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: The incidence of cardiovascular thrombotic events ( cardiac , cerebrovascular and peripheral vascular , or arterial thrombotic ) was determined by analyzing pooled valdecoxib ( 10 - 80 mg daily ) , nonselective NSAID ( diclofenac 75 mg bid , ibuprofen 800 mg tid , or naproxen 500 mg bid ) and placebo data from 10 randomized osteoarthritis and rheumatoid arthritis trials that were 6 - 52 weeks in duration .
### Output Text:
The incidence of cardiovascular thrombotic events ( cardiac , cerebrovascular and peripheral vascular , or arterial thrombotic ) was determined by analyzing pooled <span class="chemical">valdecoxib</span> ( 10 - 80 mg daily ) , nonselective NSAID ( <span class="chemical">diclofenac</span> 75 mg bid , <span class="chemical">ibuprofen</span> 800 mg tid , or <span class="chemical">naproxen</span> 500 mg bid ) and placebo data from 10 randomized osteoarthritis and rheumatoid arthritis trials that were 6 - 52 weeks in duration . 