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 performed a phase II trial of paclitaxel 175 mg / m2 over 3 hours on day I followed by folinic acid 300 mg over 1 hour before 5 - fluorouracil 350 mg / m2 on days 1 to 3 every 28 days ( TFL ) in women with metastatic breast cancer .
### Output Text:
We performed a phase II trial of <span class="chemical">paclitaxel</span> 175 mg / m2 over 3 hours on day I followed by <span class="chemical">folinic acid</span> 300 mg over 1 hour before <span class="chemical">5 - fluorouracil</span> 350 mg / m2 on days 1 to 3 every 28 days ( TFL ) in women with metastatic breast cancer . 