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: Although both formulations had similar pharmacokinetic and pharmacodynamic profiles the new formulation is not suitable for clinical use due to the high incidence of thrombophlebitis produced .
### Output Text:
Although both formulations had similar pharmacokinetic and pharmacodynamic profiles the new formulation is not suitable for clinical use due to the high incidence of thrombophlebitis produced . 