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: CONCLUSIONS : Alprazolam caused side - effects and adverse effects during treatment but many patients were willing to accept these .
### Output Text:
CONCLUSIONS : <span class="chemical">Alprazolam</span> caused side - effects and adverse effects during treatment but many patients were willing to accept these . 