The managing director of British American Tobacco's (BAT) business that develops e-cigarettes and nicotine inhalation products, Des Naughton, has decided to step down to focus on "new business opportunities", the cigarette maker said on Thursday.Naughton, who ran the Nicoventures business, will leave on 28 February after almost 20 years with the group."Des has built a strong foundation for the group for us to compete and win in next generation products," said chief executive Nicandro Durante."He, and the legacy he leaves, will be long remembered by his colleagues and friends in the company. On behalf of BAT, I thank Des for all he has done for the group."Kingsley Wheaton, currently group corporate & regulatory affairs director, will be appointed managing director of Next Generation products from 1 January.The group said it is a new role that will include the leadership of 'tobacco heating products' which will be managed alongside the emerging nicotine businesses.Wheaton has been with the company for 18 years and a member of the management board since 2012. Wheaton will be succeeded as group corporate & regulatory affairs director by Jerome Abelman, currently assistant general counsel of corporate & commercial.Neil Withington, group legal director & general counsel, is also leaving the company on 30 April. Shares fell 5p to 3704p at 09:47 in London.