Speciality plastic and fibre products supplier Filtrona said trading conditions in its markets have stabilised though the rest of the year is likely to remain challenging.Adjusted profit before tax in the first half of 2009 eased 4.2% to £25.3m from £26.4m the year before. With amortisation and restructuring costs included profit before tax was £18.5m, versus £25.5m a year earlier.Revenue rose to £227.7m from £216.1m, albeit with the aid of favourable currency fluctuations.Following the sale of North American Plastic Profile and Sheet business net debt was reduced substantially to £118.9m from £182.1m at the end of 2008.The interim dividend has been maintained at 2.70p.