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: The tic - like symptoms resolved completely after we reduced the dose of amisulpride down to 800 mg per day .
### Output Text:
The tic - like symptoms resolved completely after we reduced the dose of <span class="chemical">amisulpride</span> down to 800 mg per day . 