Effect of formulation method and lipid composition on liposome lamellarity

Liposomes are vesicles comprising a phospholipid membrane bilayer around an aqueous core. They are well-established in the fields of drug delivery and diagnostics. To translate formulations from bench to bedside, their structure and morphology must be precisely understood. Specifically, characterising lamellarity (number of bilayers) in vesicle populations is crucial as it influences release kinetics and encapsulation efficiency. We have characterised the effect of formulation method and lipid composition on vesicle lamellarity in phosphocholine vesicles. Here, we propose applying these models to study phospholipid-based vesicles which more closely represent those in pharmaceutical formulations, which include cholesterol, and positively and negatively charged lipids. The results are highly significant when designing vesicle formulations for applications in diagnostics and drug delivery.