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: She had defects in the supratentorial brain including the basal ganglia and the striatum ( multicystic encephalomalacia ) due to severe perinatal hypoxic - ischemic encephalopathy , which was considered to be a possible predisposing factor causing neuroleptic malignant syndrome .
### Output Text:
She had defects in the supratentorial brain including the basal ganglia and the striatum ( multicystic encephalomalacia ) due to severe perinatal hypoxic - ischemic encephalopathy , which was considered to be a possible predisposing factor causing neuroleptic malignant syndrome . 