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: In two of the three deaths probably associated with ketoconazole treatment the drug had been continued after the onset of jaundice and other symptoms of hepatitis .
### Output Text:
In two of the three deaths probably associated with <span class="chemical">ketoconazole</span> treatment the drug had been continued after the onset of jaundice and other symptoms of hepatitis . 