Under the terms of the deal, CD&R will pay £10.23 in cash per share in UDG.
Headquartered in Dublin, UDG Healthcare provide healthcare advisory, communications, commercial, clinical and packaging services.
UDG Healthcare chairman Shane Cooke said: “We believe that this is an attractive offer for UDG shareholders, which secures the delivery of future value for shareholders in cash today.
“The offer reflects the quality, strength and long term performance of UDG’s businesses and its future growth potential.
“We believe that our people, our clients and our businesses will continue to prosper under the stewardship of CD&R.”
Employing about 9,000 people in almost 30 countries, the firm has two divisions – Ashfield and Sharp.
CD&R partner Eric Rouzier said: “UDG has long established itself as a leading provider of high-value services to pharma and biotech companies globally, supported by a highly skilled workforce.”
Following shareholder and regulatory approvals, the deal is expected to be declared effective during Q3 2021.
During the half-year results to the end of March 2021, UDG posted adjusted pretax profit increase of 10% at $82.4m on revenue drop of 5% at $661.4m.
Ashfield posted an increase in adjusted operating profit by 7% compared with the same period of last year, while Sharp’s adjusted operating profit grew by 19%.
UDG said its board is not proposing an interim dividend for 2021.
The firm divested its supply chain business in 2015.