18798
The aim of this study was to investigate whether the 1 - point , 4 - h postdose ( R ) - omeprazole hydroxylation index ( HI ) of racemic omeprazole reflects the three CYP2C19 genotype groups in Japanese individuals .
 ( R ) - omeprazole, racemic omeprazole
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 ( R ) - omeprazole, racemic omeprazole