Antitrust regulators in the U.K. yesterday opened a probe into the planned merger of Nelipak and Bemis Healthcare Packaging Europe by private equity shop Kohlberg.

The PE giant acquired Cranston, R.I.-based Nelipak, which manufactures rigid healthcare packaging used in Class II and Class III medical devices and pharma drug-delivery products, in early July for an undisclosed amount.

Last week Mount Kisco, N.Y.-based Kohlberg also picked up Bemis, likewise for an undisclosed amount, and said it planned to merge the U.K.-based company with Nelipak under the Nelipak Healthcare Packaging brand.

That prompted the U.K.’s Competition & Markets Authority to open its anti-monopoly investigation into the proposed merger, the agency said yesterday in a pair of announcements.