[Measurement of insulin in multilayer bags for parenteral nutrition]

Introduction: it is common to add rapid-acting insulin to parenteral nutrition (NP) bags for the management of hyperglycemia. However, insulin can be adsorbed in NP bags due to electrostatic interactions. Objective: to determine the influence of the presence of lipids and of insulin concentration in NP bags on the adsorption of insulin in these bags, as well as its stability for 5 days. Method: seven NP bags were prepared with the same volume and with a similar composition except for the presence of lipids and micronutrients, and insulin concentration. Insulin was determined by electrochemiluminescent immunoassay. Samples of 2 mL were taken after preparation and on day 5. Results: on day 1, the mean loss of insulin was 15.26 % (± 7.08) in the bags with lipids and 18.45 % (± 5.67) (p = 0.60) in the bags without lipids. The percentage of insulin lost by day 5 in the PN bags with lipids was 30.13 % (± 4.14), and in the PN bags without lipids it was 44.71 % (± 12.94) (p = 0,052). No correlation was observed between the amount of insulin added to the PN bags and the percentage of insulin lost between day 1 (ρ = -0.407, p = 0.365) or day 5 (ρ = -0.295, p = 0.521). Conclusions: there is an increase in insulin adsorption in NP EVA bags over time. The presence of lipids in the bags decreases adsorption. Further studies are needed to demonstrate the factors associated with insulin adsorption in EVA bags.