21371
The aim of the present work was to study in vitro , across isolated bovine sclera , the effect of iontophoresis on the transport of three single stranded oligonucleotides ( ssDNA ) , 12 - , 24 - and 36 - mer , selected as reference compounds in view of a non - invasive drug delivery to the back of the eye .
 None
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:  
Answer:
 None