Intellipharmaceutics International Inc IPCI.TO IPCI.O said on Monday the U.S. Food and Drug Administration (FDA) declined to approve its long-acting opioid painkiller in its current form, backing its independent advisory panel that had raised concerns over the drug's abuse-deterrence capabilities.

The decision comes at a time when the United States is battling with the opioid abuse crisis, which claimed more than 33,000 people in 2015, according to the Centers for Disease Control and Prevention.

The FDA asked Intellipharma to complete additional studies to assess the abuse-deterrent properties of the drug when used via oral and nasal methods, the company said.

Toronto-based Intellipharma's drug, Oxycodone ER, designed as a unique abuse-deterrent version of Purdue Pharma's oft-abused blockbuster OxyContin, contains a blue dye and a nasal irritant, that could help identify abusers and discourage misuse.

The FDA, however, requested additional information related to the inclusion of the blue dye in the drug.

The panel of independent advisers, which had voted 22-1 against approving the drug in July, had also raised questions about the ingredient's potential toxicity.

The company has been given one year to respond to the FDA's requests, Intellipharma said, adding that it can request additional time if necessary.

In an attempt to combat opioid abuse, federal authorities have implemented a slew of measures to limit the supply of such drugs, especially by requiring drugmakers to prove their painkillers deter abuse.

A number of states and local governments have filed lawsuits against opioid drugmakers and wholesale distributors holding them accountable for a national drug addiction epidemic.

In June, the FDA called for the removal of Endo International Plc's ENDP.O long-acting opioid painkiller, Opana ER, after a panel of advisers concluded that the drug's benefit did not outweigh its risks. It was the first time the agency had asked for the withdrawal of an opioid for public health reasons.

A month later, Endo withdrew Opana ER from the market.

(Reporting by Divya Grover in Bengaluru; Editing by Sriraj Kalluvila and Sai Sachin Ravikumar) ((Divya.Grover@thomsonreuters.com; within U.S. +1 646 223 8780, outside U.S. +91 80 6749 3859; Reuters Messaging: divya.grover@thomsonreuters.com.net))