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: Azimilide , however , significantly prolonged APD and QT interval at concentrations from 0 . 1 to 10 micromol / L but shortened them at 30 micromol / L .
### Output Text:
<span class="chemical">Azimilide</span> , however , significantly prolonged APD and QT interval at concentrations from 0 . 1 to 10 micromol / L but shortened them at 30 micromol / L . 