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: After the administration of nifekalant hydrochloride , sustained VT was terminated .
### Output Text:
After the administration of <span class="chemical">nifekalant hydrochloride</span> , sustained VT was terminated . 