ConvaTec develops and markets wound therapeutics and ostomy care products. The company has more than 850 employees working at its Deeside factory and research centre.
Chief Executive Dave Johnson said the jobs at its Welsh sites were secure and it is possible that the new owners would make a substantial investment in due course. Funds of £25m have already been invested into a sister plant at Rhymney, south Wales.
The sale is subject to adjustment based on ConvaTec’s audited 2007 financial statements. Avista has offices in New York and Houston, while Nordic Capital is based in Stockholm, Copenhagen and Hellsinki.