In a pre-negotiated share sale agreed a year ago, Japan's Daiichi Sankyo has unloaded its entire 8.9% stake in India's mammoth generics producer Sun Pharmaceutical Industries, raising 200 billion rupees ($3.2 billion).

Indian media reported that Dilip Shanghvi, Sun Pharma's founder, was among the buyers of the Daiichi shares.

The sale closes the final chapter of the Japanese drugmaker's 2008 acquisition of India's Ranbaxy, which was acquired in full by Sun in March of this year.

Observers of the deal said Daiichi Sankyo profited from the 80% increase in the value of its Sun shares since the Ranbaxy deal was announced, allowing it to recoup almost all of the rupee-denominated original acquisition price.

In buying Ranbaxy, Daiichi Sankyo had hoped to cash in on the generics boom, but instead found itself having to write down $3.7 billion half a year later when the extent of the US Food and Drug Administration's sanctions against the company for manufacturing irregularities became public.

Noting that Sun Pharma has a record of acquiring troubled drugmakers and returning them to profit, media reports quoted Shanghvi as saying the company's priority is to regain the trust of US Regulators.