The physical stability of two emulsions compounded as part of a total nutrient admixture (TNA) was studied in lipids packaged in either glass or plastic containers.Methods
Five weight-based adult TNA formulations that were designed to meet the full nutritional needs of adults with body weights between 40 and 80 kg were studied. Triplicate preparations of each TNA were assessed over 30 hours at room temperature by applying currently proposed United States Pharmacopeia (USP) criteria for mean droplet diameter, large-diameter tail, and globule-size distribution (GSD) for lipid injectable emulsions. In accordance with conditions set forth in USP chapter 729, the higher levels of volume-weighted percent of fat exceeding 5 μm (PFAT5) should not exceed 0.05% of the total lipid concentration.Results
Significant differences were noted among TNA admixtures based on whether the lipid emulsion product was manufactured in glass or plastic. The plastic-contained TNAs failed the proposed USP methods for large-diameter fat globules in all formulations from the outset, and 60% had significant growth in large-diameter fat globules over time. In contrast, glass-contained TNAs were stable throughout and in all cases would have passed proposed USP limits.Conclusion
Certain lipid injectable emulsions packaged in plastic containers have baseline abnormal GSD profiles compared with those packaged in glass containers. When used to compound TNAs, the abnormal profile worsens and produces less stable TNAs than those compounded with lipid injectable emulsions packaged in glass containers.