4664
METHODS : According to a double - blind , randomised , controlled , threefold cross - over design , 18 healthy subjects ( 11 males , 7 females ; mean age 26 years ) received either placebo , 400 mg ibuprofen , or 800 mg ibuprofen .
 Chemical: ibuprofen; Chemical: ibuprofen
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Disease, Chemical 
Text: {0} 
Answer:
 Chemical: ibuprofen; Chemical: ibuprofen