10967
The studies demonstrated the importance of the H - bond donor on the C20 ' position and revealed the presence of a space surrounding the C20 ' substituent that tolerates a wide variety of substituents , remarkably enhancing potency of vinblastine analogues .
 Chemical: H; Chemical: vinblastine
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: H; Chemical: vinblastine