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: Successive transaminase elevations greater than three times the upper limit of normal occurred in 0 . 1 % of women and were dose dependent above the 20 - mg dose .
### Output Text:
Successive transaminase elevations greater than three times the upper limit of normal occurred in 0 . 1 % of women and were dose dependent above the 20 - mg dose . 