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: Relative to desipramine alone , mean AUC and C ( max ) of desipramine increased 3 . 6 - and 1 . 8 - fold when coadministered with cinacalcet .
### Output Text:
Relative to <span class="chemical">desipramine</span> alone , mean AUC and C ( max ) of <span class="chemical">desipramine</span> increased 3 . 6 - and 1 . 8 - fold when coadministered with <span class="chemical">cinacalcet</span> . 