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: Safety and adverse effects associated with raloxifene : multiple outcomes of raloxifene evaluation .
### Output Text:
Safety and adverse effects associated with <span class="chemical">raloxifene</span> : multiple outcomes of <span class="chemical">raloxifene</span> evaluation . 