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: Treatment with 150 mg / kg PDTC before and following status epilepticus significantly increased the mortality rate to 100 % .
### Output Text:
Treatment with 150 mg / kg <span class="chemical">PDTC</span> before and following status epilepticus significantly increased the mortality rate to 100 % . 