BACKGROUND: Common clinical practice for the provision of parenteral nutrition of neonates is to administer the nutrients in separate solutions. The aim of this study was to introduce and examine an alternative way of parenteral feeding for neonates, providing all-in-one parenteral regimes. METHODS: Stability studies were carried out on 2 all-in-one admixtures. Stability assays consisted of the assessment of the admixture's (1) macroscopic aspect, (2) drop size measurement, (3) pH measurement, (4) peroxide value, and (5) alpha-tocopherol concentration. For the measurements, the admixtures were stored at 2 different temperatures, 4 degrees C (storage) and 25 degrees C (compounding), and then analyzed at a starting time, 24 hours, 48 hours, and 7 days after compounding. RESULTS: The 2 all-in-one parenteral admixtures for neonates were shown to be physically stable under analysis conditions, and there were no particles larger than 1 mum. The maximum loss of alpha-tocopherol was approximately 24%. In all-in-one admixtures, lipid peroxide occurred within 24 hours after the addition of the lipid emulsion. CONCLUSIONS: The addition of fat emulsion and fat-soluble vitamins did not alter the physical stability of parenteral admixtures for neonates. Moreover, the admixtures examined were relatively chemically stable for 24 hours, as far as vitamin E is concerned. Lipid peroxidation was the limiting factor for application stability of an all-in-one neonatal parenteral regimen.