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: A 3 - year - old girl had behavioral deterioration , with hyperkinesis , irritability , and sleeping difficulties after the therapeutic administration of isoniazid .
### Output Text:
A 3 - year - old girl had behavioral deterioration , with hyperkinesis , irritability , and sleeping difficulties after the therapeutic administration of <span class="chemical">isoniazid</span> . 