Background: The purpose of this study was to evaluate the effects of monovalent and divalent cations on the stability of a fat emulsion (Lipovenoes MCT) in total nutrient admixtures (TNAs) by testing the percentage of fat residing in globules >5 µm (PFAT5) values.
Methods: TNAs with different combinations of glucose (5% and 10%), amino acids (3.35 and 4.5 g/100 mL), Na+/K+ (100/39 mmol/L), Mg2+ (3.4 and 2.7 mmol/L), and fat emulsion (2.4%) were tested in triplicate at room temperature. The pH, mean droplet size (MDS), and PFAT5 were assessed at 0, 6, 12, 24, 36, and 48 h.
Results: In all seven groups, the TNA globule distribution was uniform, the pH value fluctuated in the range of 5.93-6.06, and the MDS met the limit of the United States Pharmacopeia (USP) within 48 h. The PFAT5 value of the control group 0 without electrolytes was the lowest; group 1 added monovalent ions of 139 mmol/L was significantly higher (P<0.05) but without exceed the USP limit after 48 h. Groups 2 and 3 added Mg2+ 3.4 and 2.7 mmol/L respectively, based on group 1. Group 4 increased the amino acid concentration from 3.35% to 4.5% based on group 2, and group 5 reduced the glucose concentration from 10% to 5% based on group 4. Group 6 removed monovalent ions and retained only Mg2+ based on group 5. The PFAT5 values of group 2, 3, 4, and 5 exceeded the limit after 6 h and group 6 after 12 h. There was no statistical difference between group 2 and 4 (P>0.05) or between group 4 and 5 (P>0.05).
Conclusions: When the concentration of glucose is 10-25% and the amino acid is 2.5-4.5%, The addition of monovalent ions affects the stability of fat emulsion in TNAs, however when the concentrations of Na+ ≤100 mmol/L and K+ ≤39 mmol/L, the PFAT5 value will not exceed the USP limit within 24 h. Mg2+ has a significant effect, the PFAT5 value will exceed the USP limit after 6 h when the concentration ≥2.7 mmol/L, which may cause potential safety hazards.
Keywords: PFAT5; Total nutrient admixtures (TNAs); magnesium ion; monovalent ions; stability of Lipovenoes MCT.