The letter, issued in February and recently released by the FDA, details a series of good manufacturing process (GMP) violations that resulted in drugs products manufactured in the Totowa facility being deemed 'adulterated' under FDA regulations.

The quality control unit at the site came under heavy criticism from the agency, failing to reliably establish the identity, strength, quality and purity of drug products manufactured and released onto the market.

The FDA inspectors also noticed a general lack of investigation of out-of-specification test results, as well as a lack of sufficient documentation of the results. In addition to this, the agency states that products were released onto the market following re-testing, with no explanation for dismissing the original out-of-specification results.

The company fell down further by ignoring or failing to recognize tablets that did not meet in-process requirements, with no evidence that process deviations received prompt attention to prevent sub-standard products reaching consumers.

For example, in May last year a batch of the company's hydrochloprothiazide tablets failed to achieve target hardness. The batch passed quality control, and when it failed to meet yield specifications in April it was put down to broken tablets and the batch released.

Another issue highlighted by the FDA was that Actavis' cleaning validation studies were found to be somewhat lacking. The inadequacies regarding the company's cleaning processes prompted the agency to note that there is thus no assurance that equipment is sufficiently cleaned between the manufacture of different drug products.

Other blunders on the part of the company included re-qualification of machinery without adequate documentation and information, and failures to establish and follow written procedures for maintenance of manufacturing equipment.

One machine was reported to be strapped up with duct tape to prevent powder escaping during production.

Actavis has responded to FDA several times since the inspection was carried out last summer. However, the agency seems wary of the firm's promises to address the issues raised by the investigation

In the recent warning letter, the FDA states:

"We are concerned about the quality of drug products that have been released from your facility under the serious lack of current GMP controls found during the inspection."

In order to provide some assurance that the deviations noted by the agency will be tackled, the FDA suggests that the firm promptly employ the services of an appropriately qualified third party to conduct a quality system audit program.

No representatives from Actavis were available for comment by the time of going to press.