28540
Ovx mice were replaced with vehicle ( sesame oil ) or 17 beta - estradiol ( E2 ) for 2 days or 30 min prior to a cocaine challenge to investigate the time course of E2 ' s effects .
 Chemical: 17 beta - estradiol; Chemical: cocaine
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: 17 beta - estradiol, cocaine 
Answer:
 Chemical: 17 beta - estradiol; Chemical: cocaine