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: The likelihood that bupropion induced hepatotoxicity in our patient was possible , based on the Naranjo probability scale .
### Output Text:
The likelihood that <span class="chemical">bupropion</span> induced hepatotoxicity in our patient was possible , based on the Naranjo probability scale . 