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: Bilateral intrastriatal injections of isoniazid did not augment seizures produced by pilocarpine , 200 mg / kg .
### Output Text:
Bilateral intrastriatal injections of <span class="chemical">isoniazid</span> did not augment seizures produced by <span class="chemical">pilocarpine</span> , 200 mg / kg . 