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 case about a female with essential hypertension on drug treatment with amlodipine developed loss of taste sensation .
### Output Text:
We report a case about a female with essential hypertension on drug treatment with <span class="chemical">amlodipine</span> developed loss of taste sensation . 