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: Hydrocortisone acetate ( 50 mg ) was given orally every 6 hours for 24 hours after a 5 - day fixed - salt diet ( 150 mmol / d ) .
### Output Text:
<span class="chemical">Hydrocortisone acetate</span> ( 50 mg ) was given orally every 6 hours for 24 hours after a 5 - day fixed - salt diet ( 150 mmol / d ) . 