Vintage has received another warning letter from the US Food and Drug Administration (FDA) detailing a number of violations in current Good Manufacturing Practice (cGMP) including "failure to adequately investigate evidence of microbiological contamination and failure to maintain a complete record of data secured in the course of each test."

The letter asks the company to explain why a response to an August 8, 2007 FDA 483 form - sent out after an on-site audit and in which the field inspector lists deficiencies of a company's quality systems - did not explain why the test results were not documented. Vintage filed a response to the 483 form on September 6, 2007.

The FDA has also censured Vintage for not adhering to its own standard operating procedures (SOPs) when carrying out microbiological testing, including from air samples in the production facility, and a "failure to establish scientifically sound and appropriate test procedures designed to assure in-process materials and drug products conform to appropriate standards of identity, strength, quality, and purity."

And Vintage stands accused of releasing batches of the unidentified component for use in the manufacture of a finished drug product before being signed off by the quality control department.

Vintage, based in Huntsville, Alabama, has received multiple warning letters over the last few years citing deficiencies in its manufacturing operations and concerning a wide range of products. In 1998 the company was placed under a consent decree, but has been unable to put its house in order.

In 2001 it was forced to recall lots of levothyroxine because of stability and potency problems. In 2006 Vintage pleaded guilty to felony charges of distributing 50 million levothyroxine tablets in the knowledge that they were were mislabelled with 12-month expiration dates that did not reflect the product's stability data, receiving a $4.8m fine and forfeiting $1.2m in proceeds from the activity.

And last year the FDA ruled that the firm's ergotamine-based Bellaspas product for migraine was no longer covered by its New Drug Application, and that Vintage would have to file another NDA in order to continue to sell the product.