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: This article reports the changes in gallbladder function examined by ultrasonography in 20 Chinese patients with active acromegaly treated with sc injection of the somatostatin analog octreotide in dosages of 300 - 1500 micrograms / day for a mean of 24 . 2 + / - 13 . 9 months .
### Output Text:
This article reports the changes in gallbladder function examined by ultrasonography in 20 Chinese patients with active acromegaly treated with sc injection of the somatostatin analog <span class="chemical">octreotide</span> in dosages of 300 - 1500 micrograms / day for a mean of 24 . 2 + / - 13 . 9 months . 