Background and Importance Parenteral nutrition (PN) has a complex composition, so interactions between components lead to instability compromising its safety. Large precipitates can cause thromboembolisms and death. Low concentrations of lipids and amino acids and high concentrations of cations correlate with poorer stability (higher risk of precipitate formation).

Aim and Objectives To analyse the stability of PN samples attending to the appearance of precipitates using optical microscopy measurements.

To evaluate the influence of temperature and time on stability.

Material and Methods We studied 5 PN samples (all-in-one). From a baseline formulation (standard macronutrient ratios), we decreased the lipid concentrations from sample 1 to 5. Micronutrients amounts were greater than those recommended, and vitamins (hydrosoluble and lyposolubles) and zinc were also added. 500mL per sample were prepared according to the centre’s protocols. On day 0, a single stock sample was prepared from which 2 aliquots of 250 mL were separated and stored at room temperature (RT) and in a refrigerator (4°C) for 14 days. In order to determine the physical stability of the samples, precipitate formation was assessed using a Fast Read Biosigma® counting camera on a Nikon Eclipse 50i microscope®. Images were taken with a 40X magnification objective. Measurements were taken on the sample on day 1 (4°C) and day 14 (RT and 4°C). Only precipitates larger than 5 microns and with a clearly crystalline form were counted in this analysis. Results are expressed in precipitates per microlitre (according to chamber manufacturer’s recommendations).

Results Precipitates were observed in 4/5 samples. All precipitates corresponded to samples analysed after 14 days of storage at RT, none in those stored in the refrigerator. Figure 1 represents the data obtained and an example of the type of precipitates found.

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Abstract 3PC-008 Figure 1

Conclusion and Relevance Prolonged storage at room temperature clearly influences the appearance of precipitates.

The observed form of the precipitates may correspond to calcium oxalate crystals, formed by the reaction between calcium and vitamin C degradation products.

The importance of the use of filters in the administration of PN is emphasised.

To establish the overall stability of the PN, more complete studies should be carried out, which analyse more stability-dependent processes.

Conflict of Interest No conflict of interest.