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: These observations indicate that initial hopes that sulindac may not be associated with the adverse renal effects of other NSAID are probably not justified .
### Output Text:
These observations indicate that initial hopes that <span class="chemical">sulindac</span> may not be associated with the adverse renal effects of other NSAID are probably not justified . 