21695
3 - ( 4 , 5 - Dimethylthiazol - 2 - yl ) - 2 , 5 - diphenyl tetrazolium ( MTT ) assay was performed to assess cytotoxicity .
 Chemical: 3 - ( 4 , 5 - Dimethylthiazol - 2 - yl ) - 2 , 5 - diphenyl tetrazolium; Chemical: MTT
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: 3 - ( 4 , 5 - Dimethylthiazol - 2 - yl ) - 2 , 5 - diphenyl tetrazolium, MTT 
Answer:
 Chemical: 3 - ( 4 , 5 - Dimethylthiazol - 2 - yl ) - 2 , 5 - diphenyl tetrazolium; Chemical: MTT