16650
Blood and urinary concentrations of IR3535 ( (R) ) and its only metabolite , IR3535 ( (R) ) - free acid , were determined over time .
 IR3535, IR3535
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 IR3535, IR3535