REFILE-Madison Dearborn in the lead to take over Walgreen unit -sources
December 19, 2014 at 16:11 PM EST
Dec 19 (Reuters) - Buyout firm Madison Dearborn Partners LLC is in advanced talks to acquire a majority stake in the infusion services business of U.S. drugstore chain operator Walgreen Co for more than $1 billion, according to two people close to the situation.