Tocopherol and tocotrienol homologs in parenteral lipid emulsions

Abstract

Parenteral lipid emulsions, which are made of oils from plant and fish sources, contain different types of tocopherols and tocotrienols (vitamin E homologs). The amount and types of vitamin E homologs in various lipid emulsions vary considerably and are not completely known. The objective of this analysis was to develop a quantitative method to determine levels of all vitamin E homologs in various lipid emulsions. An HPLC system was used to measure vitamin E homologs using a Pinnacle DB Silica normal phase column and an isocratic, n-hexane:1,4 dioxane (98:2) mobile phase. An optimized protocol was used to report vitamin E homolog concentrations in soybean oil-based (Intralipid®, Ivelip®, Lipofundin® N, Liposyn® III, and Liposyn® II), medium- and long-chain fatty acid-based (Lipofundin®, MCT and Structolipid®), olive oil-based (ClinOleic®), and fish oil-based (Omegaven®) and mixture of these oils-based (SMOFlipid®, Lipidem®) commercial parenteral lipid emulsions. Total content of all vitamin E homologs varied greatly between different emulsions, ranging from 57.9 to 383.9 µg/mL. Tocopherols (α, β, γ, δ) were the predominant vitamin E homologs for all emulsions, with tocotrienol content < 0.3%. In all of the soybean emulsions, except for Lipofundin® N, the predominant vitamin E homolog was γ-tocopherol, which ranged from 57–156 µg/mL. ClinOleic® predominantly contained α-tocopherol (32 µg/mL), whereas α-tocopherol content in Omegaven® was higher than most of the other lipid emulsions (230 µg/mL).Practical applicationsThe information on the types and quantity of vitamin E homologs in various lipid emulsions will be extremely useful to physicians and healthcare personnel in selecting appropriate lipid emulsions that are exclusively used in patients with inadequate gastrointestinal function, including hospitalized and critically ill patients. Some emulsions may require vitamin E supplementation in order to meet minimal human requirements.

Tocopherols and Tocotrienols in Common and Emerging Dietary Sources: Occurrence, Applications, and Health Benefits

“…Essential fatty acids are among the nutrients delivered using parenteral nutrition. To understand the potential biological effects of tocols, Xu et al [79] evaluated the identities and quantities of tocopherols and tocotrienols in commercial parenteral lipid emulsions containing medium-chain triacylglycerols, soybean, olive, and fish oils, as well as their mixtures. The contents of tocopherols varied among different samples, whereas the contribution of tocotrienols was minimal or non-existent.…”

Supplemental Parenteral Vitamin E Into Conventional Soybean Lipid Emulsion Does Not Prevent Parenteral Nutrition–Associated Liver Disease in Full‐Term Neonatal Piglets

“…Vitamin E is added to lipid emulsions to reduce the risk of such peroxidation and potentially can also provide increased antioxidant delivery, which may benefit the patient, protecting host cellular membranes from lipid peroxidation 6 . Conventional soybean oil–based lipid emulsions (eg, Intralipid; Fresenius Kabi, Bad Homburg, Germany) contain relatively low amounts of vitamin E. In contrast, the third‐generation lipid emulsions, containing fish oil, have substantially higher α‐tocopherol, the most active antioxidant form of vitamin E, with content in the range of 8–11 times that of the conventional lipid 7 . Therefore, it is unclear if the benefit of treating PNALD that has been observed with fish oil–based emulsions is due to the PUFA content directly or to the added vitamin E. Recent data from preterm piglets suggest that vitamin E may be the main beneficial factor 8 .…”

Impact of SMOFLipid on Pulmonary Alveolar Development in Newborn Guinea Pigs

“…For instance, the high level of vitamin E in SMOF may be questionable. The mean concentration of α‐tocopherol in SMOF is 165 mg/L, whereas it is 21 mg/L in IL . A baseline level of free radicals or oxidants are required for the activation of specific transcription factors, such as Nrf2, that favor transcription of genes encoding for antioxidant enzymes of which those for synthesis of glutathione .…”