Human Mixtard insulin is available in various combinations such as 30% neutral insulin with 70% isophane and 50% neutral insulin with 50% isophane. In any event, the quantity of total insulin is either 40 international units per ml or 100 international units per ml. Therefore for 10 units you can use either 0.25 ml of 40 IU/ml preparation or 0.10 ml of 100 IU/ml preparation.