Profoundly improved photostability of dimetronidazole by cocrystallization

Dimetronidazole (DMZ), an veterinary antibiotic, exhibits poor photostability with only 80.38% potency remaining after exposure to illuminance of 4500 lux for 7 days. The photodegradation is accompanied by obvious color change. A 1 : 1 cocrystal of DMZ with saccharine exhibited profoundly improved photostability with 98.95% of DMZ remaining after 7 days under the same light exposure. Thus, this new cocrystal can be used to develop more stable drug products of DMZ.