The sale, which completed today, includes the approved antibiotics Merrem, Zinforo and Zavicefta, as well as two antibiotics still in clinical development, ATM-AVI and CXL.
Pfizer will pay a further $175m in January 2019, up to $250m in commercial, manufacturing and regulatory milestones, up to $600m in sales-related payments as well as double-digit royalties on future sales of Zavicefta and ATM-AVI in certain markets.
The sale of the commercialisation and development rights to the small molecule antibiotics branch was announced in August.
Last month, AstraZeneca posted weak quarterly profits, with operating profit down 29 per cent to $1bn, following increased competition in the sector.
However, big pharma companies are expected to benefit from a Trump presidency and as AstraZeneca makes around half its total sales in the US, it could be poised for a better few years ahead.
AstraZeneca shares were unmoved at the open, falling 0.2 per cent to 4,335p.