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: Our results suggest that the neuromuscular dysfunction after prednisolone is dose - dependent , and derives primarily from muscle atrophy and derives less so from changes in AChR expression .
### Output Text:
Our results suggest that the neuromuscular dysfunction after <span class="chemical">prednisolone</span> is dose - dependent , and derives primarily from muscle atrophy and derives less so from changes in AChR expression . 