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: ROC curve analysis revealed that unresponsiveness to verapamil defined as PRL < 7 % , discriminated anatomical or functional stalk effect ( sensitivity : 74 % , specificity : 73 % , AUC : 0 . 855 + / - 0 . 04 , P < 0 . 001 , CI : 0 . 768 - 0 . 942 ) associated with pseudoprolactinoma or risperidone - induced hyperprolactinemia , respectively .
### Output Text:
ROC curve analysis revealed that unresponsiveness to <span class="chemical">verapamil</span> defined as PRL < 7 % , discriminated anatomical or functional stalk effect ( sensitivity : 74 % , specificity : 73 % , AUC : 0 . 855 + / - 0 . 04 , P < 0 . 001 , CI : 0 . 768 - 0 . 942 ) associated with pseudoprolactinoma or <span class="chemical">risperidone</span> - induced hyperprolactinemia , respectively . 