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 78 - year - old with healed septal necrosis suffered a recurrent myocardial infarction of the anterior wall following the administration of isosorbide dinitrate 5 mg sublingually .
### Output Text:
A 78 - year - old with healed septal necrosis suffered a recurrent myocardial infarction of the anterior wall following the administration of <span class="chemical">isosorbide dinitrate</span> 5 mg sublingually . 