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: Combination of SCH 23390 with sulpiride did not induce catalepsy potentiation .
### Output Text:
Combination of <span class="chemical">SCH 23390</span> with <span class="chemical">sulpiride</span> did not induce catalepsy potentiation . 