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: These models may also be useful in developing insights into the pathophysiology of aminoglycoside - induced nephrotoxicity .
### Output Text:
These models may also be useful in developing insights into the pathophysiology of <span class="chemical">aminoglycoside</span> - induced nephrotoxicity . 