Relative Bioavailability Study in Healthy Subjects

Inclusion Criteria: * The subject is healthy. * Male or female between 18 and 65 years of age inclusive, at the time of signing the informed consent. * A female is eligible to enter and participate in this study if she is of Non-childbearing potential * Male subjects must agree to use one of the contraception methods listed in the protocol Body weight greater than or equal to 50 kg and body mass index between 18.5-29.9 kg/m2 inclusive. Capable of giving written informed consent * QTcB less than 450 msec; or QTc less than 480 msec in subjects with Bundle Branch Block on Screening ECG. * AST, ALT, alkaline phosphatase and bilirubin less than or equal to 1.5xULN (isolated bilirubin greater than 1.5xULN is acceptable if bilirubin is fractionated and direct bilirubin less than 35%) Exclusion Criteria: * The subject has a positive pre-study drug/alcohol screen. * A positive pre-study Hepatitis B surface antigen or positive Hepatitis C antibody result within 3 months of screening. * Current or chronic history of liver disease, or known hepatic or biliary abnormalities (with the exception of Gilbert's syndrome or asymptomatic gallstones). * A positive test for HIV antibody. * History of regular alcohol consumption within 6 months of the study defined in the protocol. * The subject has participated in a clinical trial and has received an investigational product within the following time period prior to the dosing day in the current study: 30 days, 5 half-lives or twice the duration of the biological effect of the investigational product (whichever is longer). * Exposure to more than four new chemical entities within 12 months prior to the dosing day. * Use of prescription or non-prescription drugs, including vitamins, herbal and dietary supplements (including St John's Wort) within 7 days (or 14 days if the drug is a potential enzyme inducer) or 5 half-lives (whichever is longer) prior to the first dose of study medication, unless in the opinion of the Investigator and GSK Medical Monitor the medication will not interfere with the study procedures or compromise subject safety. * History of sensitivity to any of the study medications, or components thereof or a history of drug or other allergy that, in the opinion of the investigator or GSK Medical Monitor, contraindicates their participation. * Where participation in the study would result in donation of blood or blood products in excess of 500 mL within a 56 day period. * Pregnant females as determined by positive human chorionic gonadotropin test at screening or prior to dosing. * Lactating females. * Subjects who have asthma or a history of asthma within the past 6 months. * History of smoking or history of regular use of tobacco- or nicotine-containing products within 3 months prior to screening. * Consumption of red wine, seville oranges, grapefruit or grapefruit juice, pummelos, satsuma, ugli, tangerine, and tangelo, exotic citrus fruits, grapefruit hybrids or fruit juices from 7 days prior to the first dose of study medication