29858
The active metabolite 20 ( S ) - 25 - OH - PPD showed significantly higher AUC , MRT and a longer half - life than that of 20 ( R ) - 25 - OH - PPD .
 Chemical: 20 ( S ) - 25 - OH - PPD; Chemical: 20 ( R ) - 25 - OH - PPD
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: 20 ( S ) - 25 - OH - PPD; Chemical: 20 ( R ) - 25 - OH - PPD