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: The finding of an augmented risk of pacemaker insertion in elderly women receiving amiodarone requires further investigation .
### Output Text:
The finding of an augmented risk of pacemaker insertion in elderly women receiving <span class="chemical">amiodarone</span> requires further investigation . 