Pharmaceutical company Pfizer has agreed to buy the small molecule antibiotics business of UK rival AstraZeneca in a deal potentially worth $1.5bn (€1.3bn, £1.1bn).

Confirming the move on Wednesday (24 August), Pfizer said it will pay $550m upon completion of the deal followed by a further unconditional $175m in January 2019.

Additionally, the US company could pay up to $250m in milestones, and up to $600m in sales-related payments and recurring, double-digit royalties on future sales of antibiotics brands Zavicefta and ATM-AVI in certain markets.

The AstraZeneca portfolio being bought by Pfizer also includes antibiotics brands Merrem, Zinforo and CXL.

In a statement, AstraZeneca said the sale agreement did not impact its financial guidance for 2016.