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 the group that received 1 . 0 mg doxorubicin / kg , the serum albumin level decreased from 33 . 6 + / - 4 . 1 to 1 . 5 + / - 0 . 5 g / liter .
### Output Text:
In the group that received 1 . 0 mg <span class="chemical">doxorubicin</span> / kg , the serum albumin level decreased from 33 . 6 + / - 4 . 1 to 1 . 5 + / - 0 . 5 g / liter . 