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: To determine if the addition of a buffering solution to adjust the pH of lidocaine into the physiologic range would reduce pain during injection , we performed a blinded randomized study in patients undergoing cardiac catheterization .
### Output Text:
To determine if the addition of a buffering solution to adjust the pH of <span class="chemical">lidocaine</span> into the physiologic range would reduce pain during injection , we performed a blinded randomized study in patients undergoing cardiac catheterization . 