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: All patients received succinylcholine 1 . 5 mg / kg at 2 minutes after the precurarization , and were assessed the incidence and severity of fasciculations , while myalgia was assessed at 24 hours after surgery .
### Output Text:
All patients received <span class="chemical">succinylcholine</span> 1 . 5 mg / kg at 2 minutes after the precurarization , and were assessed the incidence and severity of fasciculations , while myalgia was assessed at 24 hours after surgery . 