29857
The pharmacokinetic parameters of AUC , t1 / 2 and MRT had no difference between 20 ( R ) - and ( S ) - 25 - OCH3 - PPD , but S - epimer has a lower plasma clearance compared to the R - isomer .
 Chemical: 20 ( R ) - and ( S ) - 25 - OCH3 - 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 ( R ) - and ( S ) - 25 - OCH3 - PPD