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 woman with coronary artery disease who developed a markedly prolonged QT interval and torsades de pointes ( TdP ) after taking ketoconazole for treatment of fungal infection .
### Output Text:
We report a woman with coronary artery disease who developed a markedly prolonged QT interval and torsades de pointes ( TdP ) after taking <span class="chemical">ketoconazole</span> for treatment of fungal infection . 