21085
This compound also displayed stronger in vivo antinociceptive activity after iv administration when compared to morphine in the tail - flick test , which indicates that this analogue was able to cross the blood - brain barrier .
 Chemical: morphine
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: morphine 
Answer:
 Chemical: morphine