Compatibility of Maximum Inorganic and Organic Calcium and Phosphate Content in Neonatal Parenteral Solutions

The purpose of the study was to determine the maximum safe concentration of calcium and phosphate in neonatal parenteral nutrition (PN) solutions when various combinations of inorganic and organic salts are applied. Twelve PN solutions for neonatal use were aseptically prepared. Increasing concentrations of inorganic and organic calcium and phosphate were added to the standard formulas. Each admixture was separately tested according to the following conditions; after mixing, at 37 °C for 24 hr, and the maximum safe combination of calcium and phosphate were stored at 4 °C for 30 days and followed by 24 hr at 37 °C. Visual inspections and microscopic observation of undiluted PN solutions as well as the membrane filter after filtration of the PN solution, pH evaluation, and absorbance were examined. The safe maximum concentration of organic and inorganic calcium and phosphate were proposed individually for each composition of parenteral nutrition solutions. Surprisingly, organic calcium with organic phosphate showed precipitation but over the therapeutic range. The protective effect of amino acid was observed and higher concentrations of calcium and phosphate were free of precipitation. This work is valuable in daily practice as it allows an increase in the limits of calcium and phosphate in PN solutions for infants.