India’s pharma giant Ranbaxy has been charged with falsifying records and marketing poor quality generic medicines in the US.

The "pattern of systemic fraudulent conduct," the government said in court papers filed in Maryland, left an untold portion of the tablets and capsules made by Ranbaxy too weak, too potent or lacking the advertised shelf life. Late last year, Ranbaxy voluntarily recalled 73 million doses of a generic version of Neurontin.

In February 2007, federal agents raided Ranbaxy's North American headquarters in Plainsboro, New Jersey and a manufacturing facility in New Brunswick. The raid was prompted, in part, by problems uncovered in FDA inspections a year earlier at the company's plant in Paonta Sahib, India.

Officials at the plant in northern India fabricated test data to show their pain pills met Food and Drug Administration standards, Star Ledger newspaper reported.

"The government has reason to believe that these violations have resulted and continue to result in the introduction of adulterated and misbranded products" into the United States, federal prosecutors said in court papers, which asked the court to force Ranbaxy to turn over an internal review of its manufacturing operations in India.

The company declined, arguing the report is covered by "attorney-client privilege," the court papers said.

Charles Caprariello, a spokesman for Ranbaxy confirmed the federal investigation.

"We're still working with Food and Drug and the other authorities to resolve any questions," he said. "We've been conscientious in trying to provide information to the government.