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: Treatment with propanolol administered intravenously ( 1 - 5 mg ) produced increases in supine and upright blood pressure in 4 of the 5 individuals with rises ranging from 11 / 6 to 22 / 11 mmHg .
### Output Text:
Treatment with <span class="chemical">propanolol</span> administered intravenously ( 1 - 5 mg ) produced increases in supine and upright blood pressure in 4 of the 5 individuals with rises ranging from 11 / 6 to 22 / 11 mmHg . 