7898
In the present study , we report a new acid - degradable poly ( ketal amidoamine ) ( PKAA ) as a siRNA carrier , which has high delivery efficiency and low cytotoxicity .
 Chemical: poly ( ketal amidoamine ); Chemical: PKAA
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: poly ( ketal amidoamine ); Chemical: PKAA