Background: Inappropriate resuspension of NPH insulin resulted in inaccurate dose of insulin, however those studies estimated the amount of insulin based on the cloudiness of insulin, which did not correctly reflex the amount of insulin.

Objective: To study the effect of inappropriate resuspension of premixed insulin pen on the amount of dispensed insulin which was directly determined using a more accurate Ultra-High performance Liquid Chromatography (UHPLC) technique.

Methods: The premixed 70/30 autopen was used in this study. Four methods of insulin resuspension were evaluated (n=5, for each method), i.e., upright position without resuspension (upright), horizontal position without resuspension (horizon), resuspension by tipping over 5x (5x), and 20x (20x, control). 30 unit of insulin from 1st injection of each pen were collected. Then, 30 units of insulin in each pen were discarded every 20 minutes for 8 times, each pen were kept in the initial resuspension method between each injection, and the last 30 unit of insulin in each pen were collected. Collected insulin were analyzed by UHPLC.

Results: Table showed the UHPLC results.

Conclusions: Inappropriate insulin pen resuspension or the lack thereof have significantly affect the amount of dispensed insulin by 3-6%, and this resulted in inaccurate dose of insulin throughout the used of that pen.


B. Dechates: None. S. Junnu: None. T. Kongmalai: None. C. Srisawat: None. A. Sriwijitkamol: None.

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