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: All dogs ( n = 6 ) randomly received orally dronedarone ( 10 and 30 mg / kg ) , amiodarone ( 10 and 30 mg / kg ) , and placebo twice daily for 7 days , with a 3 - week washout between consecutive treatments .
### Output Text:
All dogs ( n = 6 ) randomly received orally <span class="chemical">dronedarone</span> ( 10 and 30 mg / kg ) , <span class="chemical">amiodarone</span> ( 10 and 30 mg / kg ) , and placebo twice daily for 7 days , with a 3 - week washout between consecutive treatments . 