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: We describe three patients in whom severe , life - threatening hyperkalemia and renal insufficiency developed after treatment of acute gouty arthritis with indomethacin .
### Output Text:
We describe three patients in whom severe , life - threatening hyperkalemia and renal insufficiency developed after treatment of acute gouty arthritis with <span class="chemical">indomethacin</span> . 