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An Assessment of the Accuracy of NovoPen 1 Delivery After Prolonged Use
Author(s) -
Gordon D.,
Wilson M.,
Paterson K. R.,
Semple C. G.
Publication year - 1990
Publication title -
diabetic medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.474
H-Index - 145
eISSN - 1464-5491
pISSN - 0742-3071
DOI - 10.1111/j.1464-5491.1990.tb01407.x
Subject(s) - medicine , reproducibility , injector , insulin delivery , plunger , insulin pen , surgery , diabetes mellitus , insulin , chromatography , type 1 diabetes , mechanical engineering , materials science , composite material , endocrinology , chemistry , engineering
Forty‐five NovoPen 1 injection devices have been assessed for accuracy of insulin delivery. Twenty‐six pen‐injectors had been returned either because the device had developed structural faults or the patients had experienced unexpected deterioration in diabetic control. Twelve of these pen‐injectors were unusable. The remaining 14 pen‐injectors (‘faulty pen‐injectors’) were assessed by measuring the weight of insulin solution delivered in each of 10 depressions of the plunger and compared with similar measurements from 10 unused pen‐injectors (‘new pen‐injectors’) and 9 pen‐injectors (‘used pen‐injectors’) which had been used uneventfully for > 3 years. New pen‐injectors delivered insulin solution with an accuracy (median error) of 2.8 % and reproducibility (median SD) of 2.0 %. Used pen‐injectors had an accuracy of 2.3 % and reproducibility of 3.5 %. The 14 suspect pen‐injectors (‘faulty pen‐injectors’) demonstrated an accuracy of 2.8 % with reproducibility of 4.0 %. The reduction in reproducibility was due to faults in 4 pen‐injectors, 2 of which consistently delivered less insulin than expected, while a further two pen‐injectors were intermittently inaccurate.