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: Amiloride reduced the drinking and urine volume of rats in an acute ( 6 or 12 h ) and a subacute ( 3 days ) experiment .
### Output Text:
<span class="chemical">Amiloride</span> reduced the drinking and urine volume of rats in an acute ( 6 or 12 h ) and a subacute ( 3 days ) experiment . 