Ghislain Garrait

Efficacy of mucoadhesive hydrogel microparticles of whey protein and alginate for oral insulin delivery.

ABSTRACTPurposeTo evaluate the efficacy of mucoadhesive insulin-loaded whey protein (WP) /alginate (ALG) microparticles (MP) for oral insulin administration.MethodsInsulin-loaded microparticles (ins-MP) made of whey protein and alginate were prepared by a cold gelation technique and an adsorption method, without adjunction of organic solvent in order to develop a biocompatible vehicle for oral administration of insulin. In vitro characterization, evaluations of ins-MP in excised intestinal tissues and hypoglycaemic effects after intestinal administration in healthy rats were performedResultsThe release properties and swelling behaviors, investigated in different pH buffers, demonstrated a release based on diffusion mechanism following matrix swelling. Mucoadhesion studies in rabbits and insulin transport experiments with excised intestinal rat tissues revealed that encapsulation in microparticles with mucoadhesive properties promotes insulin absorption across duodenal membranes and bioactivity protection. In vivo experiments reinforced the interest of encapsulation in whey protein/alginate combination. Confocal microscopic observations associated with blood glucose levels bring to light duodenal absorption of insulin biologically active following in vivo administration.ConclusionsInsulin-loaded WP/ALG MP with high quantities of drug entrapped, in vitro matrix swelling and protective effect as well as excellent mucohadesive properties was developped. Improvement of intestinal delivery of insulin and increased in bioavailability were recorded.

Self-assembly of β-lactoglobulin and egg white lysozyme as a potential carrier for nutraceuticals.

Self-assembly structures of β-lactoglobulin (βlg) and egg protein lysozyme (Lyso) were developed, using electrostatic interactions between the two oppositely charged proteins. Different βlg/Lyso concentration ratios were essayed at pH 6.8 to select the optimal ratio for the proteins co-precipitation, which behaviour was then studied at varying pH values. Optimal βlg/Lyso concentration ratio, prepared at pH 7.5, was selected for protein co-precipitation. As a result, a structure with a mean diameter of 7.1±2.5 μm was formed, as indicated by static light scattering. Furthermore, the SEM images showed that βlg and Lyso self-assembled to form a microsphere. Vitamin D3, used as a model nutraceutical, was successfully entrapped in the βlg/Lyso microspheres with an encapsulation efficiency of 90.8±4.8%. Therefore, the βlg/Lyso microspheres can serve as a potential food-grade vehicle for bioactives in the formulation of food products and pharmaceuticals.

Increased stability and protease resistance of the β-lactoglobulin/vitamin D3 complex

The stability of the β-lactoglobulin (βlg)/vitamin D3 (D3) complex at 4°C and upon exposure to UV-C light, and in simulated intestinal fluid, were studied in vitro. Caco-2 cells were used to demonstrate the passage of the βlg/D3 complex across the monolayers. Furthermore, an in vivo experiment was conducted by force-feeding rats with the free D3 and βlg/D3 complex, with subsequent determination of the plasma concentration of 25-hydroxy-D3. The βlg/D3 complex significantly improved the stability of the vitamin at 4 °C and when exposed to UV-C light. The resistance of βlg to proteases was increased, indicating a mutual protective effect. The βlg/D3 complex crossed the monolayers, which was confirmed by the significant increase in the concentration of 25-hydroxy-D3 in rats fed the βlg/D3 complex compared to the ones fed the free D3. Therefore, the current study suggests that the βlg/D3 complex can effectively be used for the fortification of milk products and low-fat content foods to improve the intake and bioavailability of D3.

Whey protein and alginate hydrogel microparticles for insulin intestinal absorption: evaluation of permeability enhancement properties on Caco-2 cells.

The evaluation of encapsulated insulin intestinal absorption enhancement was investigated by in vitro methods. Insulin-loaded microparticles (INS-MP) made of whey protein (WP) and alginate (ALG) were prepared by a cold gelation technique. Effect of INS encapsulation toward trypsin and chymotrypsin degradation was performed. Permeability studies using in vitro (Caco-2 cells) experiments were conducted. INS was partially protected by encapsulation toward enzymatic degradation. Moreover INS transport experiments showed that WP and, in lesser extent, ALG were able to enhance INS absorption both as MP and as polymeric solutions by opening the tight junctions. These experiments reinforced the interest of encapsulation in WP/ALG hydrogel combination.

Food protein-based microspheres for increased uptake of vitamin D3.

To protect vitamin D3 during cold storage and exposure to UV-light, vitamin D3 has been entrapped in microspheres formed by bovine protein β-lactoglobulin (βlg) and lysozyme (Lyso) from egg white. The behaviour of the βlg/Lyso microspheres in simulated intestinal fluid and their impact on the kinetic release of D3 were determined. The impact of the D3-loaded βlg/Lyso microspheres on the bioavailability of D3 was evaluated in vivo by force-feeding rats. The data indicate that the βlg/Lyso microspheres effectively improved the stability of D3, which was readily released in the intestines. The release kinetics were accelerated in the presence of proteolytic enzymes. The bioavailability of D3 was improved, as confirmed by the significant increase in the serum levels of 25-hydroxy-D3 in rats. The current work demonstrates that water soluble proteins were used to substantially increase the bioavailability of the lipophilic vitamin, and thus can serve in the oral delivery of D3.

Development of a novel drug delivery system: chitosan nanoparticles entrapped in alginate microparticles

Abstract A novel carrier using chitosan nanoparticles entrapped into alginate microparticles is proposed for protecting molecules of interest from degradation in the digestive tract. The effects of polymer concentration, sonication, stirring, pH, and processing conditions on the physical characteristics of the carrier were studied. FITC and RBITC were used to localise the polymers within particles using CLSM. Diffusion of amaranth red (AR) from nanoparticles was quantified during dissolution under gastric and intestinal conditions. Under optimal preparation conditions, the size distribution of nanoparticles loaded with AR was uniform (690 nm) with an encapsulation efficacy of 21.9%. Alginate microparticles (285 µm) containing a homogenous distribution of nanoparticles and polymers were obtained. At gastric pH, the carrier released less than 5% of the loaded AR and, at intestinal pH, the release was rapid and complete. The drug carriers developed shows a promising use as a vehicle suitable to protect molecules of interest after oral administration.

Improved bioavailability of vitamin D3 using a β-lactoglobulin-based coagulum

Vitamin D3 (D3) was encapsulated within a water-soluble matrix, formed by promoting the βlg/D3 complex by acidification. The capacity of the βlg-based coagulum to increase the long term stability of D3 in cold storage, upon exposure to intensive UV-light, and in the presence and absence of intestinal proteases, was evaluated. Additionally, the impact of the sequestration of D3 within the matrix of βlg-based coagulum on its bioavailability was determined in vivo with force-fed rats. The water solubility, long-term storage and UV-light stability of D3 were significantly increased (p < 0.0001) due to the high encapsulation efficiency (94.5 ± 1.8%). The βlg-based coagulum was not rapidly disrupted by the proteases in the intestines, leading to a slow release of D3, increased uptake of D3 and subsequent enhancement of the bioavailability of D3 in rats.

Development and validation of a new dynamic computer-controlled model of the human stomach and small intestine.

For ethical, regulatory, and economic reasons, in vitro human digestion models are increasingly used as an alternative to in vivo assays. This study aims to present the new Engineered Stomach and small INtestine (ESIN) model and its validation for pharmaceutical applications. This dynamic computer‐controlled system reproduces, according to in vivo data, the complex physiology of the human stomach and small intestine, including pH, transit times, chyme mixing, digestive secretions, and passive absorption of digestion products. Its innovative design allows a progressive meal intake and the differential gastric emptying of solids and liquids. The pharmaceutical behavior of two model drugs (paracetamol immediate release form and theophylline sustained release tablet) was studied in ESIN during liquid digestion. The results were compared to those found with a classical compendial method (paddle apparatus) and in human volunteers. Paracetamol and theophylline tablets showed similar absorption profiles in ESIN and in healthy subjects. For theophylline, a level A in vitro–in vivo correlation could be established between the results obtained in ESIN and in humans. Interestingly, using a pharmaceutical basket, the swelling and erosion of the theophylline sustained release form was followed during transit throughout ESIN. ESIN emerges as a relevant tool for pharmaceutical studies but once further validated may find many other applications in nutritional, toxicological, and microbiological fields. Biotechnol. Bioeng. 2016;113: 1325–1335.

Whey protein mucoadhesive properties for oral drug delivery: Mucin-whey protein interaction and mucoadhesive bond strength.

Whey protein is a natural polymer recently used as an excipient in buccoadhesive tablets but its mucoadhesive properties were barely studied. In this work, we characterize mucoadhesion of whey protein in order to determine the mechanisms and optimal conditions for use as excipient in oral drug delivery. Thus, native and denatured whey protein (NWP and DWP) were investigated and the effect of concentration and pH were also studied. Many methods of characterization were selected to allow the study of chemical and physical interactions with mucin and then the results were bound with an ex vivo experiments. Turbidity of WP-mucin mixture increased at acidic pH 1.2 till 4.5 indicating interaction with mucin but not at pH 6.8. No interaction with mucin was also found by ITC method at pH 6.8 for native and denatured whey protein used at 1% (w/w). Forces of bioadhesion evaluated by viscosity measurements were the best for high concentrated (10.8%) DWP solutions at pH 6.8 and were low at pH 1.2 for NWP and DWP solutions. Addition of chemical blockers indicated that hydrogen bondings and disulfide bridges were the main mechanisms of interactions with mucin. Reticulation of DWP with calcium ions to obtain microparticles (MP) did not influence the ability of interaction with mucin as shown by FTIR analysis. These results correlated with ex vivo study on rat tissue demonstrating important adhesion (75%) of WP MP on the intestine and null on the stomach after 2h of deposit.

A prebiotic matrix for encapsulation of probiotics: physicochemical and microbiological study

Abstract This work aims to develop an encapsulated oral-synbiotic supplement by studying the effect of adding inulin in alginate beads and observing its ability to protect three probiotic strains: Pediocucus acidilactici, Lactobacillus reuteri and Lactobacillus salivarius. Beads of different inulin concentrations 0%, 5%, 10%, 15% and 20% (w/v) in 2% (w/v) alginate solution were prepared by the extrusion/ionotropic gelation method. Polymer distribution within beads was characterised using confocal laser scanning microscopy. Interactions between alginate and inulin were monitored by Fourier transform infra-red spectroscopy (FTIR). Effect of encapsulation on viability, antimicrobial ability, acid tolerance and bile tolerance of probiotic strains were investigated. Antimicrobial and probiotic properties of bacterial strains were not affected by encapsulation. Bacterial protection against acidity was increased by adding inulin. Beads with 5% w/v inulin were the most effective in bacterial protection against bile-salts. To our knowledge, this work is the first to use such high concentrations of inulin.