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: Medications were given four times daily ; the azelastine groups received 0 . 5 , 1 . 0 , or 2 . 0 mg in the morning and evening with placebo in the early and late afternoon ; the chlorpheniramine group received 4 . 0 mg four times daily .
### Output Text:
Medications were given four times daily ; the <span class="chemical">azelastine</span> groups received 0 . 5 , 1 . 0 , or 2 . 0 mg in the morning and evening with placebo in the early and late afternoon ; the <span class="chemical">chlorpheniramine</span> group received 4 . 0 mg four times daily . 