Flavonoids have diverse beneficial roles that potentiate their application as nutraceutical agents in nutritional supplements and as natural antimicrobial agents in food preservation. To address poor solubility and bioactivity issues, we developed water-soluble micellar formulations loaded with single and multiple flavonoids using the biocompatible surface-active ionic liquid choline oleate. The food preservation performance was investigated using luteolin, naringenin, and quercetin as model bioactive compounds. The micellar formulations formed spherical micelles with particle sizes of <150 nm and exhibited high aqueous solubility (>5.15 mg/mL). Co-delivery of multiple flavonoids (luteolin, naringenin, and quercetin in LNQ-MF) resulted in 84.85% antioxidant activity at 100 μg/mL. The effects on Staphylococcus aureus and Salmonella enterica were synergistic with fractional inhibitory concentration indices of 0.87 and 0.71, respectively. LNQ-MF hindered the growth of S. aureus in milk (0.83-0.89 log scale) compared to the control. Co-delivered encapsulated flavonoids are a promising alternative to chemical preservatives.
Herein, we report ethosome (ET) formulations composed of a safe amount of 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC)-based ionic liquid with various concentrations of ethanol as a carrier for the transdermal delivery of a high molecular weight drug, insulin. The Insulin-loaded ET vesicles exhibited long-term stability compared to conventional DMPC ETs, showing significantly higher drug encapsulation efficiency and increased skin permeation ability.
Transdermal insulin delivery is a promising method for diabetes management, providing the potential for controlled, sustained release and prolonged insulin effectiveness. However, the large molecular weight of insulin hinders its passive absorption through the stratum corneum (SC) of the skin, and high doses of insulin are required, which limits the commercial viability. We developed ethosome (ET) and trans-ethosome (TET) nanovesicle formulations containing a biocompatible lipid-based ionic liquid, [EDMPC][Lin], dissolved in 35% ethanol. TET formulations were obtained by adding isopropyl myristate (IPM), Tween-80, or Span-20 as surfactants to ET formulations. Dynamic light scattering, ζ-potential, transmission electron microscopy, and confocal laser scanning microscopy studies revealed that the nanovesicles had a stable particle size. The formulations remained stable at 4 °C for more than 3 months. ET and TET formulations containing IPM (TET1) significantly (p < 0.0001) enhanced the transdermal penetration of FITC-tagged insulin (FITC-Ins) in both mouse and pig skin, compared with that of the control FITC-Ins solution and other TET formulations, by altering the molecular structure of the SC layer. These nanovesicles were found to be biocompatible and nonirritants (cell viability >80%) in the in vitro and in vivo studies on three-dimensional (3D) artificial human skin and a diabetic mouse model, respectively. The ET and TET1 formulations were applied to the skin of diabetic mice at an insulin dosage of 30 IU/kg. The nanovesicle formulations significantly reduced blood glucose levels (BGLs) compared with the initial high BGL value (>150 mg/dL). The nanovesicle-treated mice maintained low BGLs for over 15 h, as opposed to only 2 h in the injection group. The ET and TET1 formulations reduced the BGLs by 62 and 34%, respectively, of the initial value. These ET and TET1 formulations have a high potential for use in commercial transdermal insulin patches, enhancing comfort and adherence in diabetes treatment.