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: Muscle strength , contractures , functional ability and pulmonary function were tested at baseline , and 6 and 12 months after treatment with mazindol ( 3 mg / d ) or placebo .
### Output Text:
Muscle strength , contractures , functional ability and pulmonary function were tested at baseline , and 6 and 12 months after treatment with <span class="chemical">mazindol</span> ( 3 mg / d ) or placebo . 