12304
In vitro studies were performed in the absence of S9 metabolic activation using blood from five healthy volunteers , incubated 72 h with isotretinoin ( 1 . 2 - 20 mu M ) ( i . e . , at concentrations usually achieved in blood with therapeutic doses as well as at higher concentrations ) .
 Chemical: isotretinoin
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: isotretinoin 
Answer:
 Chemical: isotretinoin