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: The topical application of a glycopyrrolate pad appeared to be safe , efficacious , well tolerated , and a convenient method of treatment for moderate to severe symptoms of gustatory hyperhidrosis in post transthoracic endoscopic sympathectomy or sympathicotomy patients , with few side effects .
### Output Text:
The topical application of a <span class="chemical">glycopyrrolate</span> pad appeared to be safe , efficacious , well tolerated , and a convenient method of treatment for moderate to severe symptoms of gustatory hyperhidrosis in post transthoracic endoscopic sympathectomy or sympathicotomy patients , with few side effects . 