The Galashiels business is being backed by its Tokyo-based parent Kyowa Hakko Kirin (KHK) in the transaction to buy Archimedes Pharma.
Tom Stratford, ProStrakan chief executive, believes the acquisition will lead to further strong increases in revenue with the firm having previously announced a 20 per cent hike in turnover to £155m for 2013.
Archimedes, which has its headquarters in Reading and a development facility in Nottingham as well as a presence across France, Germany and Spain, had itself recorded a 33 per cent rise in revenue to £41 million last year.
Mr Stratford said: "I actually think the businesses will be even stronger in a combined position. There is a great fit with our business and their business.
"It is very much a growth strategy. We see new brands, new people and growing revenue."
The main product produced by Archimedes is a nasal spray called PecFent which is used to help alleviate pain in cancer patients and has been used by NHS Scotland since 2011.
ProStrakan's own product range includes an anti-nausea patch for cancer sufferers called Sancuso.
Mr Stratford said the deal brings a lot of attractive intellectual property and patents.
He feels PecFent has a "great opportunity" ahead of it in terms of growing sales while there are plans to look at taking the Archimedes product line beyond Europe.
He said: "We'd definitely be potentially looking to the US but also towards Asia and Japan where our parent group is.
"I think there will be plenty of opportunity for some of those brands in those areas."
Alongside that Mr Stratford was keen to stress the additional scale of human resource for sales and marketing across Europe.
ProStrakan's workforce stands at about 300, with about one-third of those in the Scottish Borders. Archimedes has in the region of 160 staff.
Mr Stratford is confident that will give ProStrakan a strong base to build its operations on in the coming years.
He said: "The acquisition of Archimedes represents a rare opportunity to enhance the scale of our successful European operations by adding a strong portfolio of high-value medicines as well as further strengthening our teams in major European markets. That prepares us really well for the longer term future products and novel drugs that KHK has coming down the pipeline."
Among the drugs KHK is working on is a tablet to help Parkinson's patients with the symptoms of their disease and another product which involves antibodies designed to combat cancer.
Although the deal is being funded by KHK, Mr Stratford said it had been initiated and led by the Scottish company.
He admitted ProStrakan had been looking at deals for quite a while but started working seriously on putting together an offer for Archimedes in the past few months.
He said: "ProStrakan identified the opportunity, worked with our banking team and legal team here in the UK to run the process and complete. Obviously with close dialogue with our colleagues in Tokyo.
"It demonstrates a great trust and support from the parent company and also demonstrates that ProStrakan has earned that trust to give KHK the confidence to make such a big investment."
Lazard acted as financial advisor to KHK and ProStrakan with Wragge Lawrence Graham & Co the legal counsel.
KHK paid around £292m to buy ProStrakan, which had been listed on the stock exchange, in 2011.
The Archimedes owner, Danish private equity firm Novo A/S, has agreed to sell the business although the deal still has some minor regulatory hurdles in Germany to clear before being formally completed.