Experience of compounding total parenteral nutrition admixtures for preterm infants in a hospital pharmacy: evidence of calcium and phosphate compatibility problem.

OBJECTIVE: Parenterally fed preterm newborn infants require large amounts of calcium and phosphate in a low volume of solution. The lower the volume of solution, the higher is the possibility of precipitation of calcium hydrogen phosphate (CaHPO4). Precipitation could cause respiratory distress and pulmonary embolism, and the use of organic salts of calcium and phosphorus may reduce the likelihood of this problem. To date, no previous work on the stability of solutions with organic salts has been published in the literature. This study aims to evaluate the visible precipitation of calcium and phosphorus in total parenteral nutrition solutions.
METHODS: 20 parenteral nutrition solutions were aseptically prepared in a laminar airflow hood in a clean room. The solutions are intended to facilitate precipitation, with the amino acid ratio below the standard concentration and other parameters also modulated to promote the precipitation of CaHPO4. The solutions contained dextrose, amino acids, calcium gluconate and fructose 1,6-bisphosphate. We did not use lipid emulsion so that we could see all precipitations.
RESULTS: No visible precipitation was observed during 4 weeks of observation at 25°C. The only observed event was the change in colour of the solution, which became yellow, maybe because of a Maillard reaction.
CONCLUSIONS: This study evaluated the compatibility of organic calcium and phosphorus in order to prevent the precipitation of CaHPO4 when preparing total parenteral nutrition solutions. The fact that no precipitation was observed is very significant as it indicates the compatibility of the ions, even though no instrumental analysis was performed.