 This study is conducted to determine whether the test product GW483100 10 mg containing montelukast sodium equivalent to 10 mg of montelukast is bioequivalent to the reference montelukast sodium 10 mg tablets innovator product in healthy adult volunteers under fasting conditions. This is an open-label, balanced, randomized, single dose, two-way crossover study, enrolling 32 healthy human subjects to ensure at least 28 subjects complete the study. Each subject enrolled will participate in two treatment periods separated by a washout period of at least 7 days and no more than 14 days between dosing occasions. Total duration in the study for each subject will be approximately 7 weeks from screening to the subjects last visit. 