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: OBJECTIVE : To evaluate the possible protective effects of misoprostol on renal function in hospitalized elderly patients treated with indomethacin .
### Output Text:
OBJECTIVE : To evaluate the possible protective effects of <span class="chemical">misoprostol</span> on renal function in hospitalized elderly patients treated with <span class="chemical">indomethacin</span> . 