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: CONCLUSIONS : DBP , but not SBP , reduction was associated with neurological worsening after the intravenous administration of high - dose nimodipine after acute stroke .
### Output Text:
CONCLUSIONS : DBP , but not SBP , reduction was associated with neurological worsening after the intravenous administration of high - dose <span class="chemical">nimodipine</span> after acute stroke . 