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: A 27 - year old African woman with history of regular chloroquine ingestion presented with progressive deterioration of vision , easy fatiguability , dyspnoea , dizziness progressing to syncopal attacks .
### Output Text:
A 27 - year old African woman with history of regular <span class="chemical">chloroquine</span> ingestion presented with progressive deterioration of vision , easy fatiguability , dyspnoea , dizziness progressing to syncopal attacks . 