Stability of intralipid fat emulsion in amino acid solutions

The stability of the fat emulsion Intralipid 20% depends to a great extent on the electric-repulsive forces between the fat particles. The negative charge of the fat particles (zeta-potential) in Intralipid 20% was measured in large bags containing three different commercially available amino acid solutions, two of which had electrolytes. In each case, the electronegativity was not great enough to give the solution adequate stability. When arginine and methionine were added to Intralipid, an increase in pH resulted in more of an electronegative zeta-potential. Varying the concentration of arginine did not affect the zeta-potential the same as changing the pH of the mixture. Thus, a high pH and, to a lesser extent, the quantities of amino acids appear to be important factors in increasing the electrostability of Intralipid.