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: Glibenclamide - sensitive hypotension produced by helodermin assessed in the rat .
### Output Text:
<span class="chemical">Glibenclamide</span> - sensitive hypotension produced by <span class="chemical">helodermin</span> assessed in the rat . 