A North-East medical research company is about to tap into a multi-billion pound market with a device to help millions of people beat a common winter ailment.

Sufferers across the UK are already benefiting from the hand-held gadget, Virulite CS, which is revolutionising the treatment of cold sores.

Ten years of research, development and testing went into the product, invented by Dr Gordon Dougal, a medical doctor and engineer, and Jim Haslam a consultant ophthalmologist, who are both directors of Durham-based Virulite Limited.

Now they are preparing to launch the product across Europe, the United States, Australasia and Japan.

Solicitors with regional law firm Blackett Hart and Pratt are drawing up distribution agreements that will take the product into the biggest world markets.

The American market alone, where 50 million people suffer from recurrent cold sores, is expected to be worth millions of pounds.

A distributor is poised to begin retailing Virulite CS in the USA, Australasia and Japan as soon as the Federal Drug Administration approves the product.

The FDA is awaiting clinical evidence of its effectiveness based on trials currently ongoing at seven GP practices in the North-East.

Dr Dougal said: "Once you start giving people your products to sell they have the right to distribute them. We have had a lot of interest from distributors, but you have to know if they are capable of performing. If they don't perform, you need contracts that allow you to switch distributor."

Virulite Ltd is also identifying distributors in Europe who have the finance and capability to launch the device.

Currently available in the UK online, Virulite CS is a natural therapy which is said to have no side effects.

Clinical trials over three years, including one supervised by the University of Teesside, have shown it works three times as fast as cold sore creams.

Dr Dougal said: "It not only works faster, but lasts longer and is therefore cheaper than current medicinal products, which is rare in this market. We have applied for NHS approval and, once we have that, the product will be available in chemists across the UK."

Held against the skin, Virulite CS works by emitting low energy infrared light on the area of the cold sore. A built-in timer ensures a three-minute treatment cycle. At the end of the treatment, the device switches off.

The device also helps the body build up resistance to the virus, preventing the recurrence of cold sores in the future.