11234
Increasing the dose of theophylline up to 15 . 45 mu mol / kg / day caused no further stepping improvement since it was only 41 +/- 6 % of the maximal effect produced by caffeine at the dose of 5 . 15 mu mol / kg / day .
 Chemical: theophylline; Chemical: caffeine
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: theophylline; Chemical: caffeine