The firm owned by the billionaire Sackler family is accused of helping fuel the US opioid crisis through drugs like painkiller OxyContin.
The deal would remove Purdue from the first federal trial over the opioids crisis, set to open in Ohio in October.
But the company could still face legal battles with states not in the deal.
Connecticut, Iowa, Massachusetts, Nevada, New Jersey, New York, Pennsylvania, North Carolina and Wisconsin are among those states saying they are not party to the agreement, the Associated Press reports.
The reported settlement is expected to be the largest ever paid out by an opioid manufacturer.
What is in the deal?
Purdue Pharma has been in negotiation to settle a case brought against it by more than 2,000 plaintiffs – including half the states, local governments and Native American tribes.
US media report the deal would involve the Sacklers exiting the company before it would file for bankruptcy, dissolve and reform.
Profits from the business would then be directed to pay plaintiffs an amount – thought to be around $10bn-12bn (£8bn-10bn) – as well as donating drugs for addiction and overdose recovery, multiple reports say.
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The Sackler family are expected to directly contribute at least $3bn of their own personal fortune to the deal, according to the reports.
The tentative agreement is thought to have the support of 23 states and about 2,000 local governments – but falls short of the national settlement Purdue had been seeking, according to the Washington Post newspaper.