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: Patients given prilocaine were more likely to develop hearing loss ( 10 out of 22 ) than those given bupivacaine ( 4 out of 22 ) ( P < 0 . 05 ) .
### Output Text:
Patients given <span class="chemical">prilocaine</span> were more likely to develop hearing loss ( 10 out of 22 ) than those given <span class="chemical">bupivacaine</span> ( 4 out of 22 ) ( P < 0 . 05 ) . 