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: The first group of patients was administered isotonic sodium chloride ; the second group was administered a solution that of 5 % dextrose and sodium bicarbonate , while the third group was administered isotonic sodium chloride before and after the contrast injection .
### Output Text:
The first group of patients was administered isotonic <span class="chemical">sodium chloride</span> ; the second group was administered a solution that of 5 % <span class="chemical">dextrose</span> and <span class="chemical">sodium bicarbonate</span> , while the third group was administered isotonic <span class="chemical">sodium chloride</span> before and after the <span class="chemical">contrast</span> injection . 