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: CONCLUSION : This study showed that spironolactone can reduce potassium requirements and prevent hypokalemia by reducing urinary potassium loss in neutropenic patients on AmB treatment .
### Output Text:
CONCLUSION : This study showed that <span class="chemical">spironolactone</span> can reduce <span class="chemical">potassium</span> requirements and prevent hypokalemia by reducing urinary <span class="chemical">potassium</span> loss in neutropenic patients on <span class="chemical">AmB</span> treatment . 