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: Physicians and other healthcare professionals should be aware of this potential adverse effect of tiapride and amisulpride .
### Output Text:
Physicians and other healthcare professionals should be aware of this potential adverse effect of <span class="chemical">tiapride</span> and <span class="chemical">amisulpride</span> . 