Packaging Coordinators (PCI) has signed an agreement to acquire the UK-based Penn Pharmaceutical Services for around £127m.
PCI is buying the stake from mid-market private equity firm LDC, which has been an investor in Penn Pharma since in 2007.
Considered to be one of the oldest pharmaceutical companies doing business for 30 years, Penn Pharma provides drug development, manufacturing and packaging services.
The privately owned company operates from a facility in South Wales and employs around 300 workers. It operates regional offices in Pennsylvania, US and Tokyo, Japan.
Penn Pharma launched a manufacturing and packaging expansion project this year and opened a £14m purpose-built manufacturing facility in 2013.
Penn Pharma CEO Richard Yarwood said: "By combining the expertise and resources of PCI and Penn Pharma, we are able to offer exceptional outsourcing solutions to the international healthcare industry.

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By GlobalData"This is a very exciting time, the specialist expertise from Penn together with the experience and global footprint of PCI will provide even more opportunities to support our customers."
Owned by Frazier Healthcare, PCI provides packaging services for pharmaceutical products in more than 100 countries and has offices in the US and the UK.
The company is currently undertaking cold chain infrastructure expansions for storage and logistics and support for refrigerated packaging operations.
Packaging Coordinators president and CEO Bill Mitchell said: "With Penn Pharma’s services, we can partner with clients at the very earliest stages of drug development to support them with drug formulation, analytical development, drug manufacturing, clinical packaging, global distribution, and ultimately supporting the product’s commercial launch.
"This addition expands our vision of lifecycle support from clinical trials through commercialisation for our clients’ lifesaving therapies," added Mitchell.