Bioavailability Study Comparing Tolvaptan Administered Via Nasogastric Tube to Tolvaptan Tablets Swallowed Intact

The purpose of the study is to compare the relative bioavailability and pharmacokinetics of tolvaptan 15 mg tablets administered orally versus tolvaptan via nasogastric (NG) tube in healthy male and female subjects. This study is an open 2-treatment, 2-period, 2-sequence crossover study to compare the relative bioavailability of tolvaptan tablets to tolvaptan given via nasogastric tube in 28 healthy adults. Subjects will be randomized to one of the two treatment sequences; either tolvaptan oral tablets swallowed intact followed by a tablet crushed and administered via nasogastric tube, or the reverse sequence. Serial pharmacokinetic samples will be collected following each tolvaptan administration and safety assessments will be performed. The relative bioavailability of tolvaptan administered via nasogastric tube will be compared to tolvaptan tablets swallowed intact.