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: Urologists should be aware that this medication can cause metabolic acidosis in patients secondary to inhibition of carbonic anhydrase .
### Output Text:
Urologists should be aware that this medication can cause metabolic acidosis in patients secondary to inhibition of carbonic anhydrase . 