Pfizer will pay $550m upon completion of the deal to purchase the small molecule antibiotics division with add-ons and royalties to follow. Astrazeneca said that the sale will to support its strategy to focus on three core operations.
The announcement caps off a busy week for the developer of Viagra after it announced it was purchasing cancer specialist Medivation for $14bn on Monday.
"This agreement reinforces our strategic focus to invest in our three main therapy areas where we can make the greatest difference to patients' lives," said Luke Miels of Astrazeneca.
The sale will see Pfizer take on the global rights to five brands of the business unit however sales in the US are excluded.
"The addition of AstraZeneca's complementary small molecule anti-infectives portfolio will help expand patient access to these important medicines and enhance our global expertise and offerings in this increasingly important area of therapeutics, in addition to providing the opportunity for near-term revenue growth," said Pfizer's John Young.
Shares in Astrazeneca were subdued in early trading, edging down 0.67 per cent to 5,028p.