3821
Enantioselective hydrolysis of oral racemic methylphenidate ( dl - MPH ) by carboxylesterase 1 ( CES1 ) limits the absolute bioavailability of the pharmacologically active d - MPH isomer to approximately 30 % and that of the inactive l - MPH to only 1 - 2 % .
 Chemical: racemic methylphenidate; Chemical: dl - MPH; Chemical: d - MPH; Chemical: l - MPH
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: racemic methylphenidate; Chemical: dl - MPH; Chemical: d - MPH; Chemical: l - MPH