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: Administered at the dose of 20 mg . intravesically , CP did not produce any behavioral effects , whereas acrolein at 0 . 5 mg . intravesically induced behavioral modifications identical to those under CP 200 mg . / kg .
### Output Text:
Administered at the dose of 20 mg . intravesically , <span class="chemical">CP</span> did not produce any behavioral effects , whereas <span class="chemical">acrolein</span> at 0 . 5 mg . intravesically induced behavioral modifications identical to those under <span class="chemical">CP</span> 200 mg . / kg . 