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: Eosinophilic myocarditis has been reported with an incidence of 2 . 4 % to 7 . 2 % in explanted hearts and may be related to multidrug therapy .
### Output Text:
Eosinophilic myocarditis has been reported with an incidence of 2 . 4 % to 7 . 2 % in explanted hearts and may be related to multidrug therapy . 