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: Mitochondrial injury may be involved in the progression of heart failure caused by adriamycin via the autophagy pathway .
### Output Text:
Mitochondrial injury may be involved in the progression of heart failure caused by <span class="chemical">adriamycin</span> via the autophagy pathway . 