The Walgreens Boots Alliance Friday said the drug store chain is going private, acquired by private equity company Sycamore Partners in a $23.7 billion deal described as a "definitive agreement."

Walgreens Boots Alliance will be taken private by Sycamore Partners for $10 billion, the buyout firm said on Thursday, closing out nearly a century of trading on public markets for the U.S. pharmacy giant.

Shares of Walgreens Boots Alliance have lost about half their value in the past year, as the chain has faced pressure in its retail and pharmacy businesses.