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: An antisialogue was usually unnecessary in operations lasting up to 2 h , glycopyrrolate being the best choice for its lowest psychotropic and chronotropic effects , especially in a hot climate .
### Output Text:
An antisialogue was usually unnecessary in operations lasting up to 2 h , <span class="chemical">glycopyrrolate</span> being the best choice for its lowest psychotropic and chronotropic effects , especially in a hot climate . 