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: However , ketone bodies were consistently present in urine and several lethalities occurred during multiple dosing of captopril in SHR .
### Output Text:
However , <span class="chemical">ketone</span> bodies were consistently present in urine and several lethalities occurred during multiple dosing of <span class="chemical">captopril</span> in SHR . 