There was a frenzy of activity in the pharmaceuticals sector today.

British giant GlaxoSmithKline paid £486 million to Belgian biotech firm UCB to sell some of its products in emerging markets, while the biggest company in the sector, Viagra maker Pfizer, was revealed to be in £43 billion merger talks with US rival Wyeth.

Glaxo's deal will allow it to sell UCB's epilepsy drug Keppra and allergy medicine Zyrtec, but does not include the Belgian firm's pipeline drugs.

In 2008, the acquired drugs represented between 3% and 4% of UCB's £3.09 billion revenue.

The acquisition will boost the British firm's presence in emerging markets in the Far East, Middle East, Africa and Latin America.

By 2020, emerging markets are forecast to account for 40% of growth in the worldwide pharma market.

"This acquisition will strengthen and expand GSK's product portfolio in these emerging-market countries, and help us to meet the needs of patients, particularly in the areas of epilepsy and respiratory," said Abbas Hussain, head of emerging markets at GSK.

The drugs industry has been one of the busiest sectors of the year, with rumours about mergers and buyouts as the giants face looming expiry of patents and are looking to fill gaps in their pipelines.

Glaxo bought BMS Pakistan in December.