A HPLC method to monitor the occurrence of lipid peroxidation in intravenous lipid emulsions used in parenteral nutrition using in-line UV and charged aerosol detection

Abstract

Parenteral Nutrition (PN) provides life sustaining support where gastrointestinal nutrition is inadequate due to disease or prematurity. Intravenous lipid emulsions (IVLEs) form a staple part of PN. Whilst the physical stability of IVLE's is relatively well known and quantified, chemical stability is an area where little testing has occurred. We report a new sensitive method for the monitoring of selected triglycerides present within two IVLEs and the detection and quantification of the peroxidation product 4-hydroxynonenal (HNE) using HPLC with in-line UV and charged aerosol detection (CAD). IVLEs used included the soy-bean oil based emulsion Intralipid^® 20% and SMOFlipid^® 20% (Fresenius Kabi UK), based on soy-bean, olive, fish oil and medium chain triglycerides. Assay validation gave R² values of ≥0.99 for all selected triglyceride peaks and 4-hydroxynonenal. Inter and intra-day repeatability gave RSD values < 7.2% for CAD detection, achieving a precise and repeatable method. HNE was confirmed through internal standardisation of the HPLC method. Selected triglycerides were identified using ESI-MS with MicroTOF. This novel method permits the chemical stability of IVLEs to be quantified and monitored in respect to lipid peroxidation during storage prior to delivery to the patient, ensuring the optimal safety of IVLEs in a clinical setting.

Keywords: Fatty acid/oxidation; Intravenous lipid emulsions; Lipid peroxidation; Lipids; Lipids/emulsions; Methods/HPLC; Non-aqueous reversed phase high performance liquid chromatography; Oxidised lipids; Parenteral nutrition; Quantitation; Triglycerides.