Healthy male and female (not gender stratified) subjects aged 18-55 years inclusive - healthy subjects are defined as individuals who are free from clinically significant illness or disease as determined by their medical history, physical examination, laboratory studies, ECGs, and other tests. A subject with clinical abnormality or laboratory parameters outside the reference range for this age group may be included only if the Investigator and the GSK Medical Monitor considers that the findings will not introduce additional risk factors and will not interfere with the study procedures.