Pharmaceutical company Vertical/Trigen Holdings LLC, backed by Avista Capital Partners, has agreed to merge with Osmotica Holdings Corp. for an undisclosed amount.

Vertical/Trigen is the parent company of Vertical Pharmaceuticals and Trigen Laboratories. Vertical, based in Sayreville, New Jersey, is known for its Nexa and OB Complete women’s health, Corvite vitamin supplements, and Lorzone pain management brands. Trigen is the company’s generic drugs division. Avista acquired a majority stake in Vertical/Trigen in 2013 when it invested alongside management.

Osmotica, located in Marietta, Georgia, is a pharmaceutical company that focuses on treating movement disorders, such as Parkinson’s disease. The combined company will have Osmotica's name and will be jointly owned by Vertical/Trigen and Osmotica.

Avista is a middle-market private equity firm that focuses mostly on the health care, energy and communication sectors. The firm has offices in New York, Houston and London.

Buyer interest for generic drug distributors has been picking up lately. Cardinal Health Inc. is adding Harvard Drug Group; Cipla Ltd. (NSE: CIPLA) is buying InvaGen Pharmaceuticals Inc. and Exelan Pharmaceuticals Inc.; and Teva Pharmaceutical Industries Ltd. (TLV: TLVA) is purchasing Representaciones e Investigaciones Médicas SA.

Jefferies LLC and Covington & Burling LLP are advising Osmotica. Weil Gotshal & Manges LLP is representing Vertical/Trigen.