Helen F. Giles-Gee, the first African American and first female president of the University of the Sciences, has resigned after only two and a half years at the helm, the university announced Tuesday.

Her resignation comes as the University City campus is preparing to close down for winter break and is effective Dec. 31, the university said.

Giles-Gee is not available for comment, a university spokesman said.

"At this time and after serious reflection, I have decided to leave University of the Sciences. I am honored to have served as president and will hold this University dear in my heart," Giles-Gee said in a prepared statement.

Board Chairman Marvin Samson, CEO of Samson Medical Technologies in Cherry Hill, will step in as interim president, the university said.

Giles-Gee - who has degrees from both the University of Pennsylvania and Rutgers — came to the University of the Sciences as its 22nd president from Keene State College in New Hampshire where she had been president for a longer tenure, 2005 through 2012. She has spent 30-plus years in higher education at a variety of institutions and roles, including as provost of Rowan University and an administrator at Cheyney University. She also was associate vice chancellor for academic affairs at the University of Maryland, where she handled issues ranging from articulation agreements with community colleges to space planning.

Giles-Gee was the first African American and first female leader in the university's 192 year-history. When she was introduced as the new leader in 2012, some women in the audience cried.

The school a short time later hired Heidi M. Anderson, an African American female, as provost. It meant that a university almost exclusively led by white males for two centuries - and one with a focus on pharmacy, science, and health-care careers - had gained a decidedly different leadership look.

The first college of pharmacy in North America, the school sits on 36 acres and serves about 2,800 undergraduate and graduate students.