Design and characterization of propolis extract loaded self-nano emulsifying drug delivery system as immunostimulant

This current study aims to optimize, characterize, and observe the stability of the self-nano emulsifying drug delivery system (SNEDDS) of propolis extract (PE) for improving the immune response. Optimization of the selected composition of SNEDDS was conducted using a D-optimal mixture design. SNEDDS was prepared by loading 150 mg/mL of PE in oil, surfactant, and cosurfactant phases. The thermodynamic stability test was carried out with phase separation parameters followed by the robustness to dilution and accelerated stability test. The immunostimulant activity was examined in vitro and in vivo by determining the phagocytic activity, cell proliferation, production of nitrite oxide levels of RAW 264.7 cells, phagocytic activity of macrophages, and the number of leukocytes, neutrophils, and lymphocytes. The formula optimization showed that the formula containing Capryol-90, Cremophor RH40, and PEG 400 at a ratio of 30: 34: 36 was optimum. The verification response of the optimum formula with drug loading showed that the transmittance, droplet size, and zeta potential were 96.90 ± 0.00%, 28.7 ± 1.20 nm, and -56.5 ± 2.05 mV, respectively. The thermodynamic stability test and robustness to dilution did not find any separation phase. The accelerated stability test results were classified as stable. The in vitro and in vivo immunostimulant activity test showed that PE-loaded SNEDDS exhibited a higher immunostimulant effect than PE. In conclusion, the optimum and stable composition of PE loaded SNEDDS was found with a simple and accurate method using the D-Optimal mixture design and demonstrated an immunostimulant activity.