Evaluation of injection force of three insulin delivery pens.
OBJECTIVE
Reduced injection force is among the modifications to the Next Generation FlexPen (NGFP). This force was compared with two other prefilled pens: SoloStar (SS) and KwikPen (KP).


METHODS
The injection force of the pens was measured, with either a BD Micro-Fine 31G thin-wall needle, or a NovoFine 32G Tip extra thin wall needle attached. Pens of each type were tested with both needles, during injection of 20 U insulin, at speeds 3.3, 5 and 8.3 mm/s.


RESULTS
NGFP had a significantly (p < 0.05) lower mean injection force than SS or KP, at all injection speeds, with both needles. Injection forces (mean +/- s.d.) with NGFP and the BD Micro-Fine() 31G thin-wall needle were: 8.1 +/- 0.7, 10.7 +/- 1.4 and 15.6 +/- 0.9 N at the three speeds, respectively. For SS, the corresponding values were: 9.2 +/- 0.5, 13.3 +/- 0.8 and 20.7 +/- 2.4 N. For KP they were: 12.5 +/- 1.6, 16.9 +/- 1.2 and 24.5 +/- 2.6 N. Attached to the NovoFine 32G Tip extra thin wall needle, the NGFP injection forces were: 5.7 +/- 0.4, 8.2 +/- 0.7 and 12.7 +/- 0.5 N; with SS were: 6.7 +/- 0.3, 10.4 +/- 2.1 and 16.3 +/- 1.1 N; and with KP were: 9.1 +/- 1.3, 13.1 +/- 0.8 and 21.6 +/- 2.0 N. The injection force with NGFP was 12 - 25% lower compared with SS and 35 - 41% lower compared with KP.


CONCLUSIONS
This study shows that NGFP has a significantly lower injection force than SS or KP.
Asakura
T
T
Department of Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1 Higashizima, Akiha-ku, Niigata, 956-8603, Japan. asa-mac@m7.dion.ne.jp
Seino
H
H
Kageyama
M
M
Yohkoh
N
N
D016503:Drug Delivery Systems / Q000009:adverse effects / Q000295:instrumentation* / Q000592:standards; D004867:Equipment Design / Q000295:instrumentation / Q000592:standards; D004869:Equipment Safety / Q000592:standards; D007279:Injections, Subcutaneous / Q000009:adverse effects / Q000295:instrumentation / Q000592:standards; D007328:Insulin / Q000008:administration & dosage*; D007332:Insulin Infusion Systems / Q000009:adverse effects / Q000592:standards; D012646:Self Administration
D007328:Insulin