2449
The patient ' s ophthalmological symptoms improved rapidly 3 weeks after discontinuation of pegylated IFN alpha - 2b and ribavirin .
 Chemical: pegylated IFN alpha - 2b; Chemical: ribavirin
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: pegylated IFN alpha - 2b, ribavirin 
Answer:
 Chemical: pegylated IFN alpha - 2b; Chemical: ribavirin