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: Women were randomly assigned to raloxifene 60 mg / d or 120 mg / d or placebo .
### Output Text:
Women were randomly assigned to <span class="chemical">raloxifene</span> 60 mg / d or 120 mg / d or placebo . 