Nanoencapsulation of carotenoid extract via the temperature-induced phase transition of triblock polymer in Supercritical Carbon dioxide (scCO2)

Objectives: Carotenoids are increasingly explored as nutraceuticals but their low bioavailability due to poor aqueous solubility limits their applications. This study discusses the development of a novel and organic solvent-free method to develop carotenoid-containing polymeric nanoparticles via temperature-induced phase transition (TIPT) of pluronic F-68 to obtain formulations with the improved dissolution of carotenoids.

Methods: The nanoencapsulation of carotenoids in pluronic F-68 was performed in supercritical carbon dioxide (scCO2) to avoid oxidative or temperature/solvent-induced degradation. The nanoen capsulates were prepared in scCO2 at 40 or 60 °C and 10 MPa without the aid of any organic solvent. The formulations thereafter were characterised for particle size via dynamic light scattering (DLS), particle morphology via Scanning Electron Microscopy (SEM) and carotenoid content/release via high-performance liquid chromatography (HPLC).

Key findings: HPLC results showed carotenoid degradation to be negligible in freshly prepared formulations when prepared in scCO2 at 60 °C and 10 MPa. The developed particles were spheroidal with sizes ranging between 150-250 nm depending on carotenoid content in the preparation. An improvement in the aqueous solubility and storage stability (5 ºC) of carotenoids was also observed for the formulations prepared in scCO2.

Conclusions: These results suggest that TIPT under scCO2 can be applied to formulate nanoparticulates with improved dissolution rate and stability of thermosensitive molecules such as carotenoids without causing any degradation during the processing.