Production of liposomes loaded with antioxidants using a supercritical CO2 assisted process

•Lipophilic antioxidants were successfully entrapped in liposome double layer.•The supercritical process allowed preserving the antioxidant power.•The inclusion of the drug in the lipid membrane did not alter vesicles stability.

To preserve benefic effects of antioxidants, they can be protected using a drug carrier. Conventional processes for the production of antioxidants-loaded carriers suffer of some drawbacks that can be overcome using Supercritical Assisted Liposome Formation (SuperLip). In this work, SuperLip was used to encapsulate an amphiphilic (eugenol, EUG) and a lipophilic (α-lipoic acid, ALA) antioxidant in liposome vesicles. EUG loaded liposomes were produced with a mean diameter of about 200 nm and demonstrated to be stable for at least 40 days. Eugenol was entrapped in the inner core and in the lipophilic double layer, with Encapsulation Efficiencies (EE) up to 94.2 ± 2.9%. Liposomes with a mean diameter of about 230 nm loaded with ALA in the lipidic layer were also successfully produced, with EE up to 68.1 ± 6.1%.Free-radical scavenging assay results indicated that EUG and ALA antioxidant power was preserved after processing; a reduction of the inhibition power, compared to the un-processed molecule, in the range between 6% and 13% was obtained. Drug release tests were also performed at 30 °C and 60 °C, showing that these liposomes are temperature sensitive.

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