The study drug which is an inhaled bronchodilator (lung airway relaxant)has been given to both healthy volunteers and to COPD patients before. This study will assess a new formulation of GSK573719. Many drugs are known to deteriorate over time. To make the study medicine less likely to deteriorate in its container, it is mixed with an inactive substance that helps to to maintain the quality of the study medicine. Previous studies have looked at GSK573719 with another inactive substance called Cellobiose Octaacetate (COA). This study will be looking at a new formulation of GSK573719 using Magnesium Stearate (MgSt) as the inactive substance. MgSt itself is not a medicine but is approved as a food ingredient and has also has been approved to be used in a number of marketed medical inhalers. The purpose of this study is to assess the safety and tolerability of compound GSK573719 with Magnesium Stearate for once-daily treatment of COPD(Chronic Obstructive Pulmonary Disease). This drug will be given to 2 groups of 12 people for 7 days. Group 1 will receive 250mcg or placebo and group 2 will receive 1000mcg or placebo. Group 2 will not be dosed until at least 6 people have completed dosing in group 1 without any significant safety concerns. The following safety measures will be assessed including: ECGs, heart rate, blood pressure, blood samples for safety labs, lung function and 24 hour monitoring of the heart. We will also take blood and urine samples to measure medication levels in the body.