This is a single-center, randomized, two part, open-label, crossover study in healthy adult subjects. Part A will evaluate the relative bioavailability of two new tablet formulations compared to the current tablet formulation of GSK1349572 at 50 mg administered as single doses each comprising of two 25 mg tablets. Pharmacokinetic samples from Part A will be analyzed and, if at least one of the new formulations meets appropriate criteria and is selected, Part B will be a single-sequence design conducted to evaluate food effect of the selected new tablet formulation at one dose level. A subset of subjects enrolled in Part A will continue in Part B. Safety evaluations and serial PK samples will be collected during each treatment period. A follow-up visit will occur 7-28 days after the last dose of study drug.