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: This pilot trial aimed to evaluate the role of glutamate supplementation for preventing PAC - induced peripheral neuropathy in a randomized , placebo - controlled , double - blinded clinical and electro - diagnostic study .
### Output Text:
This pilot trial aimed to evaluate the role of <span class="chemical">glutamate</span> supplementation for preventing <span class="chemical">PAC</span> - induced peripheral neuropathy in a randomized , placebo - controlled , double - blinded clinical and electro - diagnostic study . 