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: We conclude that the systemic toxicity of levobupivacaine is intermediate between that of ropivacaine and bupivacaine when administered at the same rate and that ropivacaine - induced cardiac arrest appears to be more susceptible to treatment than that induced by bupivacaine or levobupivacaine .
### Output Text:
We conclude that the systemic toxicity of <span class="chemical">levobupivacaine</span> is intermediate between that of <span class="chemical">ropivacaine</span> and <span class="chemical">bupivacaine</span> when administered at the same rate and that <span class="chemical">ropivacaine</span> - induced cardiac arrest appears to be more susceptible to treatment than that induced by <span class="chemical">bupivacaine</span> or <span class="chemical">levobupivacaine</span> . 