Improved Bioavailability of β-Carotene by Amorphous Solid Dispersion Technology in Rats

[ADMET Analysis of Amorphous β-Carotene and Its Usefulness Evaluation]

In recent years, functional foods have attracted increasing attention due to growing health consciousness. When functional food ingredients are poorly water-soluble, they largely fail to be absorbed due to their low solubility in the digestive tract, limiting their ability to exert their functions. To develop poorly water-soluble compounds into viable functional food ingredients, it is important to increase their gastrointestinal absorption so that they can fully exert their functions, and to ensure their safety and efficacy through ADMET research. β-Carotene exerts physiological activities including antioxidant effects, and functions as a source of vitamin A, but it is completely insoluble in water, so it is poorly absorbed from the digestive tract, rendering it difficult to use efficiently as a functional food ingredient. To overcome this problem, we are conducting research on drug delivery system to improve β-carotene solubility and thereby improve its digestive absorption by applying our unique amorphous solid dispersion production technology. To date, we have produced amorphous solid dispersions with dramatically improved water solubility by adding polymers and emulsifiers to β-carotene and kneading these mixtures under heat. The resultant amorphous solid dispersion showed unprecedentedly high gastrointestinal absorption, enhanced inhibition of allergic dermatitis, and enhanced amelioration of cognitive impairment. No major safety issues associated with long-term continuous administration were observed. In this paper, we introduce our efforts to effectively deliver poorly water-soluble compounds such as β-carotene in functional foods.

Isothiocyanate-functionalized silica as an efficient heterogeneous catalyst for carotenoid isomerization

Daily consumption of carotenoids is associated with multiple health benefits, but their bioavailability is generally extremely low. In this context, the Z-isomerization is receiving attention as a method for increasing carotenoid bioavailability because this approach is superior to conventional physical approaches. Here we investigated the feasibility of using isothiocyanate-functionalized silica (Si-NCS) as a heterogeneous catalyst for carotenoid isomerization. We found that this catalyst promoted Z-isomerization of (all-E)-carotenoids with high efficiency, e.g., when lycopene and astaxanthin solutions were incubated at 50 °C with 10 mg/mL Si-NCS, their total Z-isomer ratios increased by approximately 80 and 50 %, respectively. Furthermore, the Z-isomerization was successfully performed continuously by introducing carotenoid solution into a column packed with Si-NCS. Materials rich in carotenoid Z-isomers have not been used in practical applications due to high production cost and quality limitations (e.g., low Z-isomer ratio). The use of Si-NCS has sufficient potential to solve both these issues.

Formulation Approaches to Crystalline Status Modification for Carotenoids: Impacts on Dissolution, Stability, Bioavailability, and Bioactivities

Carotenoids, including carotenes and xanthophylls, have been identified as bioactive ingredients in foods and are considered to possess health-promoting effects. From a biopharmaceutical perspective, several physicochemical characteristics, such as scanty water solubility, restricted dissolution, and susceptibility to oxidation may influence their oral bioavailability and eventually, their effectiveness. In this review, we have summarized various formulation approaches that deal with the modification of crystalline status for carotenoids, which may improve their physicochemical properties, oral absorption, and biological effects. The mechanisms involving crystalline alteration and the typical methods for examining crystalline states in the pharmaceutical field have been included, and representative formulation approaches are introduced to unriddle the mechanisms and effects more clearly.

Physicochemical and Biochemical Evaluation of Amorphous Solid Dispersion of Naringenin Prepared Using Hot-Melt Extrusion

Naringenin (NRG) is a plant-derived flavonoid. Due to its antioxidant, anti-inflammatory, and analgesic activities it is beneficial to human health and is often used as a functional food ingredient; however, it has poor water solubility and low in vivo bioavailability. Therefore, the efficacy of NRG can be improved by enhancing its water solubility to increase gastrointestinal absorption. Conventional methods for the formulation of NRG are very complex and use toxic organic solvents, making them impractical for the production of functional foods. The objective of this study was to develop a safe and effective NRG-based functional food material. Previously, we established a technology to prepare amorphous solid dispersions (SDs) from functional food ingredients with poor water solubility and used hot-melt extrusion technology that is comparatively simple and does not involve the use of organic solvents. In this study, we prepared NRG SD and evaluated them both physicochemically and biochemically. NRG SD had superior water solubility and gastrointestinal absorption relative to native NRG and showed higher analgesic efficacy in rats than crystalline NRG. NRG SD was administered to mice in a mixed diet for 28 days, and organ weights and hematological/clinical biochemical parameters were assessed. NRG SD did not demonstrate severe adverse effects. The results suggest that NRG SD is a safe and highly efficacious formulation that can be used as a functional food material in the future.

Poly (Lactic-Co-Glycolic) Acid–Poly (Vinyl Pyrrolidone) Hybrid Nanoparticles to Improve the Efficiency of Oral Delivery of β-Carotene

The aim of this study was to develop a nanoparticle formulation made of poly (vinyl pyrrolidone) (PVP) and poly (lactic-co-glycolic) acid (PLGA) for the oral delivery of β-carotene (BC). The hybrid nanoparticles were prepared by the interfacial deposition method, and the physicochemical properties of this formulation were characterized in terms of its morphology, particle size, size distribution, encapsulation efficiency, dissolution, intestinal permeability, and in vivo pharmacokinetics. Our results demonstrated that BC-loaded nanoformulation and PLGA nanoparticles (PNP) significantly enhanced a release 6.1 times higher than BC suspension. The fortification of PVP into PLGA nanoparticles, named PLGA–PVP hybrid nanoparticles (PPNP), significantly reduced the particle size, as well as led to an increase 1.9 times higher in the in vitro release of BC, compared with PNP. For the ex vivo intestinal permeability assessment, PNP and PPNP–K15 significantly enhanced the intestinal permeability by 2.7 and 6.5 times at the jejunum, and 2.3 and 4.5 times at the ileum, when compared with unformulated BC. According to the pharmacokinetic study, the optimized hybrid formulation significantly increased the peak plasma concentration (C_max) and the area under the curve (AUC_0-t), and the oral relative bioavailability showed a five-fold enhancement compared with that of the BC suspension. Our results indicate that the hybrid nanoparticulate delivery system is an efficient strategy for the oral delivery of BC.

Examination of dissolution ratio of β-carotene in water for practical application of β-carotene amorphous solid dispersion

β-Carotene (BC) has an antioxidant effect that removes active oxygen in vivo and can reduce the risk of developing various diseases, but it is almost insoluble in water. Therefore, to develop highly effective BC functional food products, it is essential to increase its water solubility, which in turn can improve its absolute bioavailability. Recently, a BC amorphous solid dispersion (BC-SD) prepared using hot melt extruder technology had increased water solubility and improved absorption from the gastrointestinal tract. However, only a part of the BC in BC-SD could be dissolved in water. In this study, we evaluated whether the dissolution ratio of BC in water could be improved by examining the mixing ratio of BC and base materials in BC-SD. Results showed that by reducing the mixing ratio of BC to the base materials, the dissolution ratio of BC in water increased. It was also found that when BC-SD, which has the highest dissolution ratio, was intragastrically administered to rats, its absolute bioavailability was most increased. These results are useful findings that may help in reducing the costs associated with the BC-SD manufacturing process and will be an important part of our strategy for practical use in the future.

Carotenoids in Cancer Apoptosis-The Road from Bench to Bedside and Back

An incidence and mortality of cancer are rapidly growing worldwide, especially due to heterogeneous character of the disease that is associated with irreversible impairment of cellular homeostasis and function. Targeting apoptosis, one of cancer hallmarks, represents a potent cancer treatment strategy. Carotenoids are phytochemicals represented by carotenes, xanthophylls, and derived compounds such as apocarotenoids that demonstrate a broad spectrum of anti-cancer effects involving pro-apoptotic signaling through extrinsic and intrinsic pathways. As demonstrated in preclinical oncology research, the apoptotic modulation is performed at post-genomic levels. Further, carotenoids demonstrate additive/synergistic action in combination with conventional oncostatic agents. In addition, a sensitization of tumor cells to anti-cancer conventional treatment can be achieved by carotenoids. The disadvantage of anti-cancer application of carotenoids is associated with their low solubility and, therefore, poor bioavailability. However, this deficiency can be improved by using nanotechnological approaches, solid dispersions, microemulsions or biofortification that significantly increase the anti-cancer and pro-apoptotic efficacy of carotenoids. Only limited number of studies dealing with apoptotic potential of carotenoids has been published in clinical sphere. Pro-apoptotic effects of carotenoids should be beneficial for individuals at high risk of cancer development. The article considers the utility of carotenoids in the framework of 3P medicine.

Effect of dispersed form on the bioavailability of β-carotene from daily intake in humans

In a randomized double-blind crossover study, a canned beverage was prepared using an emulsion dispersion formulation (EM) of β-carotene and a crystal dispersion formulation (CR) of β-carotene; the beverages were ingested by human subjects daily for 2 weeks to compare the β-carotene bioavailability. EM-β-carotene enhanced the β-carotene concentrations in human plasma approximately 4-fold, but CR-β-carotene showed no statistically significant enhancement. Bioaccessibility is the ratio of the solubilized fraction to the whole amount ingested. Bioaccessibility of β-carotene from EM-β-carotene was higher than that from CR-β-carotene in an in vitro digestion test. Contrarily, β-carotene from CR-β-carotene, consists of all-trans-β-carotene, was higher than that from EM-β-carotene, consists of a mixture of cis and all-trans-β-carotene, on the uptake by intestinal Caco-2 cells, suggesting that bioaccessibility was a critical factor in β-carotene bioavailability in this study. EM-β-carotene thus has potential as a food coloring agent with value added because it enhances β-carotene bioavailability.