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: We report a case of a 31 year old female who required admission to the Intensive Care Unit for ventilation and full supportive therapy , following ingestion of 13 . 5g bupropion .
### Output Text:
We report a case of a 31 year old female who required admission to the Intensive Care Unit for ventilation and full supportive therapy , following ingestion of 13 . 5g <span class="chemical">bupropion</span> . 