Injection force and dose accuracy of FlexTouch for the delivery of a new basal insulin

The aim of the paper is to determine the dose accuracy and injection force of FlexTouch (FT) filled with insulin degludec 100 U/ml, insulin degludec 200 U/ml and insulin degludec/insulin aspart 100 U/ml, SoloStar (SS) filled with insulin glargine 100 U/ml and KwikPen (KP) filled with insulin lispro mix 75/25 100 U/ml.

Dose accuracy was measured at minimum, midpoint and maximum doses (FT 1, 2, 40, 80 and 160 U; SS 1, 40 and 80 U; KP 1, 30 and 60 U). Injection force was measured during the injection of the maximum dose.

All doses delivered from FT were within ISO limits (ISO 11608-1:2012) for degludec 100 U/ml, degludec 200 U/ml and degludec/aspart 100 U/ml, and the pens delivered insulin accurately and consistently at all doses tested. Similarly, all tested doses from KP filled with insulin lispro mix 75/25 100 U/ml were within ISO limits, while some doses from SS filled with insulin glargine 100 U/ml were outside ISO limits. FT had a significantly lower injection force than SS and KP (p < 0.05).

FT filled with insulin degludec and insulin degludec/insulin aspart, delivered insulin accurately and consistently within ISO limitations at all doses tested; similarly, KP delivered insulin within ISO limitations at all doses tested and SS delivered most doses within ISO limitations. The significantly lower injection force of FT compared to SS and KP is an important feature that has the potential to make the injection process easier for people with diabetes.