title: A prefilled insulin pen with a novel injection mechanism and a lower injection force than other prefilled insulin pens.
abstract: BACKGROUND
  FlexTouch(®) (Novo Nordisk A/S, Bagsvaerd, Denmark) is a new prefilled insulin pen for people with diabetes, with a novel injection mechanism and no push-button extension at any dose setting. This study compared the injection force of FlexTouch with that of SoloStar(®) (sanofi-aventis, Paris, France) and KwikPen(®) (Eli Lilly & Co., Indianapolis, IN).
  
  
  METHODS
  Injection force was measured with the manufacturers' recommended needle attached to each pen (NovoFine(®) [Novo Nordisk] 32-gauge tip extra thin wall 6 mm needle for FlexTouch and BD [Franklin Lakes, NJ] MicroFine™ 31-gauge 5 mm needle for SoloStar and KwikPen) during injection of the maximum dose (60 IU for KwikPen and 80 IU for FlexTouch and SoloStar). Injection was performed at three different constant push-button speeds.
  
  
  RESULTS
  FlexTouch had a significantly (P<0.0001) lower injection force than SoloStar and KwikPen at all injection speeds. The mean±SD injection force of FlexTouch was 5.1±0.5 N. At 4, 6, and 8 mm/s push-button speeds, the injection force of SoloStar was 13.5±2.1, 19.1±1.9, and 26.9±2.4 N, respectively, and the injection force of KwikPen was 14.5±1.9, 20.9±1.4, and 28.2±1.4 N, respectively.
  
  
  CONCLUSIONS
  The injection mechanism of FlexTouch means that insulin injection is driven by a torque spring and not the thumb pressure of the user. This results in a 62-82% lower injection force with FlexTouch than other prefilled insulin pens.
authors.affiliation: Novo Nordisk A/S, Hillerød, Denmark .
authors.forename: Hans
authors.initials: H
authors.lastname: Hemmingsen
authors.forename: Marcus
authors.initials: M
authors.lastname: Niemeyer
authors.forename: Marianne Rye
authors.initials: MR
authors.lastname: Hansen
authors.forename: Ditlef
authors.initials: D
authors.lastname: Bucher
authors.forename: Niels Bjerrum
authors.initials: NB
authors.lastname: Thomsen
mesh_terms: D003920:Diabetes Mellitus / Q000188:drug therapy*; D016503:Drug Delivery Systems / Q000295:instrumentation*; D007328:Insulin / Q000008:administration & dosage*
chemical_list: D007328:Insulin