25517
We observed concentration - dependent transplacental clearance of metformin in both maternal - to - fetal and fetal - to - maternal directions ; in addition metformin crossed the placenta from the fetal to maternal compartment even against its concentration gradient .
 Chemical: metformin; Chemical: metformin
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: metformin; Chemical: metformin