Pharmaceutical co-crystals of quercetin

A composition comprising:

• a) a co-crystal comprising:
• i) Quercetin, a hydrate thereof, a polymorph thereof, a salt thereof, or mixtures thereof;
• and
• ii) at least one first anti-diabetic agent;
• and
• b) a second anti-diabetic agent selected from the group consisting of biguanide drugs;
• sulfonylurea drugs;
• alpha-glucosidase inhibitors;
• thiazolidinedione drugs;
• DPP-IV inhibitors, and mixtures thereof.

A pharmaceutical composition effective for treatment of diabetic cataract, comprising an effective amount of a co-crystal composition;

• said co-crystal composition comprising:
• a) Quercetin, a hydrate thereof, a polymorph thereof, a salt thereof, or mixtures thereof;
• and
• b) at least one first anti-diabetic agent.