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: CONCLUSION : Tolterodine was well tolerated and its effects improved the quality of life in Thai women with OAB .
### Output Text:
CONCLUSION : <span class="chemical">Tolterodine</span> was well tolerated and its effects improved the quality of life in Thai women with OAB . 