Electron Microscopy for the Stability Assessment of Parenteral Nutrition Admixtures: Focus on Precipitation.

(1) Background: parenteral nutrition (PN) is indispensable for patients unable to receive oral or enteral feeding. However, the complexity of PN solutions presents challenges regarding stability and compatibility. Precipitation reactions may occur. The most frequent is the formation of calcium phosphate (Ca-P). The different factors influencing these reactions must be considered to ensure patient safety. (2) Methods: eight paediatric PN solutions were prepared, following standard protocols. Samples were stored at room temperature and in a refrigerator. Electron microscopy, coupled with energy dispersive X-ray spectroscopy (EDS), was employed. Precipitates were analysed for composition and morphology. (3) Results: precipitates were observed in all samples, even at day 0. Crystalline structures, predominantly composed of calcium or magnesium, sometimes associated with chlorine or phosphorus, were detected. Additionally, amorphous precipitates, contained heterogeneous compositions, including unexpected elements, were identified. (4) Conclusions: various precipitates, primarily calcium- or magnesium-based, can form in PN solutions, although it is not expected that they can form under the real conditions of use. Calcium oxalate precipitation has been characterised, but the use of organic calcium and phosphate salts appears to mitigate calcium phosphate precipitation. Electron microscopy provides interesting results on NP precipitation, but sample preparation may present technical limitations that affect the interpretation of the results.

Physicochemical Stability of Hospital Parenteral Nutrition Solutions: Effect of Changes in Composition and Storage Protocol.

(1) Background: Parenteral nutrition (PN) is a technique used for the administration of nutrients to patients for whom traditional routes cannot be used. It is performed using solutions with extremely complex compositions, which can give rise to a large number of interactions. These interactions can impact their stability and put the patient's life at risk. The aim of this study is to determine how changes in composition and storage protocol affect the stability of NP solutions. (2) Methods: Twenty-three samples were prepared according to routine clinical practice, with modifications to the concentration of some components. The samples were stored at room temperature (RT) and refrigerated (4 °C). Measurements of the droplet diameter, pH, density and viscosity were performed for both storage protocols on days 1, 3, 10 and 14. (3) Results: The samples with the lowest concentration of lipids (PN13-17) and proteins (PN18-22) showed a larger droplet diameter than the rest of the samples throughout the experiments. The USP limits were exceeded for some of the measurements of these sample groups. The pH density and viscosity remained relatively constant under the conditions studied. (4) Conclusions: The PN samples were considered stable and safe for administration under real-world conditions, but the samples with the lowest concentrations of lipids and proteins showed a tendency towards emulsion instability.

Evaluation of the Stability of Newborn Hospital Parenteral Nutrition Solutions.

(1) Background: parenteral nutrition (PN) solutions are an extremely complex mixture. It is composed of a multitude of chemical elements that can give rise to a large number of interactions that condition its stability and safety. The aim of this study was to evaluate the stability of PN solutions for preterm infants. (2) Methods: eight samples were prepared according to the protocol for prescribing PN in preterm infants. Samples PN1-PN7 had the normal progression of macronutrients and standard amounts of micronutrients for a 1 kg preterm infant. The PN8 sample had a high concentration of electrolytes, with the idea of forcing stability limits. Samples were stored both at room temperature and under refrigeration. Measurements of globule size, pH, density, and viscosity were performed in both storage protocols on different days after processing. (3) Results: the changes in the composition of the samples did not affect the evolution of the stability at the different measurement times and temperatures. Viscosity was affected by the compositional changes made in the PN samples, but no alterations due to time or temperature were observed. Density and pH remained stable, without significant changes due to time, storage temperature, or different composition. (4) Conclusion: all samples remained stable during the study period and did not undergo significant alterations due to compositional changes or different experimental conditions.