Comparison of the activity of Rapitard and Actraphane insulins

This study examined the activity of two intermediate acting premixed insulins, Rapitard and Actraphane, in non diabetic individuals using the euglycaemic clamp technique. Rapitard, a mixture of 25% soluble porcine insulin and 75% bovine insulin crystals was compared to porcine Actraphane, a mixture of 30% soluble and 70% isophane insulins. Glucose requirements and serum insulin levels were monitored over a 12 h period. The mean (+/- SEM) total glucose requirements were higher following administration of Actraphane (246.7 +/- 37.2 g) compared to Rapitard (188.7 +/- 15.4 g) but this difference did not reach statistical significance. Following injection of Actraphane significantly higher glucose infusion rates for the half hour periods from 240, 270, 300, 330 and 420 min and serum insulins at 180, 210, 240, 270, 300, 330, 360 and 480 min were observed compared to Rapitard. These differences are likely to be of clinical relevance and should be considered when changing a diabetic subject from Rapitard to Actraphane insulins.