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: Edrophonium 10 mg , given 74 min after succinylcholine , when train - of - four stimulation was characteristic of phase II block , produced partial antagonism which was not sustained .
### Output Text:
<span class="chemical">Edrophonium</span> 10 mg , given 74 min after <span class="chemical">succinylcholine</span> , when train - of - four stimulation was characteristic of phase II block , produced partial antagonism which was not sustained . 