Mississauga-based biotechnology firm Biovail Corp. said Friday it has signed a series of pacts with Britain's GlaxoSmithKline PLC to become the Canadian distributor for popular drugs Wellbutrin SR and Zyban.

Wellbutrin is Glaxo's twice-daily anti-depressant drug. Zyban is an anti-smoking medication, prescribed to people addicted to nicotine.

As part of the deal, Biovail also has the option to market Glaxo's Wellbutrin XL, a once-daily anti-depressant, currently under review by the U.S. Food and Drug Administration.

Financial details were not disclosed.

Biovail said the total anti-depressant market in Canada was valued at over $450-million (U.S.) for the year ending Oct. 31 and is growing at a rate of about 17 per cent a year. About 18 million prescriptions were written for anti-depressants over the past year, reflecting year-over-year growth of 12 per cent, it said.

Combined annual sales for Wellbutrin SR and Zyban in Canada are expected to top $30-million this year and are "expected to grow significantly" through 2007, Biovail added.

In the United States, sales for Wellbutrin surpassed $1.4-billion for the 12 months ended October 31.

Separately, Biovail said it also signed a deal with Glaxo to extend its marketing rights for Zovirax Ointment and Zovirax Cream to 20 years from 10 years.

Biovail will pay Glaxo $40-million for the extension, it said.

Zovirax Ointment is used for the treatment of genital herpes while Zovirax Cream is used to treat cold sores.

Shares of Biovail currently trade around $41 (Canadian) on the Toronto Stock Exchange, at the bottom end of their 52-week range of $31.52 and $91.