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: At a dose of 9 mg / kg , resultant penetration of 5 % was higher than in previous reports , more consistent with inflamed meninges .
### Output Text:
At a dose of 9 mg / kg , resultant penetration of 5 % was higher than in previous reports , more consistent with inflamed meninges . 