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: We report the case of a 62 - year - old man who was administered sodium valproate ( VPA ) and who subsequently developed the syndrome of inappropriate secretion of antidiuretic hormone ( SIADH ) .
### Output Text:
We report the case of a 62 - year - old man who was administered <span class="chemical">sodium valproate</span> ( <span class="chemical">VPA</span> ) and who subsequently developed the syndrome of inappropriate secretion of antidiuretic hormone ( SIADH ) . 