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: We present a 15 - year - old girl schizophrenic who developed frequent involuntary eye - blinking movements after 5 months of amisulpride treatment ( 1000 mg per day ) .
### Output Text:
We present a 15 - year - old girl schizophrenic who developed frequent involuntary eye - blinking movements after 5 months of <span class="chemical">amisulpride</span> treatment ( 1000 mg per day ) . 