20759
The initial effort led to the first - generation PARP1 inhibitor 26 bearing a terminal phthalazin - 1 ( 2H ) - one framework and showing remarkably high PARP1 inhibitory activity ( 0 . 31 nM ) but only moderate potency in the cell .
 Chemical: phthalazin - 1 ( 2H ) - one
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: phthalazin - 1 ( 2H ) - one