Auxilium Pharmaceuticals Inc. (Nasdaq: AUXL) has purchased Actient Holdings LLC from private equity firm GTCR LLC for $585 million.

Actient, headquartered in Lake Forest, Ill., develops medicines that treat urological conditions. Since GTCR’s ownership in March 2009, Actient made five acquisitions, including Striant, a testosterone replacement medication and Timm Medical Technologies Inc., a company that provides products to treat erectile dysfunction.

Chesterbrook, Pa.-based Auxilium develops and markets pharmaceutical products to treat low testosterone and Dupuytren’s Contracture, a thickening of the skin in the hand area.

Chicago-based GTCR focuses on investing in financial services, technology, health care and information services companies. The firm has invested more than $10 billion in about 200 companies. GTCR’s portfolio companies include Devicor Medical Products, Heritage Golf and Rural Broadband Investments. Through Rural Broadband, GTCR bought NewWave Communications in February. 

Jefferies was Actient's financial adviser for the deal. Morgan Lewis & Bockius LLP with Wilkie Farr & Gallagher LP advised Auxilium.