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: CONCLUSION : We conclude that pre - treatment with propofol in intralipid , compared with propofol in medialipid or saline , delayed the onset of bupivacaine - induced cardiotoxic effects as well as reduced plasma bupivacaine levels .
### Output Text:
CONCLUSION : We conclude that pre - treatment with <span class="chemical">propofol</span> in intralipid , compared with <span class="chemical">propofol</span> in medialipid or saline , delayed the onset of <span class="chemical">bupivacaine</span> - induced cardiotoxic effects as well as reduced plasma <span class="chemical">bupivacaine</span> levels . 