6569
Optimization of HTS hit 1 for NPY Y5 receptor binding affinity , CYP450 inhibition , solubility and metabolic stability led to the identification of some orally available oxygen - linker derivatives for in vivo study .
 Chemical: oxygen
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: oxygen