The manufacturing base of the group is at Inverin, Co Galway.
Up to 160 people are employed and staff were informed of the sale yesterday, according to a reliable source. It is understood that the business will be developed further by the new owners.
At the briefing yesterday, there was no mention of job losses.
Bioniche has been owned by US private equity firm RoundTable Health Partners since the beginning of 2006. It manufactures injectable pharmaceutical products, which serve a variety of niche markets globally.
Jack McGinley, founding partner of RoundTable and group chairman said: “We believe Mylan is an excellent strategic partner for the company, its employees and customers.”