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 : In humans , the intracoronary infusion of cocaine sufficient in amount to achieve a high drug concentration in coronary sinus blood causes a deterioration of LV systolic and diastolic performance .
### Output Text:
CONCLUSIONS : In humans , the intracoronary infusion of <span class="chemical">cocaine</span> sufficient in amount to achieve a high drug concentration in coronary sinus blood causes a deterioration of LV systolic and diastolic performance . 