Ranbaxy, which is 63.5 per cent-owned by Japan's Daiichi Sankyo Co and gets more than 40 per cent of its sales from the United States, did not immediately respond to a request on Wednesday for comment on the FDA observations.
US stocks rose more than 1% on Tuesday, with the S&P 500 coming less than 2% below its record peak set last month.
And when an inspector asked about the contents of unlabelled vials in the laboratory glassware washing area, a plant worker dumped them down a sink and said the contents could not be determined, according to a July 18 letter from the US Food and Drug Administration to Wockhardt, which makes sterile injectable drugs and various forms of insulin.
There are just 1,500 drug inspectors responsible for more than 10,000 factories in India