Della Santina was an associate of the Bajoran criminal Ibudan.

According to a personal calendar file, Ibudan had a lunch meeting with Della Santina on a Bajoran transport on stardate 46383. This file, along with others, was reviewed by Odo when he was conducting an investigation into the murder of Ibudan. (DS9: "A Man Alone")

This character was only mentioned in writing.
Della Santina was named after Star Trek: Deep Space Nine unit production manager Robert della Santina. (Star Trek: Deep Space Nine Companion, p. 20)