In order to take advantage of CF processing while avoiding the use of severe working conditions, NANOMOL scientists have also developed a procedure based on the DELOS method for the production of unilamellar vesicles. This method, DELOS‑SUSP, involves the depressurization of a CO2-expanded liquid solution of lipids into an aqueous phase using milder conditions of pressure (10 MPa) and temperature (308 K) than most of the described methodologies, which are performed at pressures up to 25 MPa and temperatures of approximately 333 K. Lower temperatures allow the processing of heat-labile compounds, while milder pressures would reduce the capital cost of a high-pressure plant when scaling up the process.

Incorporation of cholesterol in the lipid membrane of vesicles is sometimes required in order to reduce their permeability and avoid leakage of the encapsulated active molecule. Owing to the low aqueous solubility of cholesterol, the preparation of cholesterol-rich vesicles by conventional hydration procedures is problematic. Using DELOS‑SUSP the authors prepared cholesterol-rich vesicles formed by an equimolar percentage of this lipid and the cationic surfactant cetyltrimethylammonium bromide (CTAB).

The potential of DELOS‑SUSP for the encapsulation of biologically active compounds has been tested in several drugs and biomolecules (peptides, proteins and nucleic acids). The simplicity of the method allows the onestep preparation of loaded or unloaded vesicles on a broad range of scales. Indeed, a simple 6 ml non-commercial reactor, which produces nearly 30 ml of vesicles, and a 300 ml reactor that allows the preparation of more than 1 l of vesicles per batch, lead to very similar uniform nanovesicles This versatility in batch size allows work with expensive molecules at a small scale, and provides, at the same time, the possibility to scale-up the process for the bulk production of vesicles without losing their characteristics.


To see more about DELOS-SUSP process:

  • Preparation of Uniform Rich Cholesterol Unilamellar Nanovesicles Using CO2-Expanded Solvents
    Langmuir, 24, 2433-2437 (2008)
    M. Cano-Sarabia, N. Ventosa, S. Sala, C. Patiño, R. Arranz, J. Veciana


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