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: In contrast , dosages of Mipafox ( less than or equal to 5 mg / kg ) which inhibited mean NTE activity in spinal cord less than or equal to 61 % and brain less than or equal to 60 % produced this degree of cord damage in only 9 % of the animals .
### Output Text:
In contrast , dosages of <span class="chemical">Mipafox</span> ( less than or equal to 5 mg / kg ) which inhibited mean NTE activity in spinal cord less than or equal to 61 % and brain less than or equal to 60 % produced this degree of cord damage in only 9 % of the animals . 