Objective: To determine in vitro free ion concentration in three standard artificial enteral feeding formulas following the addition of ion exchange resins.
Method: Three standard types of AEF were chosen: Osmolite HN, Nutrison Standard and Isosource Standard. The ion exchange resins used were: Sodium Polystyrene Sulfonate and Calcium Polystyrene Sulfonate. 100 ml of AEF were mixed in a beaker with 1.5 g or 3 g of ion exchange resins for 48 hours at 37 masculineC. Subsequently, the samples were precipitated and the supernatant obtained was used for determining the concentrations of calcium, magnesium, sodium and potassium ions.
Results: The addition of Sodium Polystyrene Sulfonate to different types of enteral feeding formulas reduced the concentrations of potassium, calcium and magnesium ions by 70%. 78.2%, and 77.6% in the case of Osmolite HN; by 72.3%, 69.2% and 63.5% in the case of Nutrison Standard, and by 78.3%, 80.5% and 74.5% in the case of Isosource Standard. In contrast, the addition of Calcium Polystyrene Sulfonate reduced the concentration of potassium and magnesium by 50.5% and 55.5% in the case of Osmolite HN; by 49.8% and 43% in the case of Nutrison Standard and by 42.6% and 37.7% in the case of Isosource Standard.
Conclusions: The addition of ion exchange resins to different types of enteral feeding formulas, allows the in vitro free ion content of these to be reduced.