Abstract
The safe clinical use and physical stability of a total nutrient admixture (TNA) system containing a soybean oil emulsion (Intralipid) has been reported. A study was conducted to compare the physical stability of four admixtures which were divided into two groups based upon the ratios (1:1:1 and 2:1:1) of amino acids (8.5%), dextrose (70%), and fat emulsion (20%). The fat component in each group contained either a new soy bean fat emulsion, Soyacal, or Intralipid. The quantities of all electrolytes, trace elements and vitamin additives were the same. All solutions were stored at 4°C for 28 days and then held at ambient temperature for 5 days for a total 33-day study period. Each admixture was serially analyzed on days 0, 1, 2, 3, 5, 7, 14, 21, 28, 29, 30, 31, 32, and 33. Examination of gross visual appearance and determinations of pH were performed. Osmolality was measured by means of freezing point depression (Advanced Digimatic Osmometer, Advanced Instruments, Inc., Needham Heights, MA). A Brook-haven particle analyzer was used to measure lipid particle size and particle size distribution. Electron and light microscopy were used to verify maximum particle size and distribution on days 0, 7, 14, 21, 28, and 29. The type of lipid emulsion used did not affect the pH or osmolality of the admixtures. Admixtures prepared with the 2:1:1 ratio had slightly higher pH (0.07) and lower osmolality (350 mOsm/kg). The range of mean diameters for the admixtures prepared with Soyacal and Intralipid were 0.283 to 0.310 μm and 0.314 to 0.351 μm, respectively. Based upon particle size distribution, 95% of all particles were less than 0.395 and 0.392 μm (Soyacal) and 0.444 and 0.439 μm (Intralipid). The largest particle observed in the admixture was 8.75 μm. Our data indicate that the physical stability of a TNA system prepared with Soyacal 20% or Intralipid 20% are similar. (Journal of Parenteral and Enteral Nutrition 10:381-387, 1986)
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