In vitro scleral lutein distribution by cyclodextrin containing nanoemulsions

Cyclodextrin-Based Polymeric Materials Bound to Corona Protein for Theranostic Applications

Cyclodextrins (CDs) are cyclic oligosaccharide structures that could be used for theranostic applications in personalized medicine. These compounds have been widely utilized not only for enhancing drug solubility, stability, and bioavailability but also for controlled and targeted delivery of small molecules. These compounds can be complexed with various biomolecules, such as peptides or proteins, via host-guest interactions. CDs are amphiphilic compounds with water-hating holes and water-absorbing surfaces. Architectures of CDs allow the drawing and preparation of CD-based polymers (CDbPs) with optimal pharmacokinetic and pharmacodynamic properties. These polymers can be cloaked with protein corona consisting of adsorbed plasma or extracellular proteins to improve nanoparticle biodistribution and half-life. Besides, CDs have become famous in applications ranging from biomedicine to environmental sciences. In this review, we emphasize ongoing research in biomedical fields using CD-based centered, pendant, and terminated polymers and their interactions with protein corona for theranostic applications. Overall, a perusal of information concerning this novel approach in biomedicine will help to implement this methodology based on host-guest interaction to improve therapeutic and diagnostic strategies.

Encapsulation of Capsaicin in Whey Protein and OSA-Modified Starch Using Spray-Drying: Physicochemical Properties and Its Stability

The poor water-solubility and stability of capsaicin limits its widespread application in the industry. Spray-dried capsaicin microcapsules were fabricated using whey protein (WP) and octenyl-succinic-anhydride-modified starch (OS) as wall materials in this study. The aim is to investigate the impact of protein/starch ratio on microcapsules’ physicochemical characteristics and stability. SEM images showed that microcapsule granules were uneven in size, and irregular, with some wrinkles and dents. FTIR illustrated a chemical interaction between capsaicin and composite wall materials. XRD showed that the spray-dried powders were mainly in amorphous form. As the whey protein content decreased, the yield (9.32–68.18%), encapsulation efficiency (49.91–94.57%), wettability (158.87–232.63 s), and solubility (74.99–96.57%) of samples decreased, but the mean particle size (3.22–26.03 μm), apparent viscosity, and shear stress tended to increase. Besides, DSC revealed that the glass transition temperatures (Tg) of samples were at around 85 °C. Capsaicin microcapsules with WP:OS at the ratio of 7:3 possessed the highest Tg, and the best storage stability. Based on our research, microencapsulation significantly improved the stability and the water-solubility of capsaicin. A small amount of OSA-starch mixed with whey protein as a promising carrier for capsaicin would greatly promote the application of capsaicin in the food industry.

In Situ Measuring Partition Coefficient at Intact Nanoemulsions: A New Application of Single-Entity Electrochemistry

We report a new application of the single-entity electrochemistry (SEE) to in situ measure a partition coefficient at intact nanoemulsions (NEs). The partition coefficient at intact NEs is the most crucial physicochemical property to determine the uptake of delivery molecules inside NEs. It, however, has not been unequivocally elucidated by currently existing techniques based on ex situ measurements. Herein, we apply the single-entity electrochemistry (SEE) to directly and quantitatively measure the partition coefficient at NEs in situ. In this work, we use NEs featured with amphiphilic triblock copolymer (Pluronic F-127) as a model system to extract/preconcentrate 2-aminobiphenyl (2-ABP) dissolved in the water and demonstrate a new application of SEE to in situ quantitatively estimate the amounts of 2-ABP distributed into each intact NE. Our SEE measurements reveal that the partitioning is governed by extraction of 2-ABP inside NEs rather than its adsorption on the NE surface, and this extraction is remarkably efficient with up to ∼8 orders of magnitude of the preconcentration factor, thus leading to the unprecedentedly large partition coefficient of 1.9 (±1.4) × 10¹⁰. This result implies that not only the thermodynamic distribution but also the intermolecular interaction of extracted compounds inside NEs could play a significant role in the apparent partition coefficient (P = 1.9 (±1.4) × 10¹⁰). The experimentally determined partition coefficient was validated by molecular dynamics (MD) simulations with showing a stabilizing role of intermolecular interaction in the partitioned system. We further verified our methodology with other compounds exhibiting aromatic properties, e.g., ferrocenemethanol. Significantly, our new approach can be readily applicable to investigate practical NEs commercially marketed for drug, food, and cosmetics.

Nutraceutical approach to enhance lutein bioavailability via nanodelivery systems

Lutein, a potent dietary carotenoid, has considerable biological activity and confers protection against age-related macular degeneration. Its bioavailability following consumption, however, depends on its rate of degradation. Nanodelivery systems with improved efficacy and stability are currently being developed to increase the bioavailability of lutein. This review examines nutraceutical approaches used in the development of such nanodelivery systems. It describes the methods of lutein preparation, the characteristics of various delivery systems, and the lutein delivery profile. In order to enhance lutein loading, provide electrostatic stabilization, and achieve the controlled release of lutein, adjuvants such as dextran moieties, whey proteins, medium-chain triglycerides, and chitosan polymers can be used to effectively reduce the particle size (< 70 nm) and improve encapsulation efficiency (to 99.5%). The improved bioavailability of lutein via nanocrystals incorporated into rapidly dissolving films for oral consumption is a new area of exploratory research. This review aims to provide clarity about current research aimed at enhancing the bioavailability of lutein through the development of nanodelivery systems.

Development and evaluation of lutein-loaded alginate microspheres with improved stability and antioxidant

BACKGROUND

Lutein has been of great interest to the food processing and pharmaconutrient industries owing to its beneficial effects on human health. However, lutein is very sensitive to heat, light, pH and oxidative conditions, which limits its application in food systems. The present study aimed to prepare lutein-alginate microspheres by a calcium chloride gelation method with the purpose of improving the stability and antioxidant abilities of lutein.

RESULTS

The loading capacity of lutein in the microspheres was approximately 5.3% (w/w) and the entrapment efficiency was about 63%. The loaded microspheres were nearly spherical with an average size of 150 μm. They exhibited a crimped surface by scanning electron microscopy. The lutein was in amorphous state by X-ray powder diffraction. Analysis by Fourier transform infrared spectroscopy and molecular docking revealed an intermolecular hydrogen bond interaction between lutein and sodium alginate. In vitro release experiments showed that the microspheres presented slower release at acidic conditions than at neutral intestinal conditions. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity of the microencapsulated lutein was higher than that of free lutein. The stability of lutein in the microspheres was improved significantly when compared with that of free lutein at various temperatures.

CONCLUSION

The present work successfully developed well-protected lutein-alginate microspheres. This indicates that it is feasible to use microspheres loaded with lutein as antioxidant functional ingredients in food products. © 2019 Society of Chemical Industry.

Physicochemical Properties of Lutein-Loaded Microcapsules and Their Uptake via Caco-2 Monolayers

Lutein is one of the most important carotenoids that can be utilized in foods as a natural pigment and nutraceutical ingredient to improve eye health. However, its utilization is limited due to its poor solubility. Chemically, the highly unsaturated structure of lutein makes it extremely susceptible to light, oxygen, heat, and pro-oxidants and therefore easily oxidized, decomposed or dissociated. In this study, we aimed to imbed natural lutein to improve its storage stability and enhance its water dispersibility. As two commonly studied water-soluble and water-insoluble food-grade surfactants, lecithin and sodium caseinate (NaCas) were chosen as the wall materials, and lutein-loaded lecithin microcapsules and NaCas microcapsules were prepared, the results revealed the lutein-loaded NaCas microcapsules not only exhibited better solubility and stability than those of lutein-loaded lecithin microcapsules, but also were more stable when stored at 4 °C, 25 °C, 37 °C. Moreover, the lutein-loaded NaCas microcapsules were more easily absorbed by the intestinal Caco-2 cells than natural lutein. Considering the dispersibility, stability and cell absorption effect, the NaCas-based microparticle is a potential carrier for lutein.

Cyclodextrins and topical drug delivery to the anterior and posterior segments of the eye

It is generally believed that it is virtually impossible to obtain therapeutic drug concentrations in the posterior segment of the eye after topical application of aqueous, low viscosity eye drops. Thus, intravitreal drug injections and drug implants are currently used to treat diseases in the posterior segment such as macular edema. Here it is described how, through proper analysis of the drug permeation barriers and application of well-known pharmaceutical excipients, aqueous eye drops are designed that can deliver lipophilic drugs to the posterior segment as well as how such eye drops can maintain high drug concentrations in the anterior segment. Through stepwise optimization, eye drops containing solid drug/cyclodextrin complex microparticles with a mean diameter of 2-4μm, dissolved drug/cyclodextrin complex nanoparticles and dissolved drug molecules in an aqueous eye drop media of low viscosity were designed. After administration of the eye drops the microparticles slowly dissolved and maintained close to saturated drug concentrations in the aqueous tear fluid for several hours. Studies in rabbits and clinical evaluations in humans, using dorzolamide and dexamethasone as sample drugs, show that the eye drops deliver significant amounts of drugs to both the posterior segment and anterior segment of the eye. Clinical studies indicate that the eye drops can replace intravitreal injections and implants that are currently used to treat ophthalmic diseases and decrease frequency of drug administration, both of which can improve patient compliance.

Quercetin delivery to porcine cornea and sclera by solid lipid nanoparticles and nanoemulsion

Two potential nanocarriers including nanoemulsions and solid lipid nanoparticles have been demonstrated as vehicles for quercetin encapsulation and ocular delivery.