The private equity firms that own Quintiles Transnational plan to cash in some of their stakes.

The Durham drug-research company expects to sell $400 million in debt next week. Most of the money will pay a dividend to the investment firms, which include Bain Capital, TPG Capital and 3i.

Of that group, TPG helped Quintiles founder and CEO Dennis Gillings buy the company in 2003. Boston-based Bain and 3i, a British firm, bought out another equity firm's Quintiles stake in 2007. Financial terms weren't disclosed. Quintiles now has about $1.2 billion in debt.

Gillings, left, founded the company in 1982 while working as a professor at UNC-Chapel Hill. Quintiles had about $2.8 billion in revenue last year, and employs about 23,000 worldwide, including 1,400 in the Triangle.