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: Current options of treatment include oral anticholinergic drugs , the topical application of anticholinergics or aluminum chloride , and the injection of botulinum toxin .
### Output Text:
Current options of treatment include oral anticholinergic drugs , the topical application of anticholinergics or <span class="chemical">aluminum chloride</span> , and the injection of botulinum toxin . 