21398
Comparing to free DOX , the DOX - conjugated SPIO nanocomposites showed better antitumor effect under magnetic field .
 Chemical: DOX; Chemical: DOX
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: DOX, DOX 
Answer:
 Chemical: DOX; Chemical: DOX