22222
Penetration of the outer skin layers was followed by rapid dissolution of the PAA binder on contact with the interstitial fluid of the epidermis , implanting the microparticles or solid polymer microneedles in the tissue , which were retained following patch removal .
 Chemical: PAA
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: PAA 
Answer:
 Chemical: PAA