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: METHODS : Seventeen subjects who were genotyped as CYP2D6 extensive metabolizers were enrolled in this randomized , open - label , crossover study to receive a single oral dose of desipramine ( 50 mg ) on two separate occasions , once alone and once after multiple doses of cinacalcet ( 90 mg for 7 days ) .
### Output Text:
METHODS : Seventeen subjects who were genotyped as CYP2D6 extensive metabolizers were enrolled in this randomized , open - label , crossover study to receive a single oral dose of <span class="chemical">desipramine</span> ( 50 mg ) on two separate occasions , once alone and once after multiple doses of <span class="chemical">cinacalcet</span> ( 90 mg for 7 days ) . 