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: In another session , tropicamide ( 20 microL , 0 . 01 % ) was administered to both eyes , followed 23 minutes later by the application of pilocarpine ( 20 microL , 0 . 1 % ) to one eye and placebo to the other .
### Output Text:
In another session , <span class="chemical">tropicamide</span> ( 20 microL , 0 . 01 % ) was administered to both eyes , followed 23 minutes later by the application of <span class="chemical">pilocarpine</span> ( 20 microL , 0 . 1 % ) to one eye and placebo to the other . 