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: When tested in a multivariate regression analysis , tranexamic acid was a strong independent predictor of seizures ( OR 14 . 3 , 95 % CI 5 . 5 - 36 . 7 ; p < 0 . 001 ) .
### Output Text:
When tested in a multivariate regression analysis , <span class="chemical">tranexamic acid</span> was a strong independent predictor of seizures ( OR 14 . 3 , 95 % CI 5 . 5 - 36 . 7 ; p < 0 . 001 ) . 