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 dose of hyperbaric 5 % lignocaine administered ranged from 60 to 120 mg .
### Output Text:
The dose of hyperbaric 5 % <span class="chemical">lignocaine</span> administered ranged from 60 to 120 mg . 