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: Primary efficacy end points were reduction in clinical systolic BP ( SBP ) / diastolic BP ( DBP ) from baseline to study end and number of responders ( ie , patients who achieved target SBP / DBP < 130 / < 80 mm Hg ) at end of study .
### Output Text:
Primary efficacy end points were reduction in clinical systolic BP ( SBP ) / diastolic BP ( DBP ) from baseline to study end and number of responders ( ie , patients who achieved target SBP / DBP < 130 / < 80 mm Hg ) at end of study . 