Development and evaluation of a novel alginate-based in situ gelling system to modulate the release of anthocyanins

Effects of secondary cross-linking on the physicochemical properties of sodium alginate-hydrogel and in vitro release of anthocyanins

To enhance the physicochemical properties and extend the release duration of sodium alginate (SA) hydrogels, this study explored the impact of acidifier type and the number of cross-linking on the physicochemical characteristics and in vitro anthocyanin release from SA hydrogels, utilizing calcium carbonate as the cross-linking agent. The findings revealed that the utilization of gluconolactone (GDL) as an acidifying agent in the preparation of SA hydrogels, as opposed to hydrochloric acid, resulted in a deceleration of the hydrolysis process of calcium carbonate. This deceleration led to the strengthening of hydrogen-bonding interactions and the development of a more compact network structure within the SA hydrogels. Consequently, there was a noticeable enhancement in the hardness, relaxation time, and anthocyanin encapsulation efficiency of the gels. Additionally, the release of anthocyanins in simulated intestinal fluid was delayed. Secondary cross-linking was found to facilitate ionic interactions between SA and Ca2+, further intensifying the denseness of the network structure and enhancing the physicochemical characteristics of the SA hydrogels. Overall, SA hydrogels processed with GDL as the acidifier and subjected to secondary cross-linking exhibited improved physicochemical properties, delayed release effects, and proved to be an efficient system for the delayed release of anthocyanins.

Development and evaluation of anti-reflux functional-oral suspension raft composed of sodium alginate-mung bean protein complex

This study aimed to develop a sodium alginate (Na alginate) and mung bean protein (MBP) raft complex to improve gastric reflux symptoms. Na alginate and MBP complexes with different ratios (1:1, 2:1, and 3:1, respectively) were used for raft formulations through a wet Maillard reaction. Structural properties of raft strength, reflux resistance, intrinsic fluorescence emission spectroscopy, and Fourier transform infrared spectroscopy (FTIR) were investigated for rafts. The suspension 1:1 Na alginate/MBP with 0 h Maillard reaction time exhibited the lowest sedimentation volume among the suspensions. In contrast, 3:1 Na alginate/MBP with 6 h Maillard reaction time showed the highest sedimentation volume. Based on the results, the 3:1 Na alginate/MBP rafts had the best results, and the results were within acceptable limits. Functional properties, including antioxidant properties, the Helicobacter pylori inhibition assay, the pancreatic lipase inhibition assay, and angiotensin-converting enzyme (ACE) inhibition, were investigated for rafts. The Na alginate/MBP raft has similar characteristics to Gaviscon syrup and can be used for obesity, Helicobacter pylori infection, high blood pressure, and gastric reflux.

Edible Gels with Cranberry Extract: Evaluation of Anthocyanin Release Kinetics

The bioactive compounds found in cranberry fruit are natural antioxidants, and their consumption reduces the risk of diabetes, cardiovascular disease, cancers, and urinary tract infections. Oral gels with cranberry fruit extract are a promising product that can ensure accurate dosage and release of the active compounds and are suitable for people with dysphagia. The aim of this study was to determine the effect of polymeric materials on the dissolution kinetics of cranberry fruit anthocyanins from gel formulations. Gel formulations were prepared using freeze-dried cranberry fruit extract with different gelling excipients: chitosan (G1-G3), sodium carboxymethylcellulose (G4-G6), and sodium carboxymethylcellulose combined with carbomers (G7-G9). The dissolution test showed that the release of anthocyanins from gel formulations G1-G6 and G9 was most intense within the first 10 min, with little change in the anthocyanin content of the acceptor medium afterwards. For the formulations based on carboxymethyl cellulose and carbomers G7 and G8, the amount of anthocyanins released into the acceptor medium gradually increased, which prolonged the release time of the active compounds. The test for the release of anthocyanins from the semi-solid systems through a hydrophilic membrane revealed that within the first hour, the total amount of anthocyanins released from the modeled gel formulations (G1-G9) was within the range of 6.02%-13.50%. The 1% chitosan (G1) gel formulation released the fastest and highest amount of anthocyanins (70% within 6 h). The other formulations showed a slower release of anthocyanins, and after 6 h, the amount of anthocyanins released from formulations G2-G9 was <57%.

Development of Oral In Situ Gelling Liquid Formulations of Garcinia Extract for Treating Obesity

Novel in situ gelling liquid formulations incorporating garcinia extract were developed to achieve prolonged delivery of hydroxycitric acid (HCA), an active compound displaying anti-obesity function, following oral administration. The optimized formulation was composed of sodium alginate (1.5% w/v), hydroxypropyl methylcellulose (HPMC K100) (0.25% w/v), calcium carbonate (1% w/v) and garcinia extract (2% w/v). The formulation displayed rapid gelation in less than a minute on exposure to 0.1 N hydrochloric acid (pH 1.2) and remained afloat for more than 24 h. The formulations were capable of gradually releasing more than 80% of HCA load over 8 h, depending on the composition. The resulting gels exhibited high values of gel strength by texture analysis, suggesting they would offer resistance to breakdown under the action of stomach content movement. The optimized formulation loaded garcinia extract significantly reduced lipid accumulation in 3T3-L1 adipocyte cells and displayed moderate anti-inflammatory activity by inhibiting the production of nitric oxide (NO) in LPS-stimulated RAW 264.7 macrophage cells. These findings demonstrate that oral in situ gelling liquid formulations based on sodium alginate and HPMC K100 offer much potential for sustained delivery of HCA and other anti-obesity compounds.

HPLC-UV method validation for quantification of β-carotene in the development of sustained release supplement formulation containing solid dispersion-floating gel in situ

Despite the health benefits of β-carotene, its activity has been hampered by poor aqueous solubility and low oral bioavailability. Therefore, it is crucial to develop a new approach to overcome these problems. In this study, we developed a dry powder supplement comprising a combination approach of solid dispersion and floating gel in situ of β-carotene to enhance the solubility and achieve sustained release behavior. Here, we validated an HPLC method to quantify β-carotene as per the guidelines from ICH. The analytical method was validated in methanol and Fasted-State Simulated Gastric Fluid (FaSSGF) to determine β-carotene in recovery and in vitro release studies, respectively. A simple HPLC method using Xselect CSH™ C18 column (Waters, 3.0 × 150 mm) with the particle size of 3.5 µm was validated with 100% acetonitrile as the mobile phase. The calibration curves were found to be linear with LLOQ values < 3 ng/mL. Importantly, the method was accurate and precise without a carry over effect and successfully applied to determine the β-carotene concentration in the content analysis of the compound and in vitro drug release from floating gel in situ laden with solid dispersion formulations. The sensitivity of the method obtained here offers a wide potential use in various applications in drug delivery systems.

Combination of copigmentation and encapsulation strategies for the synergistic stabilization of anthocyanins

Copigmentation and encapsulation are the two most commonly used techniques for anthocyanin stabilization. However, each of these techniques by itself suffers from many challenges associated with the simultaneous achievement of color intensification and high stability of anthocyanins. Integrating copigmentation and encapsulation may overcome the limitation of usage of a single technique. This review summarizes the most recent studies and their challenges aiming at combining copigmentation and encapsulation techniques. The effective approaches for encapsulating copigmented anthocyanins are described, including spray/freeze-drying, emulsification, gelation, polyelectrolyte complexation, and their combinations. Other emerging approaches, such as layer-by-layer deposition and ultrasonication, are also reviewed. The physicochemical principles underlying the combined strategies for the fabrication of various delivery systems are discussed. Particular emphasis is directed toward the synergistic effects of copigmentation and encapsulation, for example, modulating roles of copigments in the processes of gelation and complexation. Finally, some of the major challenges and opportunities for future studies are highlighted. The trend of integrating copigmentation and encapsulation has been just started to develop. The information in this review should facilitate the exploration of the combination of multistrategy and the fabrication of robust delivery systems for copigmented anthocyanins.

Polysaccharide dual coating of yeast capsules for stabilization of anthocyanins

The dual coated yeast capsules for anthocyanin encapsulation and stabilization were fabricated. Anthocyanins were preloaded in hollow yeast capsules, and then the dual coating was performed by deposition of opposite charged polysaccharides using layer-by-layer technique. The combination of positively charged chitosan and negatively charged chondroitin sulfate was found to confer the yeast capsules with the highest encapsulation efficiency and retention rate of anthocyanins. Additionally, the coated yeast capsules featured high tolerance to environmental stresses (i.e., oxygen, ascorbic acid, and heat) and therefore effectively inhibited the degradation of anthocyanins. These stabilizing effects were related to the formation of high penetration barrier provided by the double layers of polysaccharides, as well as the enhanced hydrophobic microenvironment in the capsules. Further development of the polysaccharide-coated yeast capsules may hold promise for the controlled delivery of other water-soluble bioactive components.

Impact of Alginate Mannuronic-Guluronic Acid Contents and pH on Protein Binding Capacity and Complex Size

Alginates, serving as hydrocolloids in the food and pharma industries, form particles at pH < 4.5 with positively charged proteins, such as β-lactoglobulin (β-Lg). Alginates are linear anionic polysaccharides composed of 1,4-linked β-d-mannuronate (M) and α-l-guluronate (G) residues. The impact of M and G contents and pH is investigated to correlate with the formation and size of β-Lg alginate complexes under relevant ionic strength. It is concluded, using three alginates of M/G ratios 0.6, 1.1, and 1.8 and similar molecular mass, that β-Lg binding capacity is higher at pH 4.0 than at pH 2.65 and for high M content. By contrast, the largest particles are obtained at pH 2.65 and with high G content. At pH 4.0 and 2.65, the stoichiometry was 28-48 and 3-10 β-Lg molecules bound per alginate, respectively, increasing with higher M content. The findings will contribute to the design of formation of the desired alginate-protein particles in the acidic pH range.

Anthocyanins: New techniques and challenges in microencapsulation

Anthocyanins are a bioactive compound belonging to the flavonoid classthatis present in human nutrition through plant-based foods. Due to their antioxidant properties, several health benefits related to their consumption are reported in the literature. The stability of the color and the properties of anthocyanins is strongly affected by pH, solvent, temperature, and other environmental conditions. In addition, the insufficient residence time of anthocyanins in the upper digestive tract causes apartialabsorption, which needs to be improved. These factshave led researchers to investigate new forms of processing that provide minimal degradation. Microencapsulation is a promising possibility to stabilize anthocyanin extracts and allow their addition to food products in a more stable form. The microcapsules can still provide a prolonged gastrointestinal retention time caused by the improvement of the bioadhesive properties in the mucus covering the intestinal epithelium. Although there are efficient and emerging techniques, anthocyanins microencapsulation is still a challenge for the food industry. The purpose of this work is to provide an overview of anthocyanins structure, absorptionand protection, and to show the main conventional and emerging microencapsulation methods and their pros and cons.

Exosomal formulation of anthocyanidins against multiple cancer types

Over the last two decades, berries and berry bioactives, particularly anthocyanins and their aglycones anthocyanidins (Anthos) have demonstrated excellent anti-oxidant, anti-proliferative, apoptotic and anti-inflammatory properties. However, their physicochemical and pharmacokinetic limitations such as, low permeability, and poor oral bioavailability are considered as unfavorable properties for development as drugs. Therefore there is a need to develop systems for efficient systemic delivery and robust bioavailability. In this study we prepared nano-formulation of bilberry-derived Anthos using exosomes harvested from raw bovine milk. Exosomal formulation of Anthos enhanced antiproliferative and anti-inflammatory effects compared with the free Anthos against various cancer cells in vitro. Our data also showed significantly enhanced therapeutic response of exosomal-Anthos formulation compared with the free Anthos against lung cancer tumor xenograft in nude mice. The Anthos showed no signs of gross or systemic toxicity in wild-type mice. Thus, exosomes provide an effective alternative for oral delivery of Anthos that is efficacious, cost-effective, and safe, and this regimen can be developed as a non-toxic, widely applicable therapeutic agent.

Development and evaluation of floating alginate microspheres for oral delivery of anthocyanins - A preliminary investigation

The goal of this study was to develop floating microspheres that could be used as gastroretentive systems for the delivery of anthocyanins (ACNs). These compounds are absorbed in the stomach and small intestine, and insufficient residence time in these organs could result in limited absorption and contribute to degradation. The microparticles containing freeze‐dried haskap berry extract (321.96 ± 8.35 mg cyanidin 3‐glucoside equivalents per g) were prepared by ionotropic gelation of alginate (9%, w/w) with calcium ions (CaCl₂ at 2%, w/v) in the gelation bath, with calcium carbonate as the gas‐generating compound (added at different ratios in the alginate/extract mixture). The effect of acetic acid concentration (2 and 10%, v/v) in the gelation medium was investigated. Increasing the carbonate : alginate weigh ratio from 0 to 3:4 resulted in different degrees of floatability, larger particles, higher encapsulation efficiency, and lower amount of ACN released. The power law equation fitted the experimental data well, indicating that release occurred mainly by diffusion. This is the first time floating microspheres are proposed as gastroretentive platforms for the delivery of ACNs.