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: This case represents the most thoroughly investigated case of amiodarone - induced myxoedema coma with a history significant for subclinical thyroid disease .
### Output Text:
This case represents the most thoroughly investigated case of <span class="chemical">amiodarone</span> - induced myxoedema coma with a history significant for subclinical thyroid disease . 