Nanostructured lipid carriers for delivery of free phytosterols: Effect of lipid composition and chemical interesterification on physical stability

"Characterization and stability of α-tocopherol loaded solid lipid nanoparticles formulated with different fully hydrogenated vegetable oils"

Solid lipid nanoparticles can be compatible with several bioactive compounds and confer a differentiated crystalline structure. This study aimed to produce α-tocopherol loaded solid lipid nanoparticles with fully hydrogenated oils and fats from palm oil, soybean oil, and crambe oil, by high-pressure homogenization, using lecithin as an emulsifier. After recrystallization of solid lipid nanoparticles, dispersions were evaluated until 60 days of storage for particle size, polydispersity index, zeta potential, microstructure, dispersion stability and α-tocopherol quantification. α-tocopherol loaded solid lipid nanoparticles showed particle sizes and zeta potential values considered adequate for this type of particle. Presence of α-tocopherol altered thermal behavior of the particles, leading to increased crystallinity, with no changes in polymorphism, when compared to the unloaded solid lipid nanoparticles. All α-tocopherol loaded solid lipid nanoparticles dispersions showed stability with no losses of α-tocopherol, indicating their potential as a carrier for this compound in fortified foods.

QbD-driven development of phospholipid-embedded lipidic nanocarriers of raloxifene: extensive in vitro and in vivo evaluation studies

Raloxifene (RLX) is popularly indicated in treatment of osteoporosis and prevention of breast cancer. Owing to its poor aqueous solubility, high pre-systemic metabolism, intestinal glucuronidation, and P-glycoprotein (P-gp) efflux, however, it demonstrates low (< 2%) and inconsistent oral bioavailability. The current work, Quality by Design (QbD)-driven development of phospholipid-embedded nanostructured lipidic carriers (NLCs) of RLX, accordingly, was undertaken to potentiate its lymphatic uptake, augment oral bioavailability, and possibly reduce drug dosage. Factor screening and failure mode effect analysis (FMEA) studies were performed to delineate high-risk factors using solid lipid (glyceryl monostearate), liquid lipid (vitamin E), and surfactant (Tween 80). Response surface optimization studies were performed employing the Box-Behnken design. Mathematical and graphical methods were adopted to embark upon the selection of optimized NLCs with various critical quality attributes (CQAs) of mean particle size as 186 nm, zeta potential of - 23.6 mV, entrapment efficiency of 80.09%, and cumulative drug release at 12 h of 83.87%. The DSC and FTIR studies, conducted on optimized NLCs, indicated successful entrapment of drug into the lipid matrix. In vitro drug release studies demonstrated Fickian diffusion mechanism. In vivo pharmacokinetic studies in rats construed significant improvement in AUC0-72 h (4.48-folds) and in Cmax (5.11-folds), unequivocally indicating markedly superior (p < 0.001) oral bioavailability of RLX-NLCs vis-à-vis marketed tablet formulation. Subsequently, level "A" in vitro/in vivo correlation (IVIVC) was also successfully attempted between the percentages of in vitro drug dissolved and of in vivo drug absorbed at the matching time points. In vitro cytotoxicity and cellular uptake studies also corroborated higher efficacy and successful localization of coumarin-6-loaded NLCs into MG-63 cells through microfluidic channels.

Current and New Insights on Delivery Systems for Plant Sterols in Food

Plant sterols are minor bioactive components of food lipids, which are often used for the formulation of functional foods due to their cholesterol-lowering properties. However, they have low solubility and tend to crystallize, which may affect their biological effects, the sensory profile of the sterol-enriched food, and its consumer acceptability. Moreover, due to the unsaturated structure of sterols, they are susceptible to oxidation, so different encapsulation systems have been developed to improve their dispersibility/solubility, stability, delivery, and bioaccessibility. This chapter provides an overview of the main encapsulation systems currently used for plant sterols and their application in model and food systems, with a particular focus on their efficiency and impact on sterol bioaccessibility.

Assembly of nanostructured lipid carriers loaded gefitinib and simvastatin as hybrid therapy for metastatic breast cancer: Codelivery and repurposing approach

Breast cancer represents a life-threatening problem globally. The major challenge in the clinical setting is the management of cancer resistance and metastasis. Hybrid therapy can affect several cellular targets involved in carcinogenesis with a lessening of adverse effects. Therefore, the current study aims to assemble, and optimize a hybrid of gefitinib (GFT) and simvastatin (SIM)-loaded nanostructured lipid carrier (GFT/SIM-NLC) to combat metastatic and drug-resistant breast cancer. GFT/SIM-NLC cargos were prepared using design of experiments to investigate the impact of poloxamer-188 and fatty acids concentrations on the physicochemical and pharmaceutical behavior properties of NLC. Additionally, the biosafety of the prepared GFT/SIM-NLC was studied using a fresh blood sample. Afterward, the optimized formulation was subjected to an MTT assay to study the cytotoxic activity of GFT/SIM-NLC compared to free GFT/SIM using an MCF-7 cell line as a surrogate model for breast cancer. The present results revealed that the particle size of the prepared NLC ranged from (209 to 410 nm) with a negative zeta potential value ranging from (-17.2 to -23.9 mV). Moreover, the optimized GFT/SIM-NLC formulation showed favorable physicochemical properties and promising lymphatic delivery cargos. A biosafety study indicates that the prepared NLC has a gentle effect on erythrocyte hemolysis. Cytotoxicity studies revealed that GFT/SIM-NLC enhanced the killing of the MCF-7 cell line compared to free GFT/SIM. This study concluded that the hybrid therapy of GFT/SIM-NLC is a potential approach to combat metastatic and drug-resistant breast cancer.

Solubilization of free β-sitosterol in milk sphingomyelin and polar lipid vesicles as carriers: Structural characterization of the membranes and sphingosome morphology

High consumption of plant sterols reduces the risk of cardiovascular diseases in humans and provides health benefits. Increasing the amount of plant sterols in the diet is therefore necessary to reach the recommended daily dietary intake. However, food supplementation with free plant sterols is challenging because of their low solubility in fats and water. The objectives of this study were to investigate the capacity of milk-sphingomyelin (milk-SM) and milk polar lipids to solubilise β-sitosterol molecules in bilayer membranes organised as vesicles called sphingosomes. The thermal and structural properties of milk-SM containing bilayers composed of various amounts of β-sitosterol were examined by differential scanning calorimetry (DSC) and temperature-controlled X-ray diffraction (XRD), the molecular interactions were studied using the Langmuir film technique, the morphologies of sphingosomes and β-sitosterol crystals were observed by microscopy. We showed that the milk-SM bilayers devoid of β-sitosterol exhibited a gel to fluid L_α phase transition for T_m = 34.5 °C and formed facetted spherical sphingosomes below T_m. The solubilisation of β-sitosterol within milk-SM bilayers induced a liquid-ordered L_o phaseabove 25 %mol (1.7 %wt) β-sitosterol and a softening of the membranes leading to the formation of elongated sphingosomes. Attractive molecular interactions revealed a condensing effect of β-sitosterol on milk-SM Langmuir monolayers. Above 40 %mol (25.7 %wt) β-sitosterol, partitioning occured with the formation of β-sitosterol microcrystals in the aqueous phase. Similar results were obtained with the solubilization of β-sitosterol within milk polar lipid vesicles. For the first time, this study highlighted the efficient solubilization of free β-sitosterol within milk-SM based vesicles, which opens new market opportunities for the formulation of functional foods enriched in non-crystalline free plant sterols.

Cod liver oil nano-structured lipid carriers (Cod-NLCs) as a promising platform for nose to brain delivery: Preparation, in vitro optimization, ex vivo cytotoxicity & in vivo biodistribution utilizing radioiodinated zopiclone

Nano-structured lipid carriers containing zopiclone were prepared as a targeted drug delivery system to convey zopiclone directly to brain via nasal route. Nano-structured lipid carriers were constructed adopting hot emulsification-ultrasonication method using palmitic acid in place of the solid lipid, cod liver oil as liquid lipid, and poloxamer 407 as a surfactant. A three-factor three-level central composite face-centered design was used to optimize the formulated nano-structured lipid carriers. The independent factors were lipid amount (X₁), surfactant amount (X₂), and sonication time (X₃). The examined responses were entrapment efficiency (EE,Y₁,%), particle size (PS,Y₂,nm), zeta potential(mV), polydispersity index(PDI,Y₃), in vitro release(Q8h,Y₄,%) and dissolution efficiency (DE,Y₅,%). The optimum formula showed high entrapment efficiency of 94.31% ± 2.44, in vitro drug release of 83.89% ± 1.77 with dissolution efficiency equals 88.63% ± 2.01, small particle size of 71.27 nm ± 13.57 and low polydispersity index 0.097 ± 0.15. In vivo biodistribution in mice was evaluated by a radiobiological technique using radioiodinated zopiclone([¹³¹I]iodo-ZP). Results revealed the superiority of the intranasal route to deliver zopiclone directly to brain faster and higher brain uptake (6.9 ± 1.02%ID/g at 5 min post-administration). The current study confirmed that intranasal administration of nano-structured lipid carriers had great potential as an effective tool for targeted brain zopiclone delivery for insomnia treatment.