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: Given the progressive deterioration of the symptoms and of the laboratory values , despite adequate medical treatment , a decision was made to introduce haemodialytical therapy in order to remove the drug and therapy reduce the nephrotoxicity .
### Output Text:
Given the progressive deterioration of the symptoms and of the laboratory values , despite adequate medical treatment , a decision was made to introduce haemodialytical therapy in order to remove the drug and therapy reduce the nephrotoxicity . 