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: Thirty minutes after 99mTc - glucarate administration the standardised heart uptake value S ( h ) UV was 4 . 7 in infarcted rat heart which is six times more than in normal rats .
### Output Text:
Thirty minutes after <span class="chemical">99mTc - glucarate</span> administration the standardised heart uptake value S ( h ) UV was 4 . 7 in infarcted rat heart which is six times more than in normal rats . 