Comprehensive study of α-terpineol-loaded oil-in-water (O/W) nanoemulsion: interfacial property, formulation, physical and chemical stability

Fabrication of Luteolin Nanoemulsion by Box-Behnken Design to Enhance its Oral Absorption Via Lymphatic Transport

Intestinal lymphatic transport offers an alternative and effective way to deliver drugs, such as avoiding first-pass metabolism, enhancing oral bioavailability, and facilitating the treatment of targeted lymphoid-related diseases. However, the clinical use of luteolin (LUT) is limited by its poor water solubility and low bioavailability, and enhancing lymphatic transport by nanoemulsion may be an efficient way to enhance its oral bioavailability. The objective of this work is to prepare the luteolin nanoemulsions (LUT NEs), optimized its preparation parameters by using Box-Behnken design optimization (BBD) and evaluated it in vitro and in vivo. An Caco-2 / Raji B cell co-incubation monolayer model was established to simulate the M-cell pathway, and the differences in the transmembrane transport of LUT and NEs were compared. Cycloheximide (CHX) was utilized to establish rat chylomicron (CM) blocking model, and for investigating the influence of pharmacokinetic parameters in rats thereafter. The results showed that LUT NEs have good stability, the particle sizes were about 23.87 ± 0.57 nm. Compared with LUT suspension, The Papp of LUT NEs was enhanced for 3.5-folds, the oral bioavailability was increased by about 2.97-folds. In addition, after binding with chylomicron, the oral bioavailability of LUT NEs was decreased for about 30% (AUC 0-∞ (μg/L*h): 5.356 ± 1.144 vs 3.753 ± 0.188). These results demonstrated that NEs could enhance the oral absorption of luteolin via lymphatic transport routes.

Evaluating the effects of surfactant types on the properties and stability of oil-in-water Rhodiola rosea nanoemulsion

Different types and ratios of surfactant, co-surfactant, and oil phase, have a greater impact on nanoemulsion preparation. The presence of surfactants in the nanoemulsion can reduce surface tension and characteristic stability. In this study, four groups of oil-in-water (O/W) nanoemulsions (NEs) with different ratios of surfactant and co-surfactant, and two oils were formulated as carriers of Rhodiola rosea. The variable optimization was investigated and then indicated as optimization group A (Opt A) with the formula of 10% of transcutol, 16.63% of tween 80, Opt B with 10% of tween 80, 29.87% of span 80, Opt C with 28.42% of transcutol, 30% of labrasol, and Opt D with 30% of transcutol, 30% of tween 80. Labrafac and soybean oil were used as the oil phase. The optimized formula using the response surface method (RSM) by design expert software showed the ideal conditions with a higher desirability score. Desirability score are 0.72% (Opt A), 0.81% (Opt B), 0.76% (Opt C) and 0.98% (Opt D), the desirability rating close to 1 indicates a high possibility that the projected values would closely match the experimental results for the optimum formula. All of the optimized formulation were also checked for the characteristics of nanoemulsion including particle size, polydispersity index (PDI), zeta potential, viscosity, encapsulation efficiency, transmission electron microscope (TEM), antioxidant activity, skin irritation test and stability studies. Our study provides a promising combination of surfactant-co-surfactant and oil phases to produce a stable nanoemulsion that can be used in pharmaceuticals and cosmetics in the future.