16309
From the equilibrium of lactone hydrolysis in rat plasma in vitro , the k obs was - 0 . 0176 min ( - 1 ) and t 1 / 2 was 39 . 38 min .
 Chemical: lactone
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: lactone