2563
Then , in vitro penetration studies using diffusion cell and pig ear skin were carried out to evaluate the effect of the nanodispersions on the skin penetration of siRNA ; based on these results , the nanodispersions containing MO / OA / PEI / aqueous phase ( 8 : 2 : 5 : 85 , w / w / w / w ) and MO / OA / OAM / aqueous phase ( 8 : 2 : 2 : 88 , w / w / w / w ) were selected .
 Chemical: PEI; Chemical: OAM
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: PEI; Chemical: OAM