GlaxoSmithKline (GSK) is selling its thrombosis drug brands and a related factory to South Africa's biggest generic drug maker Aspen Pharmacare for 700m pounds.The drug company has decided to let go of its Arixtra and Fraxiparine brands after experiencing falling sales. GSK said the disposal would earn proceeds of £600m and £100m of the headline price related to inventory which will be used for general corporate purposes.The group will retain the rights to the thrombosis brands in India, China and Pakistan.GSK owns an 18.6% stake in Aspen and first made the market aware of the deal in June. It comes after GSK sold its Lucozade and Ribena drink brands for £1.35bn to Japan's Suntory Beverage & Food earlier in September.Shares in GSK were down 0.32% to 1,563.50p at 14:10 on Monday.RD