"Purdue and the Sackler family need to take responsibility for their role in the opioid crisis," said Arizona Attorney General Mark Brnovich said in a statement.
The U.S. state of Arizona withdrew its support for a proposed nationwide opioid settlement with Purdue Pharma LP, saying the maker of OxyContin sought to "undermine material terms of the deal," according to a court filing on Monday.
Since Purdue filed for bankruptcy protection in September, Arizona is the first state to switch sides in the looming showdown over the privately-held company's proposed settlement, which it has estimated is worth more than US$10 billion.
Purdue reached the deal last month with 24 states and the local governments that have filed the bulk of the more than 2,600 lawsuits against the company.
The lawsuits accuse Purdue and its Sackler family owners of contributing to a public health crisis by aggressively marketing opioids while downplaying their addiction and overdose risks, which contributed to nearly 400,000 deaths since 1999, according to U.S. statistics.
Last week, court filings from states and local governments opposing the settlement asserted that Purdue steered up to US$13 billion in profits to the Sackler family, more than triple the amount previously cited in litigation.
U.S. Bankruptcy Judge Robert Drain in White Plains, New York, will on Friday consider Purdue's request for an injunction to pause the litigation for about nine months. Purdue said it needs time to try to settle the remaining cases.
Purdue also asked Drain to shield the Sacklers from litigation, even though they have not filed for bankruptcy, partly because the family has proposed contributing at least US$3 billion toward the settlement.
Opponents of the settlement accused the family of using Purdue's bankruptcy to shield their wealth from victims.
Separately on Tuesday, a Massachusetts judge ruled against the Sacklers, who sought to have the state's lawsuit against them dismissed. The judge rejected their argument they did not personally participate in Purdue's conduct.
Massachusetts was the first state to sue the Sacklers and Attorney General Maura Healey is leading the opposition to the proposed settlement.