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 effect of a widely used organic solvent , polyethylene glycol 400 ( PEG 400 ) , on the toxic action of an acute or chronic treatment with adriamycin ( ADR ) was evaluated in mice .
### Output Text:
The effect of a widely used organic solvent , <span class="chemical">polyethylene glycol 400</span> ( <span class="chemical">PEG 400</span> ) , on the toxic action of an acute or chronic treatment with <span class="chemical">adriamycin</span> ( <span class="chemical">ADR</span> ) was evaluated in mice . 