# Liposomes by thin-film hydration and extrusion

> Phospholipids such as phosphatidylcholine, usually with cholesterol, are dissolved in chloroform and the solvent is removed on a rotary evaporator, leaving a thin lipid film on the flask wall. Hydrating the film with an aqueous buffer above the lipids’ phase-transition temperature swells it into multilamellar vesicles. Extrusion through a polycarbonate membrane (or sonication) turns them into unilamellar liposomes, with hydrophilic drugs in the water core and hydrophobic drugs in the bilayer.

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- Open in the LabCanvas editor (LabCanvas account): https://www.labcanvas.com/editor.html?template=liposome-thin-film-hydration
- Updated: 2026-10-14
- Category: Nanomaterial synthesis
- Method: Thin-film hydration, bottom-up
- Starting materials: Phospholipids (e.g. phosphatidylcholine) and cholesterol in chloroform; aqueous buffer (± drug)
- Product: Unilamellar liposomes (LUVs or SUVs) carrying hydrophilic and/or hydrophobic drugs
- Typical size: MLVs are large and polydisperse; extrusion gives vesicles close to the membrane pore size
- Key result: Narrow size distribution after extrusion; lamellarity and loading depend on lipid composition
- Scalability: Low to medium: lab-scale batches; extrusion and solvent removal limit scale-up
- Figure: 1920 × 1080 px, 68 editable layers (15 generated objects with settings)

## Steps

1. **Dissolve the lipids**: Phospholipid and cholesterol (and a hydrophobic drug) in chloroform in a round-bottom flask
2. **Thin film**: Remove the solvent on a rotary evaporator under reduced pressure; dry the film thoroughly
3. **Hydration**: Add aqueous buffer (with a hydrophilic drug) above the lipid phase-transition temperature (Tm) and agitate: the film swells into multilamellar vesicles (MLVs)
4. **Size reduction**: Extrude repeatedly through a polycarbonate membrane (Hope et al.) or sonicate
5. **Liposomes**: Unilamellar vesicles; unencapsulated drug removed by dialysis or gel filtration

## Strengths

- Simple and versatile; works for most lipids
- Encapsulates both hydrophilic and hydrophobic drugs
- Extrusion gives controlled, reproducible sizes

## Limitations

- Uses organic solvents that must be removed completely
- Low encapsulation efficiency for hydrophilic drugs
- Hard to scale; batch-to-batch variability

## Uses

- Drug delivery (e.g. anticancer drugs)
- Vaccines and adjuvants
- Model membranes
- Cosmetics and nutraceuticals

## References

1. Bangham, Standish & Watkins, “Diffusion of univalent ions across the lamellae of swollen phospholipids”, J. Mol. Biol. 1965. https://doi.org/10.1016/S0022-2836(65)80093-6 (method origin)
2. Hope et al., “Production of large unilamellar vesicles by a rapid extrusion procedure: characterization of size distribution, trapped volume and ability to maintain a membrane potential”, Biochim. Biophys. Acta 1985. https://doi.org/10.1016/0005-2736(85)90521-8 (primary)
3. Akbarzadeh et al., “Liposome: classification, preparation, and applications”, Nanoscale Res. Lett. 2013. https://doi.org/10.1186/1556-276X-8-102 (review)

Credit: Redrawn and simplified after Bangham, Standish & Watkins, J. Mol. Biol. 1965 (doi:10.1016/S0022-2836(65)80093-6), Hope et al., Biochim. Biophys. Acta 1985 (doi:10.1016/0005-2736(85)90521-8) and Akbarzadeh et al., Nanoscale Res. Lett. 2013 (doi:10.1186/1556-276X-8-102).

## Questions

**What does the “Liposomes by thin-film hydration and extrusion” template show?** Phospholipids such as phosphatidylcholine, usually with cholesterol, are dissolved in chloroform and the solvent is removed on a rotary evaporator, leaving a thin lipid film on the flask wall. Hydrating the film with an aqueous buffer above the lipids’ phase-transition temperature swells it into multilamellar vesicles. Extrusion through a polycarbonate membrane (or sonication) turns them into unilamellar liposomes, with hydrophilic drugs in the water core and hydrophobic drugs in the bilayer.

**What are the steps shown in “Liposomes by thin-film hydration and extrusion”?** 1. Dissolve the lipids: Phospholipid and cholesterol (and a hydrophobic drug) in chloroform in a round-bottom flask. 2. Thin film: Remove the solvent on a rotary evaporator under reduced pressure; dry the film thoroughly. 3. Hydration: Add aqueous buffer (with a hydrophilic drug) above the lipid phase-transition temperature (Tm) and agitate: the film swells into multilamellar vesicles (MLVs). 4. Size reduction: Extrude repeatedly through a polycarbonate membrane (Hope et al.) or sonicate. 5. Liposomes: Unilamellar vesicles; unencapsulated drug removed by dialysis or gel filtration.

**What are the starting materials and the product?** Starting materials: Phospholipids (e.g. phosphatidylcholine) and cholesterol in chloroform; aqueous buffer (± drug). Product: Unilamellar liposomes (LUVs or SUVs) carrying hydrophilic and/or hydrophobic drugs.

**Which papers is “Liposomes by thin-film hydration and extrusion” based on?** Bangham, Standish & Watkins, “Diffusion of univalent ions across the lamellae of swollen phospholipids”, J. Mol. Biol. 1965 (doi:10.1016/S0022-2836(65)80093-6); Hope et al., “Production of large unilamellar vesicles by a rapid extrusion procedure: characterization of size distribution, trapped volume and ability to maintain a membrane potential”, Biochim. Biophys. Acta 1985 (doi:10.1016/0005-2736(85)90521-8); Akbarzadeh et al., “Liposome: classification, preparation, and applications”, Nanoscale Res. Lett. 2013 (doi:10.1186/1556-276X-8-102).

**Can I edit the “Liposomes by thin-film hydration and extrusion” template?** Yes. Open it in the LabCanvas editor: all 68 layers are editable, including 15 generated objects (structures, plots, equipment) with their own settings. Change the text, colours and layout, then export PNG, TIFF, SVG or PDF.

**Do I need an account to use this template?** Not to view it here. To open and edit it, sign in to LabCanvas or create a free account (the free plan keeps one design of each kind). Downloading the figure is part of LabCanvas Pro (US$19 a month or US$199 a year).