An Open-label, Randomised, Single Dose, Three-Way Crossover, Six Sequence, Pilot Study to Determine the Relative Bioavailability of Montelukast Sodium 5mg From Two Candidate Chewable Tablet Formulations of GW483100 Relative to One 5mg Chewable Tablet of Reference Montelukast Sodium in Healthy Adult Subjects Under Fasting Conditions

This study is designed to estimate the bioavailability of montelukast from the 5 milligrams (mg) montelukast sodium (GW483100) test formulations relative to 5 mg montelukast sodium reference chewable tablets (innovator product). It is an open-label, randomized, single dose, three-way cross over, six sequence study in 18 healthy human subjects. Each subject will participate in all three treatment periods. Subjects will be randomized to one of six sequences and administered one of the three treatments A, B or C in each treatment period, where Treatment A is 5mg chewable tablet of reference 5 mg montelukast sodium reference chewable tablets (innovator product), Treatment B is test formulation 1: 5mg montelukast sodium (GW483100) chewable tablet and Treatment C is test formulation 2: 5mg montelukast sodium (GW483100) chewable tablet. The treatment periods will be separated by a washout period of 7 to 14 days. Total duration in the study for each subject will be approximately 8 weeks from screening to the follow-up visit.