(W0930-11-61) Quantitative and Qualitative Analysis of Lipids and Cholesterol Derivatives in SMOF Lipids 20% Intravenous Lipid Emulsion

Purpose: SMOF lipids^® 20% is an intravenous lipid emulsion (ILEs) used for parenteral nutrition to provide essential fatty acids as energy for the patients who have difficulty absorbing nutrition through digestive tract. Although these emulsions are made from natural sources like fish oil, medium chain triglycerides, soybean oil and olive oil, the composition of these lipids can vary based on sources and manufacturing processes. Moreover, these lipids are susceptible to hydrolytic degradation leading to the generation of various degradation products that can alter the expected composition of the formulation, potentially affecting patients. Given the pivotal role of lipid composition in parenteral nutrition ILEs, accurate quantification of lipid constituents and identification of possible lipid degradation products, as well as cholesterol oxidation products, are necessary for a comprehensive evaluation of the formulation in post-market studies. In this study, we developed a set of UHPLC-QTOF-ESI/APCI methods to identify free fatty acids, triglycerides, cholesterol derivatives, and phospholipids present in SMOF lipids^® 20%.

Methods: In this study, a series of UHPLC-HRMS (QTOF) methods was developed to detect and quantify free fatty acids, triglycerides, cholesterol derivatives, and phospholipids found in SMOF lipids® 20%. We utilized various reversed-phase UHPLC techniques for lipid component separation, and detection was carried out using ESI/QTOF (electron spray ionization) MS and APCI/QTOF (atmospheric pressure chemical ionization) techniques. To identify the separated lipids and cholesterols, we utilized Premier Biosoft SimLipid® software, and external sources such as Lipid Maps. Based on availability, the identified lipids were cross verified with their standards. The composition of these identified lipids was determined either quantitatively or semi-quantitatively, utilizing commercially available lipid standards.

Results: The examination of SMOF lipids® 20% demonstrated a wide array of lipids and cholesterol derivatives at varying quantities, ranging from grams to milligrams. Identified compounds included 14 free fatty acids (Figure 1), 11 cholesterol and cholesterol derivatives (Figure 2), 23 triglycerides (TG, comprising 7 medium-chain triglycerides (MCTs) and 17 long-chain triglycerides), 12 lyso-phospholipids, and 51 phospholipids. Oleic acid and linoleic acid emerged as the predominant free fatty acids in SMOF lipids, while cholesterol and campesterol were the dominant cholesterol derivatives. The most prevalent medium chain triglyceride in SMOF lipids was TG (8:0/8:0/10:0), while TG (18:1/18:1/18:1) stood out as the most abundant long-chain triglyceride.

Conclusion: We have effectively developed a series of LCMS-HRMS methods designed for the separation, identification, and quantification of various lipid components in the SMOF lipids^® 20%, including free fatty acids, triglycerides, cholesterol, cholesterol derivatives, and phospholipids. This analytical approach can be extended to assess other ILE products, providing a means to determine their actual lipid composition and identify degradation products.


Figure 1: Ion chromatogram of identified free fatty acids.


Figure 2: Ion chromatogram of identified cholesterol derivatives.