Sun announced the 483 in a filing on the Bombay Stock Exchange (BSE) today.
The firm said: “We confirm that our Halol facility has undergone an inspection by US FDA recently. The inspection was completed on 01-December-2016.
“A Form-483 observation letter was issued by the US FDA post the inspection. We are currently in the process of responding to the said letter to the US FDA within the stipulated timeline of 15 days.”
The US Food and Drug Administration (FDA) has a complex relationship with Sun’s Halol site.
In 2012, the agency temporarily allowed Sun to produce a generic version of the cancer drug Doxil (doxorubicin hydrochloride) at the site for the US market as a result of shortages caused by the problems at J&J's supplier Ben Venue.
Since then the FDA’s view of the Halol plant has been less positive.
Last September agency inspectors found incomplete records during a surprise visit to the site, prompting Sun to begin implementing corrective measures.
The Elepsia XR approval was viewed as an indication these efforts were working although – as analysts pointed out during an earnings call last month – when the US FDA rejected Sun’s Xelpros (Latanoprost) in August it cited ongoing problems at the facility.
Last December, Sun announced it received the US Food and Drug Administration (FDA) warning letter on December 19, explaining that it was issued in response to observations made by the agency during an inspection in September 2014.
The Indian drugmaker said it had called in external consultants and is working to address the problems identified during the 2014 inspection.