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: Corresponding figures during HCTZ therapy 100 mg daily were 1 . 4 + / - 0 . 1 , 3 . 6 + / - 0 . 7 and 5 . 7 4 / - 0 . 8 , respectively .
### Output Text:
Corresponding figures during <span class="chemical">HCTZ</span> therapy 100 mg daily were 1 . 4 + / - 0 . 1 , 3 . 6 + / - 0 . 7 and 5 . 7 4 / - 0 . 8 , respectively . 