The Science of Liposomal Delivery
Short answer: Liposomes are microscopic phospholipid vesicles that can protect sensitive actives from digestion and help deliver them across biological membranes. The promise is increased bioavailability for compounds that are otherwise poorly absorbed; however, not all products labelled “liposomal” are identical, and formulation quality determines performance.
How liposomes change oral absorption
Liposomes mimic cellular phospholipid bilayers. A molecule encapsulated in a stable liposome can be shielded from stomach acid and degradative enzymes, and the liposomal carrier may fuse with or be taken up by enterocytes, allowing more of the active to reach systemic circulation than a plain oral dose.
What the clinical literature shows
Systematic reviews and mechanistic reviews of nanovesicle strategies describe how liposomal or phospholipid carriers can increase oral bioavailability across multiple actives and highlight that the effect depends on the vesicle design and manufacturing method (see a review on nanovesicle-mediated oral bioavailability enhancement: Ren et al., International Journal of Nanomedicine, 2022. https://pubmed.ncbi.nlm.nih.gov/36262189/).
Randomised clinical evidence shows that some liposomal formulations do increase plasma exposure compared with non‑liposomal forms. For example, “Liposomal delivery enhances absorption of vitamin C into plasma and leukocytes: a double‑blind, placebo‑controlled, randomized trial.” European Journal of Nutrition, 2024. https://pubmed.ncbi.nlm.nih.gov/39237620/ — the trial reported higher plasma and leukocyte vitamin C with a liposomal preparation versus control. Limitation: bioavailability gains vary widely between formulations and between actives.
Practical prescription points for clinicians
- Evidence for liposomal advantage is active‑specific. Always check whether the active has RCT evidence for a particular liposomal product or delivery method.
- Manufacturing matters: ultrasonic or high‑energy methods, phospholipid quality and vesicle size distribution change performance.
- When prescribing a compounded liposomal product, document the target dose and how the preparation should be analysed or verified (for example, total encapsulated content and vesicle size), because trial results for one formulation do not automatically apply to another.
Clinical and regulatory caveat
Randomised trials and reviews describe the behaviour of actives and of specific liposomal formulations — they do not validate a given pharmacy’s in‑house product unless that product is matched analytically to the studied formulation. Use a prescription‑led route to align the compounding specification with the clinical evidence.