rights to a third unnamed abuse-deterrent opioid pain drug from small development partner Acura Pharmaceuticals (NASDAQ:ACUR). King and Acura first teamed up to develop pain drugs late last year.

Abuse-deterrent pain drugs are more resistant to tampering, and hopefully just as effective, as current commonly prescribed pain drugs like Perdue Pharma's OxyContin. Users sometimes abuse with these drugs by crushing them or dissolving them in liquid; King and Purdue hope to stop this practice with versions that lose their potency when not taken as instructed.

King and Acura revealed little about the third opioid compound they'll be developing. Acura did say that the drug had demonstrated "proof of concept," but not much else. Acurox, the lead drug in its King partnership, is an abuse-deterrent version of oxycodone in phase 3 testing, with a marketing application expected in the second half of this year. King also has a deal in place with Pain Therapeutics (NASDAQ:PTIE) for two similar abuse-resistant opioids, one of which is far along in testing and will hopefully produce an FDA marketing application later this year.

All of the abuse-deterrent drugs received a somewhat positive FDA advisory panel hearing earlier this month. If King had viewed that hearing negatively, it probably wouldn't be marching ahead with development of a fifth abuse-resistant compound, even if that decision's only costing it a few million dollars.