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: It is concluded that anticholinesterases are only partially effective in restoring neuromuscular function in succinylcholine apnoea despite muscle twitch activity typical of phase II block .
### Output Text:
It is concluded that anticholinesterases are only partially effective in restoring neuromuscular function in <span class="chemical">succinylcholine</span> apnoea despite muscle twitch activity typical of phase II block . 