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: Nicotine - induced hyperactivity was blocked by the selective D1 antagonist SCH 23390 , the selective D2 antagonist raclopride and the D1 / D2 antagonist fluphenazine .
### Output Text:
<span class="chemical">Nicotine</span> - induced hyperactivity was blocked by the selective D1 antagonist <span class="chemical">SCH 23390</span> , the selective D2 antagonist <span class="chemical">raclopride</span> and the D1 / D2 antagonist <span class="chemical">fluphenazine</span> . 