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 therapeutic potential of the anticocaine antibody GNC92H2 was examined using a model of cocaine overdose .
### Output Text:
The therapeutic potential of the anticocaine antibody <span class="chemical">GNC92H2</span> was examined using a model of cocaine overdose . 