4542
At the highest effective doses , PG - 9 did not produce any collateral symptoms as revealed by the Irwin test , and it did not modify spontaneous motility and inspection activity , as revealed by the hole - board test .
 PG - 9
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Disease, Chemical 
Text: {0} 
Answer:
 PG - 9