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: Prilocaine is an amide local anesthetic with a duration of action similar to that of lidocaine .
### Output Text:
<span class="chemical">Prilocaine</span> is an amide local anesthetic with a duration of action similar to that of <span class="chemical">lidocaine</span> . 