U.S. drug wholesaler AmerisourceBergen Corp. said Tuesday it will pay $520 million in cash to buy privately held World Courier Inc., a global specialty transportation and logistics provider for biopharmaceutical companies.

Amerisource, based in the Philadelphia suburb of Valley Forge, Pa., said the deal -- the latest in a string of acquisitions -- is expected to close no later than September of this year.

The company's latest completed acquisition was the purchase of CVS Caremark Corp.'s TheraCom LLC unit, according to The Wall Street Journal.

The World Courier deal, which is subject to regulatory approvals, will be neutral to Amerisource's fiscal 2012 earnings and add to the following fiscal year's earnings, said the company, which has more than $80 billion in yearly revenue and employs 11,000 people.

Buying World Courier strengthens AmerisourceBergen's reach outside North America, AmerisourceBergen said.

Stamford, Conn.-based World Courier has projected annual earnings for calendar 2012 of about $500 million.

It was founded in 1969 and is the largest specialty logistics company with a network of 137 wholly owned ISO 9001-certified offices in 52 countries.  It also operates an extensive integrated company-owned network of GMP-compliant investigational drug storage facilities in 13 locations.