Mixing and storage

Add 2 mL of bacteriostatic water to a 5 mg vial, slowly down the glass, and swirl until clear. That gives 2.5 mg per mL, so 300 mcg is 0.12 mL, or 12 units on a U-100 syringe, and 500 mcg is 20 units. A 10 mg vial with 2 mL gives 5 mg per mL, so 300 mcg is 6 units. Before mixing keep it cold and dark; after mixing keep it in the fridge at 2 to 8 C and use within 28 days.