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: Comparison of i . v . glycopyrrolate and atropine in the prevention of bradycardia and arrhythmias following repeated doses of suxamethonium in children .
### Output Text:
Comparison of i . v . <span class="chemical">glycopyrrolate</span> and <span class="chemical">atropine</span> in the prevention of bradycardia and arrhythmias following repeated doses of <span class="chemical">suxamethonium</span> in children . 