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: CPT ( 8 - cyclopentyltheophylline ) - - A1 receptor antagonist , did not show any influence in this test .
### Output Text:
<span class="chemical">CPT</span> ( <span class="chemical">8 - cyclopentyltheophylline</span> ) - - A1 receptor antagonist , did not show any influence in this test . 