Ranbaxy on Tuesday announced it had got final approval from the US Food and Drug Administration to market its Metformin HC1 tablets for diabetes.

The approval was granted after Barr Laboratories, a wholly owned subsidiary of Barr Pharmaceuticals Inc, selectively waived its rights to their exclusivity in favour of Ranbaxy.

The shipment of the product had already begun within the US, a company release said.

The USFDA had determined the Ranbaxy formulation -- Metformin Hydrochloride Extended-release Tablets, 500 mg -- to be bioequivalent and having the same therapeutic effect as that of the reference listed drug Glucophage, XR tablets of Bristol Myers Squibb Company, it said.

The total market sales for the tablet are estimated at $363 million.