Mumbai: A US federal court in West Virginia has ordered Purdue Pharma to pay $634 million in settlement to defendants in claims over OxyContin drug.

The court also sentenced three top executives of Prude Pharma that makes the narcotic to three years'' probation and 400 hours each of community service in drug treatment programmes.

Stamford, Conn-based Purdue Pharma acknowledged that its staff had violated prescription requirements for its OxyContin painkiller. The company also acknowledged that its "fraudulent conduct caused a greater amount of OxyContin to be available for illegal use than otherwise would have been available."

Judge James P. Jones of the US district court who heard testimony from parents of young adults who died from overdoses involving the painkiller OxyContin indicated that he was troubled by his inability to send the executives to prison.

Those testified at the hearing also included some patients who testified about the pain relief they had received from OxyContin.

Federal prosecutors had failed to produce evidence as part of a recent plea intended to show that officials at the drug maker were aware of wrongdoings.

Purdue Pharma said the three "top executives" would be charged with felony. The company said that it would also be charged with a felony.

The $634 million represents 90 per cent of the profits for OxyContin sales during the time of the offence.

OxyContin, which is a long-acting, time-release form of the narcotic oxycodone, is used to treat serious pain. Several reports have suggested that Purdue may have helped fuel widespread abuse of the drug by aggressively promoting it to general practitioners not skilled in either pain treatment or in recognising drug abuse. The company has denied such a connection.

Both addicts and young experimenters quickly discovered that a pill needed only to be chewed or crushed before ingesting to release large doses of oxycodone, which produces a heroin like high. The misuse of the drug OxyContin exploded in early 2000, just a few years after it was first sold.

Survivors of the victims want the US Food and Drug Administration to reclassify OxyContin for use only for severe pain. The drug currently can be prescribed for moderate pain.

The ruling, however, may no mean an end op Purdue Pharma''s legal problems. A clutch of insurers had sued it, seeking compensation for what they contend were unnecessary prescriptions for OxyContin, a very expensive drug that were written because of the company''s false marketing claims.