Toronto made just two of 20 field goal attempts in the second, while Philadelphia connected on 13 of 18.
"We lost our focus on both ends," DeRozan said. "We couldn't score, couldn't get stops."
The second-quarter meltdown was a new wrinkle for the 1-5 Raptors, who've been working to clean up slow starts.
"We play three quarters and kind of lose it in one, everything we've worked for," Calderon said. "We have to try and do better. We have to play for a full 48 (minutes) or we are not going to be able to beat good teams."
Bargnani scored eight points in the third as the Raptors closed the gap, and Amir Johnson's alley-oop at the buzzer cut it to 69-62 heading into the fourth.
DeRozan cut it to six with a free throw to start the final quarter, but back-to-back 3-pointers from Wright restored Philadelphia's double-digit lead, and ensured the Sixers' third straight victory in Toronto.
Calderon started at point guard for the Raptors in place of Kyle Lowry (right ankle), while Alan Anderson started for Landry Fields (right wrist). Anderson, however, sprained his left foot late in the third and had to be carried off. He did not return.
The 76ers played without center Kwame Brown (left calf) and guard Jason Richardson (left ankle).
NOTES: Evan Turner led the 76ers with 12 rebounds. ... Lowry, Toronto's leading scorer, left in the first half of Tuesday's loss at Oklahoma City and has not played since. Fields, who has been sore for several weeks, saw a hand specialist Friday and is scheduled to see another doctor next week. ... Linas Kleiza returned to Toronto's lineup after missing the past four games for personal reasons. ... The Raptors wore camouflage jerseys in honor of Sunday's Remembrance Day holiday. ... The 76ers are 4-0 when leading after three quarters. ... Philadelphia has won three straight in Toronto.