U.S. biotech company Amgen is to buy Turkey's Mustafa Nevzat Pharmaceuticals, a maker of injectable generic drugs, for around $700 million in a deal underscoring Western drugmakers' thirst for emerging markets sales.

The purchase, announced by both companies on Wednesday, is the latest in a string of acquisitions by international drug companies - both at home and abroad - as they try to buy growth to offset patent expiries and price cuts.

Sales of pharmaceuticals are growing faster in emerging markets than in Europe and the United States, making them attractive to companies like Amgen.

Later on Wednesday, Watson Pharmaceuticals is expected to announce a deal to buy Swiss-based Actavis for around $6 billion, helping it compete against larger rivals and also increasing its exposure to emerging markets.

At the same time, companies like GlaxoSmithKline and AstraZeneca are stepping up their drive to acquire smaller biotechnology companies with promising new drugs to improve their pipelines of high-priced patented medicines.

Under the all-cash agreement between Amgen and MN Pharma, Amgen will acquire 95.6% of the shares in the privately held Turkish company for an amount that values MN Pharma at $700 million.

"Together with MN's staff and management team, we plan to grow our business with high quality and innovative medicines in Turkey and the surrounding region," said Amgen Chief Operating Officer Bob Bradway.

Bradway will step into the position of chief executive officer next month when current CEO Kevin Sharer retires.

Export business

People familiar with the situation said Amgen competed with a number of rivals to acquire the Istanbul-based firm, although Britain's GlaxoSmithKline - seen at one stage seen as a strong contender - was not interested in the end.

MN Pharma came into play as a takeover target after Eli Lilly discussed a possible partnership deal last summer. But those one-on-one discussions finally fell apart, prompting the family owners of MN Pharma to start the wider auction process.

The owners hired Bank of America Merrill Lynch as adviser on the sale.

MN Pharma is the leading supplier of drugs to the hospital sector in Turkey and a major supplier of injectable products. It also has a fast-growing export business.

MN Pharma said in a statement that revenue totalled around $200 million in 2011 and it had been growing on average at more than 10% a year in local currency over the past five years.

MN Pharma is one of the leading and oldest pharmaceutical companies in Turkey. It was established in 1923 by Mustafa Nevzat Psak and was the first Turkish drug company to be granted the U.S. Food and Drug Administration approval for active pharmaceutical ingredients (API) and finished dosage forms of medicines in 2006.

It has a workforce of 1,200.

Past Turkish drug deals include Zentiva, a Czech drugmaker bought by Sanofi in 2009, acquiring 75% of the generic drug unit of Turkey's Eczacibasi in 2007 for €460 million ($607 million). It later bought out the remaining 25%.