In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: There was no difference in the risk of cardiac events between VNR and other drugs [ odds ratio : 0 . 92 , 95 % CI ( 0 . 54 ; 1 . 55 ) ] .
### Output Text:
There was no difference in the risk of cardiac events between <span class="chemical">VNR</span> and other drugs [ odds ratio : 0 . 92 , 95 % CI ( 0 . 54 ; 1 . 55 ) ] . 