Amersham to Buy Rest of Biosciences Venture

Amersham, the biggest maker of diagnostic imaging products, plans to pay about $1billion in cash for Pharmacia Corp.’s share of a joint venture after abandoning plans to sell stock in the unit.

The British company is exercising an option to buy the 45% it doesn’t own of Amersham Biosciences, a spokesman said. It’s selling as many as 57.5 million shares to fund the acquisition.

Amersham shares fell $2.74 to $49.66 on the NYSE. Shares of Peapack, N.J.-based Pharmacia rose 99 cents to $42.15, also on the NYSE.