3. Taking drugs that alter the environment of the gastrointestinal，especially alter the gastrointestinal pH，within 30 days before the first dose. Such as Proton pump inhibitors：thiophene, omeprazole, lansoprazole, esomeprazole, etc . and H2 antagonist ranitidine：cimetidine, famotidine, etc .and antacids hydrogen carbonate Sodium, magnesium oxide, aluminum hydroxide, magnesium trisilicate, etc .and gastric mucosal protective agent：sucralfate，and so on.