Subject to the usual antitrust and regulatory approvals, UK drugmaker Glaxo SmithKline (GSK) has agreed to sell its portfolio of anesthetic drugs to South Africa’s Aspen Pharmacare Holdings for up to £280 million. The sale is part of GSK’s aim to focus on core therapeutic areas. Aspen will pay £180 million for the drugs Ultiva, Nimbex, Tracrium, Mivacron and Anectine, plus up to £100 million in milestone payments. GSK, which had previously sold the US and Canadian rights, earned £35 million from the anesthetics in the first half of 2016.

The sale comes as the two companies plan to end their collaboration in Sub-Saharan Africa, with Aspen exercising its option to acquire GSK’s remaining thrombosis business in certain retained markets which generated annual sales of around £30 million in 2015. The South African group bought most of the thrombosis rights in 2013 but GSK retained certain territories, including China, India and Pakistan.

A collaboration between the two firms in South Africa remains in place.