2455
Metformin also protected the kidney from histological damage 6 days after gentamicin administration .
 Chemical: Metformin; Chemical: gentamicin
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Disease, Chemical 
Text: {0} 
 Entities: Metformin, gentamicin 
Answer:
 Chemical: Metformin; Chemical: gentamicin