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: Association of DRD2 polymorphisms and chlorpromazine - induced extrapyramidal syndrome in Chinese schizophrenic patients .
### Output Text:
Association of DRD2 polymorphisms and <span class="chemical">chlorpromazine</span> - induced extrapyramidal syndrome in Chinese schizophrenic patients . 