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: The cause of hyperkalemia was considered to be several doses of spiranolactone , an aldosterone antagonist , in addition to the long - term intake of ramipril , an ACE inhibitor .
### Output Text:
The cause of hyperkalemia was considered to be several doses of <span class="chemical">spiranolactone</span> , an <span class="chemical">aldosterone</span> antagonist , in addition to the long - term intake of <span class="chemical">ramipril</span> , an ACE inhibitor . 