Marta Walczykiewicz of Poland and Osypenko-Radomska made the best start, taking the early advantage in the race.
However, Carrington came into contention after the 50m mark, easing into a lead over her rivals.
The 23-year-old held on into the final stretch as Douchev-Janics went into third place.
Great Britain's Jess Walker finished in seventh place with a time of 46.161.
Carrington crossed the line at 44.638s to win the gold medal.