Feasibility of the preparation of solvent-free vs solvent liposomes with trans-fatty acids for animal studies

Amrita Dikpati, Karine Greffard, Iwona Rudkowska, Nicolas Bertrand

Endocrinology and Nephrology Unit, CHU de Québec-Laval University Research Center, Québec (QC), Canada; Endocrinology and Nephrology Unit, CHU de Québec-Laval University Research Center, Québec (QC), Canada; Endocrinology and Nephrology Unit, Centre de recherche du CHU de Québec – Université Laval ; Endocrinology and Nephrology Unit, CHU de Québec-Laval University Research Center, Québec (QC), Canada

Objective/Hypothesis: Naturally trans fatty acids (FA) may provide health benefits. However, the low water solubility of FA complexifies studies in animals. Previously, nanovesicles of lecithin were developed using a chloroform-based method. Yet, the solvent used in nanoencapsulation may be toxic to animals. The objective is to examine the feasibility of preparing nanovesicles without solvent. The hypothesis is that 1- the yield will be the equivalent in the solvent and solvent-free preparations and 2- no residual solvent in solvent-free method will be detected.

Methods: Nanovesicles containing either lecithin alone or in combination with trans FA were prepared with two methods. In the lipid-film method, solutions in chloroform were evaporated to form a thin film which was then hydrated. In the solvent-free method, dry powders of lipids were hydrated in ultrapure water at 60°C for six hours. Both hydrated lipid suspensions were extruded on polycarbonate membranes to obtain vesicles with diameters ca. 100 nm. The yield obtained was quantified in the concentrations of phospholipids before and after extrusion. The residual solvent in formulations was measured by gas chromatography.

Results: The yields of the solvent and solvent-free preparations were comparable. The regular lipid-film followed by extrusion method resulted in formulations with residual solvent above acceptable levels (ICH Q3C). In opposition, no solvent was detected in the formulations prepared with the solvent-free method.

Conclusion: Preliminary results suggest the solvent-free preparation method appears a promising way to fabricate vesicles encapsulating FA. Further chemical analysis will be performed to monitor oxidation and lipid content. (

Funding: NSERC)