title: Rapid Quantification and Validation of Lipid Concentrations within Liposomes.
abstract: Quantification of the lipid content in liposomal adjuvants for subunit vaccine formulation is of extreme importance, since this concentration impacts both efficacy and stability. In this paper, we outline a high performance liquid chromatography-evaporative light scattering detector (HPLC-ELSD) method that allows for the rapid and simultaneous quantification of lipid concentrations within liposomal systems prepared by three liposomal manufacturing techniques (lipid film hydration, high shear mixing, and microfluidics). The ELSD system was used to quantify four lipids: 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), cholesterol, dimethyldioctadecylammonium (DDA) bromide, and ᴅ-(+)-trehalose 6,6'-dibehenate (TDB). The developed method offers rapidity, high sensitivity, direct linearity, and a good consistency on the responses (R² > 0.993 for the four lipids tested). The corresponding limit of detection (LOD) and limit of quantification (LOQ) were 0.11 and 0.36 mg/mL (DMPC), 0.02 and 0.80 mg/mL (cholesterol), 0.06 and 0.20 mg/mL (DDA), and 0.05 and 0.16 mg/mL (TDB), respectively. HPLC-ELSD was shown to be a rapid and effective method for the quantification of lipids within liposome formulations without the need for lipid extraction processes.
authors.affiliation: Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, UK. carla.roces-rodriguez@strath.ac.uk.
authors.forename: Carla B
authors.initials: CB
authors.lastname: Roces
authors.affiliation: Aston Pharmacy School, School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK. kastnere@aston.ac.uk.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Kastner
authors.affiliation: Aston Pharmacy School, School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK. stonep@aston.ac.uk.
authors.forename: Peter
authors.initials: P
authors.lastname: Stone
authors.affiliation: School of Pharmacy and Pharmaceutical Sciences, Ulster University, Coleraine BT52 1SA, UK. d.lowry@ulster.ac.uk.
authors.forename: Deborah
authors.initials: D
authors.lastname: Lowry
authors.affiliation: Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, UK. yvonne.perrie@strath.ac.uk.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Perrie
keywords: ELSD; HPLC; cholesterol; lipids; liposomes; quantification