After yesterday's aimless trading session, London's blue-chips are seeking direction again today, with City traders tipping the FTSE 100 will open down 14 points from yesterday's close of 5,365. Pharmaceuticals giant AstraZeneca said full year core earnings per share (EPS) are set to be in the lower half of its guidance range as a result of impairment charges taken following setbacks in two of its drug development programmes: Olaparib and TC-5214.Bus and train group National Express remains firmly on track to deliver revenue and profit growth in 2011 in every one of its divisions. Trading across the group remains strong, the company said, and full year profit is expected to be in line with the board's previous expectations.Advertising titan WPP, led by Sir Martin Sorrell, has acquired a 49% stake in Chinese peer Nanjing Yindu Advertising and Commerco Co for an undisclosed sum.--jh