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: A 77 - y - old patient developed weakness of extremities , legs paralysis , dysarthria and tremor 1 h after ingestion of 200 mg ketoconazole for the first time in his life .
### Output Text:
A 77 - y - old patient developed weakness of extremities , legs paralysis , dysarthria and tremor 1 h after ingestion of 200 mg <span class="chemical">ketoconazole</span> for the first time in his life . 