Optimization of coenzyme Q10 encapsulation in liposomes using supercritical carbon dioxide

Abstract

Coenzyme Q10 (CoQ10)-loaded liposomes were prepared with soy lecithin utilizing a single step supercritical carbon dioxide (SCCO2) method, which did not require the use of organic solvents, buffers or surfactants. The effects of pressure, temperature, pressurization rate and CoQ10-to-lecithin ratio on bioactive loading (BL), particle size (Ps) and polydispersity index (PdI) were investigated and modeled by response surface methodology (RSM). Pressure and concentration of CoQ10 had a great influence on the three responses. High pressures led to lower BLs, but also particles with smaller Ps and PdI. High concentrations of CoQ10 allowed obtaining higher BLs and lower PdI, but also higher Ps. High pressurization rates were needed to obtain high BLs, but, in contrast, it also led to higher PdIs. Temperature had a positive influence only on the PdI. The optimum conditions predicted by the model to simultaneously maximize the BL and minimize the Ps and PdI were 30 MPa, 40 °C, 6 MPa∙min−1 and 17 mol% CoQ10 (BL of 4.2 %, Ps of 177 nm and PdI of 0.313). Furthermore, encapsulation efficiencies between 87.6–99.7 % were achieved and semi-spherical stable particles (zeta potential ≈ −70 mV) were formed. Differential scanning calorimetry indicated a potential loss of crystallinity upon the encapsulation of CoQ10 into the liposomes. The findings reveal the great potential of this SCCO2 method for the encapsulation of CoQ10 in liposomes.