A nano-delivery system for bioactive ingredients using supercritical carbon dioxide and its release behaviors

•Nano-scale liposomes can be produced using supercritical carbon dioxide (SC-CO2).•SC-CO2-produced liposomes exhibit superior enteric solubility.•The chemical free liposomes are obtained after processing.•The liposomes using SC-CO2 are stable during storage.

For the purpose of ensuring the bioavailability of bioactive ingredients, a nano-delivery system with low toxicity was developed using supercritical carbon dioxide (SC-CO2). Compared to thin-film hydration (TFH), obtaining nano-scale liposomes is easier using SC-CO2. The characteristic of these liposomes was also demonstrated by the analysis of particle size and morphology. An in vitro release study showed that liposomes produced using SC-CO2 were resistant to low pH in simulated gastric conditions. In a simulated intestinal environment, enteric solubility of these liposomes was enhanced, which are important properties for controlled releasing bioactive ingredient. Furthermore, SC-CO2-produced liposomes had a higher storage stability than those produced using TFH. Analysis of the organic solvent residue in the liposomes by gas chromatography-mass spectrometry (GC-MS) indicated that SC-CO2-produced liposomes had lower toxicity than those produced by TFH. A chemical free nano-delivery system using SC-CO2 has been revealed for storage and controlled release of bioactive ingredients.