NovoMix® 30 FlexPen. Each box contains 5 prefilled pens, with each pen containing 3 ml of NovoMix 30 at a concentration of 100 U/ml. NovoMix 30 is an insulin aspart biphasic formulation (30% soluble insulin aspart and 70% protamine crystallised insulin aspart), commonly used for the treatment of diabetes mellitus. The FlexPen is a pre-filled, disposable pen device designed for convenient self-injection. This medication should only be used as directed by a healthcare professional.