GlaxoSmithKline (GSK) saw improved turnover in the fourth quarter as the drugmaker expanded its portfolio and launched new products, but its full year guidance failed to impress. Turnover edged up 2% to £6.9bn in the last three months of 2013, surprising analysts who had expected a turnover of £6.84bn. On a constant exchange rate (CER) basis sales were 5% higher.During the period the group released new products to strengthen businesses in Respiratory, Vaccines, HIV and Oncology. However, core earnings per share (EPS) dropped 7% to 30.1p (Bloomberg consensus: 30.8p) in the final three months of 2013, due to the impact of currencies on the translation of overseas results. On a CER basis EPS stood 1% higher.For the full year core turnover was flat at £26.5bn and EPS rose 1% to 112.2p as sales came under pressure in China, where the company is under investigation for bribery."GSK's trading performance in 2013 was in line with our guidance, despite some unexpected challenges and reflected the improving balance of our sales base," the group said."We are committed to investing behind continuing growth in our important Emerging Markets business. sales in the region were up 5% for the year and 11% in the fourth quarter, excluding the impact of the ongoing investigation by the Chinese authorities."Looking ahead the group expects 2014 EPS growth of 4 to 8% and a 2% rise in turnover.Management also indicated that 2014 share repurchases would be in a range of between £1-2bn.Weaker than expected guidance for sales and EPSAnalysts at Jefferies pointed out that revenues came in 1% ahead of analysts´ estimates while the company´s EPS was bang in line with those same analysts´ calculations.The firms full year 2014 guidance for sales growth, however, at +2% in constant currency terms, was lower than that which the market had been expecting, of approximately 6%. Likewise, the company´s expectations for Core CER EPS of between 4-8% was weaker than expected (consensus: 11%).The size of next year´s stock repurchase programme was in line with the broker´s forecasts. Shares rose 2.51% to 1,592.50p at 12:38 on Wednesday.RD