<qa>  What is the purpose of this Phase IV study?This Phase IV study is intended to compare intragastric acid suppression of oral esomeprazole NEXIUM Delayed-Release Capsules with that of oral pantoprazole PROTONIX Delayed Release Tablets , in subjects who continue to require acid-suppressive therapy following a course of intravenous iv pantoprazole PROTONIX I.V. for Injection. 