Canadian drugmaker Valeant Pharmaceuticals has signed a deal to acquire dermatology specialist Obagi Medical Products in a deal valued at around $344 million.

The $19.75-per-share deal is expected to close in the first half of the year and boost Valeant's dermatology business with a number of topical aesthetic and therapeutic products with sales of around $120 million last year.

Valeant has been following a strategy of growth by acquisition for some years and has been concentrating on dermatology of late, buying skincare specialist Medicis last September for $2.6 billion in a deal that brought in acne treatments and wrinkle treatment Dysport (abobotulinumtoxin A).

The company lost out to Teva in a bidding war for Cephalon in 2011 but has been busily buying up companies in dermatology as well as other speciality areas such as ophthalmology, dental and over-the-counter (OTC) medicines.

Prior to the Obago and Medicis purchases Valeant paid $345 million for Johnson & Johnson's Ortho Dermatologics and $425 million for Sanofi's Dermik skincare business for example. The strategy has allowed Valeant to post big rises in annual revenues - last year sales advanced 44% to $3.55 billion - although the costs of acquisitions resulted in a net loss of around $116 million.

"The acquisition of Obagi will be a valuable supplement to Valeant's current dermatology portfolio and will further build upon our growing aesthetics franchise," said Michael Pearson, Valeant's chairman and chief executive. 

"Obagi is a leader in the physician dispensed market and enjoys a strong brand perception among physicians," he added.

The company's brands include the Nu-Derm range of moisturisers and prescription products such as its Condition & Enhance products, which are made available by dermatologists and plastic surgeons.

Valeant said its latest deal would immediately be accretive to earnings and provide cost synergies of around $40 million.

Meanwhile, further acquisitions are likely to be on the cards. Pearson told investors on its annual results call late last month that while there were no major gaps in its product portfolio "we'd like to get bigger; a lot bigger."