Stability of Liposyn II fat emulsion in total nutrient admixtures

Compatibility and safety of a safflower oil-soybean oil lipid emulsion (Liposyn II, Abbott) with amino acids and dextrose in total nutrient admixtures (TNAs) were studied. Sixty-two admixtures representing 31 different combinations of fat emulsion, amino acid injection, and dextrose injection were tested. Both 10% and 20% concentrations of the fat emulsion and three concentrations each of amino acid injection and dextrose injection were used; the core admixture components were placed in empty flexible plastic bags in three different sequences: fat, amino acids, dextrose; fat, then dextrose and amino acids simultaneously; and amino acids and dextrose simultaneously, then fat. One of two mixtures of electrolytes and trace metals was added to each sample at the end of mixing. Six samples were tested after one day at 25 degrees C, 35 after two days at 5 degrees C plus one day at 30 degrees C, and 21 after nine days at 5 degrees C plus one day at 25 degrees C. Multivitamin injections were added to each TNA just before the 24-hour room-temperature storage. pH, emulsion particle size, and zeta potential (electrostatic surface charge of lipid particles) were measured after visual inspection of each sample. Amino acids were separated by high-performance liquid chromatography and measured. Dextrose was measured by size-exclusion chromatography. In a controlled study of 24 dogs, six-hour infusions of TNAs containing Liposyn II 20% were administered for 14 days, after which all major organs and tissues were studied microscopically. At all storage times in the compatibility study, all TNAs retained a uniform, milk-like appearance.(ABSTRACT TRUNCATED AT 250 WORDS)