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: MATERIALS AND METHODS : Two different schedules of CBDCA administration ( 10 mg / kg and 15 mg / kg i . p . twice a week for nine times ) were evaluated in Wistar rats .
### Output Text:
MATERIALS AND METHODS : Two different schedules of <span class="chemical">CBDCA</span> administration ( 10 mg / kg and 15 mg / kg i . p . twice a week for nine times ) were evaluated in Wistar rats . 