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: Two studies evaluated quetiapine ( up to 800 mg / day ) in combination with a mood stabilizer ( lithium or divalproex , QTP + Li / DVP ) ( n = 196 ) compared to placebo and mood stabilizer ( PBO + Li / DVP ) ( n = 203 ) .
### Output Text:
Two studies evaluated <span class="chemical">quetiapine</span> ( up to 800 mg / day ) in combination with a mood stabilizer ( <span class="chemical">lithium</span> or <span class="chemical">divalproex</span> , <span class="chemical">QTP</span> + <span class="chemical">Li</span> / <span class="chemical">DVP</span> ) ( n = 196 ) compared to placebo and mood stabilizer ( PBO + <span class="chemical">Li</span> / <span class="chemical">DVP</span> ) ( n = 203 ) . 