title: Force requirements and insulin delivery profiles of four injection devices.
abstract: BACKGROUND
  Injection force requirements for four insulin pen-type injection devices were evaluated using the AGS-IkNG Autograph force measurement device (Shimadzu Corp., Kyoto, Japan).
  
  
  RESULTS
  Compared with the Humulin Pen (the Japanese brand name is Humacart kit; the same device as the Humalog Pen; Eli Lilly, Indianapolis, IN), HumaPen Ergo (Eli Lilly), and NovoPen 3 (Novo Nordisk A/S, Bagsvaerd, Denmark), the InnoLet(Novo Nordisk) required the lowest injection force to both initiate piston movement and commence insulin delivery and required the lowest overall force throughout delivery. InnoLet and NovoPen 3 showed the most even load-displacement curves, suggesting a smoother delivery of insulin during injection. In contrast, the Humulin Pen and HumaPen Ergo demonstrated marked fluctuations in the force required to complete injection.
  
  
  CONCLUSIONS
  These performance characteristics appeared consistent with mechanical features of these insulin delivery devices, and the results highlight the potential importance of careful pen selection for patients with neuromuscular weakness or impaired manual coordination.
authors.affiliation: Department of Pharmacy, Saiseikai Fukuoka General Hospital, 1-3-46 Tenjin, Cho-ku, Fukuoka Prefecture, 810-0001 Fukuoka, Japan. toraishi@saiseikai-hp.chuo.fukuoka.jp
authors.forename: Kenichi
authors.initials: K
authors.lastname: Toraishi
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Yuizono
authors.forename: Noriko
authors.initials: N
authors.lastname: Nakamura
authors.forename: Shino
authors.initials: S
authors.lastname: Kato
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Aoki
authors.forename: Kenji
authors.initials: K
authors.lastname: Ashida
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Sako
mesh_terms: D003920:Diabetes Mellitus / Q000188:drug therapy; D004867:Equipment Design; D006801:Humans; D007279:Injections, Subcutaneous / Q000295:instrumentation* / Q000379:methods* / Q000592:standards; D007328:Insulin / Q000008:administration & dosage* / Q000627:therapeutic use; D013314:Stress, Mechanical
chemical_list: D007328:Insulin