Drug developer Skyepharma reported continued growth of its asthma inhaler Flutiform, but said royalties on some products were falling due to more competition.Skyepharma doubled sales of Flutiform compared with the second half of 2013 and launched the product in eight more countries including France in February, bringing the total number of nations where the product is available to 23.Four further countries including Spain also approved the drug in the first half.Revenue in the six months to 30 June rose 10% to £34.4m, with income from products launched since March 2012 comprising 62% of total revenues, up from 51% in the second half of last year.Operating profit increased 187% to £13.2m and pre-tax earnings before interest, depreciation and amortisation lifted 121% to £14.6m.Skyepharma said annual prospects were in line with the board's expectations and it expects second half revenue to rise compared with the first half driven by increasing momentum from products launched in the last two-and-a-half years.The group said, however, that established products were facing challenges."For the full year, the growth of royalties from recently launched products is likely to more than offset the decline in royalties from products which are facing generic competition in some markets," it said.The company raised £112m and fully repaid bond debt at a one-off cost of £25.5m.Net debt at 30 June was £2.9m, down from £84.2m at the end of December last year.Chief executive Peter Grant said: "With a strong financial position and momentum from a renewed revenue base, we are now in a position to invest further in new products, technologies and other corporate opportunities."Shares in Skyepharma fell 5.5p or 2.2% to 247.5p at 08:19 in London.PW