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: In a second group , the development of anemia was prevented by rHuEPO ( 1000 IU / kg ) administered s . c . three times / week starting 7 days before carboplatin application .
### Output Text:
In a second group , the development of anemia was prevented by rHuEPO ( 1000 IU / kg ) administered s . c . three times / week starting 7 days before <span class="chemical">carboplatin</span> application . 