5876
The principal biotransformation pathway involved glucuronidation of the glycoside hydroxyl groups to yield three regioisomeric metabolites , M4a , M4b , and M4c ( ~ 39 . 3 % of the dose in urine ) , of which M4c was the major regioisomer ( ~ 31 . 7 % of the dose ) .
 Chemical: hydroxyl
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: hydroxyl