Ranbaxy Laboratories, the Indian unit of Japan's Daiichi Sankyo, will restart production of its generic version of cholesterol-lowering drug Lipitor for supply to the US market, three months after it recalled the drug from the US.

In November last year, Ranbaxy's US subsidiary, Ranbaxy Pharmaceuticals Inc, recalled 41 lots of its generic version of Lipitor from the US market after finding small glass particles in some lots of Atorvastatin, the generic name for Pfizer's blockbuster drug Lipitor. (See: Ranbaxy recalls generic Lipitor in US market over glass particles in bottles)

The recall was select lot numbers of Atorvastatin of 10mg, 20mg, and 40mg dosage strengths, packaged in 90's and 500 count bottles. The recall did not affect the 80mg strength dosage.

The recall was only for the US market and not other markets across the world.

In a filing with the stock exchanges, the Haryana-based company said, "We are working with the US FDA, and have identified and implemented multiple corrective and preventative actions (CAPA).

As part of the first step in initiating the manufacturing process to resume supplies to the US market, we have commenced the production of the drug substance for our Atorvastatin product."

Ranbaxy was the first to market the generic version of Lipitor in late 2011 after US drug giant Pfizer lost its US patent protection on 30 November 2011.  Prior to the patent expiration, Lipitor was the world's top selling prescription drug with annual peak sales of about $13 billion.

Ranbaxy was given rights to 180 days of marketing exclusivity by the FDA for being the first to file for a generic equivalent, and in first six months on the market, the drug generated sales of nearly $600 million for Ranbaxy.

Ranbaxy and US-based Watson Pharmaceuticals, which had been authorised by Pfizer to sell a generic version of Lipitor, were the two companies that had exclusive rights to sell the generic version of Lipitor for six months in the US.

The recall benefited five other manufacturers in the US including Watson and Pfizer since Ranbaxy held around 43 per cent market share in the US for Atorvastatin. It has been reported that since it stopped production, its market share for the drug has since fallen to 3 per cent.

Ranbaxy has recently been targeted by the FDA over its manufacturing practices and quality controls at several plants in India and the US.

It has also been hauled up by the FDA for falsifying data and test results in approved and pending drug applications, which could lead to defective products.

In January, the US Department of Justice obtained a decree from a federal judge banning Ranbaxy from producing some generic drugs, but not the generic version of Lipitor, in the US market until it corrected the problems at its plants.