Hemp Therapies Wiki / Liposomal Delivery Systems

Liposomal Stability and Storage

Liposomal formulations degrade over time through two primary chemical pathways, and how a product is stored has a measurable effect on how fast that degradation happens.

Degradation Pathways

Liquid liposome formulations are subject to two primary degradation pathways: hydrolysis of the phospholipid molecules and oxidation of unsaturated fatty acid chains. Phospholipid hydrolysis occurs when water molecules break the ester bonds within phospholipid molecules, producing lysophospholipids and free fatty acids that can destabilize the vesicle wall. Reported hydrolysis rates for liposomal suspensions increase at pH levels below 6.0 or above 8.0, and the reaction rate has been described as roughly doubling with each 10°C increase in storage temperature above standard refrigeration. Oxidative degradation is driven by oxygen exposure acting on unsaturated fatty acid chains within the phospholipid membrane, and is reported to occur more readily in egg- or soy-derived phosphatidylcholine than in more saturated lipid sources.

Shelf Life by Format

Liquid liposome products are commonly assigned a shelf life of roughly 12 to 24 months when stored under refrigeration. Solid liposomal formats produced through freeze-drying or spray-drying are reported to reach longer shelf-life ranges, cited at roughly 36 to 60 months at room temperature, compared with liquid formulations. Small amounts of antioxidant ingredients are sometimes added during processing to help limit oxidative degradation of the phospholipid membrane during storage.

Consumer Storage Guidance

General consumer storage guidance for liposomal liquid supplements includes keeping the product in a cool, dark location away from direct heat and light exposure.

Summary

Liposomal liquids degrade through hydrolysis and oxidation, both of which accelerate with heat and pH extremes, which is why liquid formats carry shorter shelf lives and refrigeration guidance compared with solid, freeze-dried or spray-dried formats.