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Chitosan nanoparticles loaded with insulin (IN-CS-NPs) were prepared using ionic gelation method using sodium tripolyphophate as a crosslinker. Later the nanoparticles (NPs) were dispersed in buccal films. The physicochemical properties and the morphology of the nanoparticles were characterized. The stability and release of insulin from the NPs were investigated. Buccal films were prepared separately and their properties such as the weight, thickness, pH, and mucoadhesiveness were investigated. The best film was used to disperse IN-CS-NPs and the loaded film was characterized. The nanoparticles size, polydispersity index, zeta potential, entrapment efficacy, and the loading capacity were 325.07 ± 1.32 nm, 0.38 ± 0.03 and 8.41 ± 0.80 mV, and 73.27 and 18.03%, respectively. The weight and thickness of the loaded film with IN-CS-NPs were 23.0 ± 3.0 mg and 0.32 ± 0.04 mm, respectively and the mucoadhesive force was 2.3 ± 0.2 N. The drug was stable in the NPs and in the films for three months, and its release was controlled by the film and the nanoparticles. Finally, the films loaded with IN-CS-NPs were studied in vivo and were compared to the commercially available insulin. The films prepared in this work were found to decrease glucose level significantly in diabetic rats. [ABSTRACT FROM AUTHOR]

The objective of the present study was to prepare and evaluate microspheres for the controlled release of Zidovudine from the prepared microspheres using different polymers. The microspheres were prepared by ionic gelation method. The prepared microspheres were characterized for FTIR, scanning electron microscopy (SEM), the percentage drug content, entrapment efficiency, and in vitro dissolution studies. Accelerated stability studies were also carried out for the formulations. The microspheres were spherical in shape and free flowing. The entrapment efficiency was varying from 76 to 86%. The release of drug from the microspheres was extended up to 8 to 12 hours. FTIR studies showed the stable character of Zidovudine in the microspheres. SEM studies revealed that the microspheres were porous in nature. The release kinetics studies revealed that the prepared microspheres were best fitted to the zero order for all eight formulations and peppa's model. The release kinetics data and characterization studies indicated that the drug release from microspheres was diffusion - controlled and the microspheres were stable in nature. [ABSTRACT FROM AUTHOR]

Encapsulation techniques can protect active components from degradation during storage while maintaining their functionality. The purpose of this study was to evaluate the use of double emulsion followed by ionic gelation in the encapsulation of the extract of Hibiscus sabdariffa L. anthocyanin (HE) in the application of the microparticles in a yogurt food matrix. The ionic gelation methods used were dripping-extrusion—D (Encapsulator Büchi B-390)—and atomization—A (Spray Dryer Büchi B-290). Double emulsion (HE/rapeseed oil/pectin) and a cross-linked solution (CaCl2) were employed. Yogurt matrix was characterized for total dry matter, total lipids, protein content, total lactic bacteria, pH/acidity, phenolic compounds (Folin-Ciocalteu), total anthocyanins (differential pH), antioxidant activity (DPPH), color (colorimeter), and morphology (optical microscopy) and was subjected to a sensory appearance acceptability test (80 panelists). The samples were stored in the absence of light (5 ± 1 °C) and monitored every 7 days for total polyphenols, total anthocyanins, color, pH/acidity, and syneresis, for a period of at least 30 days. The use of microparticles obtained by double emulsion followed by ionic gelation and incorporated in yogurt matrix presented technical feasibility, providing color and functionality to the product. The yogurt matrix with microparticles obtained by the atomization technique presented high acceptability of appearance. Microparticles obtained by the dripping-extrusion technique showed greater stability of anthocyanins (48%) and color (ΔE = 1.42) during the yogurt matrix shelf life. [ABSTRACT FROM AUTHOR]

Nanoparticles of chitosan–tripolyphosphate through two ionic gelation methods (Np1 and Np2) with different dosages of TPP and stirring time were prepared and characterized (FTIR, TEM, SEM–EDS, AFM, XRD, DLS and BET) for the removal of an allura red dye. Np1 and Np2 were obtained with a diameter size of 315.5 nm and 437.4 nm, respectively, both with low polydispersity. The influence on smaller particle size was defined by a low concentration of chitosan solution (0.2 mg/mL) and a higher dosage of TPP (1 mg/mL), while the stirring time did not affect the particle size. Dye removal was placed in batch mode by varying adsorbent dosage, time and pH. The removal percentage (R%) in Np1 decreased with an increase in adsorbent dosage at pH 4 and 6, while Np2 remained constant at pH 2, 4 and 6. Adsorption essays in Np1 and Np2 revealed that under pH 2, an adsorbent dosage of 0.01 g and a contact time of 5 min, the adsorptions are complete. Np2 was recognized as the best adsorbent in comparison with Np1 due to the highest R% under several pHs. This research has demonstrated that the obtained nanoparticles by ionic gelation are suitable for removal of azo dyes in water. [ABSTRACT FROM AUTHOR]

Citrus pectin hydrolysates (Citrus paradisi [Mafc.]) from "Foster," "Red Shambar," "Tangelo Orlando," and "Citrumelo Swingle" cultivars were obtained by partial chemical hydrolysis and their properties as culture media (sole carbon/nutrient source) and encapsulating agents of Lactobacillus plantarum CIDCA 83114 were evaluated. The concentration of neutral sugars was maximal after 2‐hour hydrolysis. All hydrolysates were rich in glucose >xylose >galactose >galacturonic acid >mannose >arabinose. "Citrumelo Swingle" cultivar was the one with the highest concentration of xylose. After 24 hr of fermentation with L. plantarum CIDCA 83114, bacterial viability increased from 6.76 ± 0.14 to almost 9 log CFU/mL, and lactic acid concentration, from 2.63 ± 0.41 to 7.82 ± 0.15 mmol/L in all hydrolysates. Afterwards, bacteria were entrapped in pectate‐calcium beads by ionotropic gelation. Bacterial viability did not significantly decrease after freeze‐drying and storage the beads at 4 °C for 45 days. Practical Application: Pectin hydrolysates were adequate culture media for microorganisms, as determined by the viabililty and lactic acid production. Considering that citrus peels are agro‐wastes obtained in large quantities, their use as encapsulating materials provides a solution to overcome the environmental problem they entail. [ABSTRACT FROM AUTHOR]

The sacha inchi oil (SIO) has about 82% polyunsaturated fatty acids and micronutrients, as tocopherol and phenolic compounds. This work investigated the combination of encapsulation techniques (emulsification and ionic gelation) in order to produce food ingredients with SIO to the enrichment of foodstuffs, as well as to promote its protection against lipid oxidation. For the SIO encapsulation processes, sodium alginate and nonionic surfactants (TWeen 20 and 80) were used as encapsulating/gelation and stabilizers agents, respectively. Emulsions exhibited high electronegativity (≈ -8 0 mV) and pseudoplastic behavior. Control emulsions showed low kinetics stability with increased oil concentration. With polysorbates addition, an increase in the stability of these emulsions and a significant decline in droplet size, span and electronegativity values were observed. Systems with 1.0 wt% TWeen 20 were preferred for particles formation due to the low presence of drops agglomerates. The wet Ca (II) - alginate beads showed characteristic results of ionic gelation technique for moisture content (>85 ± 1%) and water activity (>0.996 ± 0.001), with size ranging from 407 ± 11 to 448 ± 33 µm and high encapsulation efficiency (>99%). The combination of encapsulation methods allowed the improvement of oxidative stability of SIO from 132 ± 9 meq O2. kg-1 to values lower than 44 ± 18meq O2, kg-1. [ABSTRACT FROM AUTHOR]

Microparticles containing anthocyanin extract from Hibiscus sabdariffa L. (HE) were produced by the ionic gelation method by dripping-extrusion (D) and atomization (A). Double emulsion (HE/rapeseed oil/pectin) and a cross-linked solution (CaCl 2) were used. The purpose of the study was to evaluate the release profile of anthocyanins under simulated gastrointestinal conditions, as well as microparticles application in pectin candy. Microparticles were incubated in simulated gastric and intestinal fluids and the release was evaluated by polyphenols, anthocyanin and color. Jelly candies were characterized and being tested for sensory acceptance (84 tasters). Samples were stored in the absence of light (25 °C/55% humidity) and evaluated for polyphenols, anthocyanin and color for 62-days. Microencapsulation of hibiscus anthocyanin resulted in improved enteric protection of bioactive compound, mainly in microparticles generated by dripping-extrusion. Application in jelly candy has shown to be technically feasible, with retention of up to 73% of bioactive compounds and mean sensorial acceptance of 70% tasters. Unlabelled Image • Encapsulation by ionic gelation reduced the release of anthocyanin in simulated gastric fluid. • Encapsulated hibiscus extract application in jelly candies showed technical feasibility. • Jelly candies containing particles obtained by atomization were highly (above 70%) accepted by tasters. • Particles presented good thermal resistance maintaining their integrity after contact with the jelly mass. • Jelly candies with microparticles exhibited anthocyanin retention of 73% after 62 days of storage. [ABSTRACT FROM AUTHOR]

Objective: Control the release and enhance the bioavailability of chitosan-doxazosin mesylate nanoparticles (DM-NPs). Significance: Improve DM bioavailability for the treatment of benign prostatic hyperplasia and hypertension. Methods: Plackett–Burman design was utilized to screen the variables affecting the quality of DM-NPs prepared by ionic gelation method. The investigated variables were initial drug load (X1), chitosan percentage (X2), tripolyphosphate sodium (TPP) percentage (X3), poloxamer percentage (X4), homogenization speed (X5), homogenization time (X6) and TPP addition rate (X7). The prepared DM-loaded NPs have been fully evaluated for particle size (Y1), Zeta potential (Y2), production yield (Y3), entrapment efficiency (Y4), loading capacity (Y5), initial burst (Y6), and cumulative drug release (Y7). Finally, DM pharmacokinetic has been investigated on healthy albino male rabbits by means of non-compartmental analysis. Results: The combination of variables showed variability of Y1, Y2, and Y3 equal to 122–710 nm, 3.49–23.63 mV, and 47.31–92.96%, respectively. While Y4 and Y5, reached 99.87%, and 8.53%, respectively. The prepared NPs revealed that X2, X3, and X4 are the variables that play the important role in controlling the release behavior of DM from the NPs. The in vivo pharmacokinetic results indicated the enhancement in bioavailability of DM by 7 folds compared to drug suspension and the mean residence time prolonged to 23.72 h compared to 4.7 h of drug suspension. Conclusion: The study proved that controlling the release of DM from NPs enhance its bioavailability and improve the compliance of patients with hypertension or benign prostatic hyperplasia. [ABSTRACT FROM AUTHOR]

Abstract This work aimed at producing nanoparticles (NPs) based on thiol-functionalized chitosan (CS) using capillary microfluidic (MF) device combined with ionic gelation method to adsorb mercury ion [Hg (II)] from aqueous solutions. In this line, CS was functionalized with epichlorohydrin/cysteaminium chloride (2.73 M ratio) followed by fabricating NPs via MF and bulk mixing (BM) methods. To characterize the morphology, zeta potential, functionality, structure, and magnetic property of the samples, a series of tests such as SEM, TEM, DLS, FTIR, XRD, and VSM were carried out, respectively. The obtained results showed that MF technique was able to produce NPs with a diameter as small as 18 ± 3 nm, and a uniform shape compared to BM method. Thiol groups (−SH) functionalization on CS surface was confirmed by appearing a characteristic peak at 2579 cm−1. Also, the XRD patterns indicated the appropriate synthesis of Fe 3 O 4 (magnetite), and no change in the structure of CS NPs in the presence of magnetite. Moreover, adding the magnetite to thiol-functionalized CS NPs led to suitable saturation magnetization about 26 emu/g to facilitate their separation using a magnetic field. To evaluate the performance of the nanoadsorbent, it has been exposed to Hg (II) in an aqueous solution which in turn the parameters optimization for the adsorption was done via Box-Behnken design (BBD) method, exhibiting the effect of adsorbent dose and the initial concentration of Hg (II) was much more significant than that of pH. Different concentrations of total dissolved solids up to 1000 mg/L had no adverse impact on the adsorption process confirmed by EDAX spectra. The least value of RMSE (5.023) and χ2 (0.3) were observed for Redlich-Peterson, Radke-Prausnitz, and UT isotherms. Maximum adsorption capacities calculated using Langmuir and UT models were 1192 mg/g and 1126 mg/g, respectively. Thermodynamic studies demonstrated that the nature of the adsorption process was spontaneous and endothermic. Recovery of nanoadsorbent was successfully carried out using HCl 0.5 mol/L. The adsorption studies revealed that the prepared nanoadsorbent is promising candidate used in mercury removal from a real wastewater potentially. Graphical abstract Image 1 Highlights • Functionalizing CS with arm active including cysteaminium chloride/epichlorohydrin. • Fabricating thiol-functionalized CS NPs using capillary microfluidic/ionic gelation. • Using the thiol-functionalized CS NPs for Hg (II) adsorption with high efficiency. • Investigating isotherm models along with thermodynamic behavior of the adsorption. • Separating CS plus Fe 3 O 4 NPs using a magnetic field after the Hg (II) adsorption. [ABSTRACT FROM AUTHOR]

To investigate the use of chitosan nanoparticles (CS-TPP-NPs) as carriers for α- and β-arbutin. In this study, CS-TPP-NPs containing α- and β-arbutin were prepared via the ionic cross-linking of CS and TPP and characterized for particle size, zeta potential, and dispersity index. The entrapment efficiency and loading capacity of various β-arbutin concentrations (0.1, 0.2, 0.4, 0.5, and 0.6%) were also investigated. SEM, TEM FTIR, DSC and TGA analyses of the nanoparticles were performed to further characterize the nanoparticles. Finally, stability and release studies were undertaken to ascertain further the suitability of the nanoparticles as a carrier system for α- and β-arbutin. Data obtained clearly indicates the potential for use of CS-TPP-NPs as a carrier for the delivery of α- and β-arbutin. The size obtained for the alpha nanoparticles (α-arbutin CSNPs) ranges from 147 to 274 d.nm, with an increase in size with increasing alpha arbutin concentration. β-arbutin nanoparticles (β-arbutin CSNPs) size range was from 211.1 to 284 dn.m. PdI for all nanoparticles remained between 0.2–0.3 while the zeta potential was between 41.6–52.1 mV. The optimum encapsulation efficiency and loading capacity for 0.4% α-arbutin CSNPs were 71 and 77%, respectively. As for β-arbutin, CSNP optimum encapsulation efficiency and loading capacity for 0.4% concentration were 68 and 74%, respectively. Scanning electron microscopy for α-arbutin CSNPs showed a more spherical shape compared to β-arbutin CSNPs where rod-shaped particles were observed. However, under transmission electron microscopy, the shapes of both α- and β-arbutin CSNP nanoparticles were spherical. The crystal phase identification of the studied samples was carried out using X-ray diffraction (XRD), and the XRD of both α and β-arbutin CSNPs showed to be more crystalline in comparison to their free form. FTIR spectra showed intense characteristic peaks of chitosan appearing at 3438.3 cm−1 (-OH stretching), 2912 cm−1 (-CH stretching), represented 1598.01 cm−1 (-NH2) for both nanoparticles. Stability studies conducted for 90 days revealed that both α- and β-arbutin CSNPs were stable in solution. Finally, release studies of both α- and β-arbutin CSNPs showed a significantly higher percentage release in comparison to α- and β-arbutin in their free form. Chitosan nanoparticles demonstrate considerable promise as a carrier system for α- and β-arbutin, the use of which is anticipated to improve delivery of arbutin through the skin, in order to improve its efficacy as a whitening agent. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Encapsulation of stevia crude extract within two alginate blends by ionic gelation has been assessed. • High encapsulation efficiency of polyphenols was achieved for all stevia-loaded beads. • Size of beads decreased as encapsulation efficiency increased for both the blends. • Metabolomics profiling identified 479 free and encapsulated polyphenolic compounds. • Crosslinking conditions impacted on phenolic profile providing a selective uptake. Abstract We formulated and characterised two alginate blends for the encapsulation of stevia extract (SE) via ionic gelation through an extrusion technique. Calcium chloride in SE and calcium chloride solutions were assessed as crosslinkers to overcome phenolic losses by diffusion and increase encapsulation efficiency (EE). Regardless of the blend, all stevia-loaded beads exhibited high EE (62.7–101.0%). The size of the beads decreased as EE increased. Fourier transform infrared analysis showed increased hydrogen bonding between SE and alginates, confirming the successful incorporation of SE within the matrix. Untargeted metabolomics profiling identified 479 free and encapsulated polyphenolic compounds. Flavonoids (catechin and luteolin equivalents) were predominant in SE whereas tyrosols and 5-pentadecylresorcinol equivalents were predominant in all bead formulations. Three-common discriminant compounds were exclusive to each blend and were inversely affected by the crosslinking conditions. Both alginate blends have been shown to be feasible as carrier systems of stevia extracts independent of crosslinking conditions. [ABSTRACT FROM AUTHOR]

Layered double hydroxides (LDHs) present multiple applications due to their versatility and reactivity. Thus, Ca-Al LDHs with Friedel's salt structure (HC) have been proposed as heavy metal scavengers due to their buffering capacity at basic pHs. Nevertheless, the control of the reactivity of LDHs such as HC is necessary to optimize their applications. Here, the reactivity of an HC prepared by a coprecipitation method was modified by its inclusion in calcium alginate (CaAlg) beads prepared by ionic gelation. The obtained beads (CaAlg/HC) showed good dispersion of the HC particles in the alginate matrix and were used to test the acid base reactivity and heavy metal uptake capacity compared with pure CaAlg beads and HC powder separately. The pH buffering capacity of CaAlg beads was enriched by the inclusion of HC that, in turn, was modulated in its reactivity. Thus, the HC dissolution times changed from mere seconds for the powder to tens of minutes when enclosed in the beads in a kinetic profile determined by the diffusive step. On the other hand, Cu2+ uptake capacity of CaAlg/HC beads combined the Cu(OH)2 precipitation capacity of HC with the complexation capacity of alginate, reaching good affinity and capacity for the obtained beads. Nevertheless, the precipitation of the hydroxide was produced outside the bead, which would induce the addition of an additional separation step to produce an acceptable Cu2+ elimination. [ABSTRACT FROM AUTHOR]

Abstract Since most studies regarding immortelle (Helichrysum italicum) are focused on the properties and composition of its essential oil, the aim of this study was to develop edible films based on immortelle water extract. Alginate and pectin combined with various proteins served as carriers for the formulation of biodegradable films and hydrogel particles. Films with different biopolymers and incorporated hydrogel particles were prepared by casting method and hydrogel particles were produced by ionic gelation. The bioactive profile (the content of total (TPC) and specific polyphenols, hydroxycinnamic acids (HCAC) and antioxidant capacity (AC)) of the developed matrices was characterized using spectrophotometric methods and high performance liquid chromatography (HPLC). Zeta-potential and rheological properties of alginate- and pectin-based film-forming solutions and physico-chemical (color, particle size, film thickness, dry matter content) and sensory properties of the developed particles and films were evaluated. The highest TPC (31.31 mg GAE/g sample) and HCAC (27.20 mg CAE/g sample) as well as the highest AC (0.15 mmol TE/g sample) was determined in pectin-based films. The addition of proteins decreased the content of the examined bioactive parameters, while the addition of hydrogel particles altered their physico-chemical properties. The obtained results indicate a great application potential of the developed biodegradable matrices. Highlights • Immortelle extract is abundant in polyphenols, resulting in high bioactivity. • Chlorogenic acid derivatives dominate the bioactive profile of immortelle films. • The addition of hydrogels significantly enriched the bioactive profile of the films. • Polyphenols entrapped in films with hydrogels exhibit a prolonged release in SGF. • Alginate-based films have more desirable sensory properties than the pectin-ones. [ABSTRACT FROM AUTHOR]

The possibilities of using chitosan and its composites with transition metal oxides for arsenic removal from solutions with low concentrations are discussed. Methods for the formation of composite sorbents based on chitosan and molybdenum in a composition with a carbon fiber providing improved physical and chemical properties with respect to the recovered component are considered. The sorption properties of the obtained materials under dynamic conditions for the purification of solutions from arsenic are compared. It is shown that the preliminary modification of the carbon fiber with chitosan by ionic gelation using sulfate ion and then by adsorption with molybdate ion leads to the production of an efficient sorption material that provides the purification of 1600 column volumes of an arsenic solution at an initial concentration of 105 μg L–1 to a maximum permissible concentration of 50 μg L–1. The calculation methods show that the gel ability of sulfate and molybdate ions is approximately the same. [ABSTRACT FROM AUTHOR]

To improve the efficacy of existing classes of antibiotics (ciprofloxacin), allow dose reduction, and minimize related toxicity, this study was executed because new target-oriented livestock antimicrobials are greatly needed to battle infections caused by multidrug-resistant (MDR) strains. The present study aims to green synthesize a biocompatible nanohybrid of ciprofloxacin (CIP)-Ag/TiO2/chitosan (CS). Silver and titanium nanoparticles were green synthesized using Moringa concanensis leaves extract. The incorporation of silver (Ag) nanoparticles onto the surface of titanium oxide nanoparticles (TiO2NPs) was done by the wet chemical impregnation method, while the encapsulation of chitosan (CS) around Ag/TiO2 conjugated with ciprofloxacin (CIP) was done by the ionic gelation method. The synthesized nanohybrid (CIP-Ag/TiO2/CS) was characterized using standard techniques. The antibacterial potential, killing kinetics, cytotoxicity, drug release profile, and minimum inhibitory concentration (MIC) were determined. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) revealed spherical agglomerated nanoparticles (NPs) of Ag/TiO2 with particle sizes of 47–75 nm, and those of the CIP-Ag/TiO2/CS nanohybrid were in range of 20–80 nm. X-ray diffractometer (XRD) patterns of the hetero system transmitted diffraction peaks of anatase phase of TiO2 and centered cubic metallic Ag crystals. Fourier Transform Infrared spectroscopy (FTIR) confirmed the Ti-O-Ag linkage in the nanohybrid. The zeta potential of CIP-Ag/TiO2/CS nanohybrid was found (67.45 ± 1.8 mV), suggesting stable nanodispersion. The MIC of CIP-Ag/TiO2/CS was 0.0512 μg/mL, which is much lower than the reference value recorded by the global CLSI system (Clinical Laboratory Standards Institute). The CIP-Ag/TiO2/CS nanohybrid was found to be effective against mastitis causing MDR E. coli; killing kinetics showed an excellent reduction of E. coli cells at 6 h of treatment. Flow cytometry further confirmed antibacterial potential by computing 67.87% late apoptosis feature at 6 h of treatment; antibiotic release kinetic revealed a sustained release of CIP. FESEM and TEM confirmed the structural damages in MDR E. coli (multidrug-resistant Escherichia coli). The CIP-Ag/TiO2/CS nanohybrid was found to be biocompatible, as more than 93.08% of bovine mammary gland epithelial cells remained viable. The results provide the biological backing for the development of nanohybrid antibiotics at a lower MIC value to treat infectious diseases of cattle and improve the efficacy of existing classes of antibiotics by conjugation with nanoparticles.

Antimicrobial agent abuse poses a serious threat for future pharmacotherapy, including vaginal administration. The solution can be found in simple polymeric systems with inherent antimicrobial properties without the need to incorporate drugs, for instance alginate beads cross-linked by bivalent ions. The main goal of the presented study was to provide improvement on the well-documented cytotoxicity of Cu2+ cross-linked alginate. Alginate beads were prepared by external ionotropic gelation by cross-linking with Cu2+, Ca2+ and Zn2+ ions, separately and in mixtures. Morphological properties, swelling capacity, ion release and efficacy against the most common vaginal pathogens (C. albicans, E. coli, E. faecalis and virus strain—human herpesvirus type 1) were evaluated. The prepared particles (particle size 1455.68 ± 18.71–1756.31 ± 16.58 µm) had very good sphericity (0.86 ± 0.04–0.97 ± 0.06). In mixture samples, Cu2+ hampered second ion loading, and was also released incompletely (18.75–44.8%) compared to the single ion Cu2+ sample (71.4%). Efficacy against the selected pathogens was confirmed in almost all samples. Although anticipating otherwise, ion mixture samples did not show betterment over a Cu2+ cross-linked sample in cytotoxicity–pathogen efficacy relation. However, the desired improvement was found in a single ion Zn2+ sample whose minimal inhibition concentrations against the pathogens (0.6–6.12 mM) were close to, or in the same mathematical order as, its toxic concentration of 50 (1.891 mM). In summary, these findings combined with alginate’s biocompatibility and biodegradability give the combination solid potential in antimicrobial use.

[Display omitted] • Pomegranate extract (PE) was loaded within pectin-based hydrogel beads. • Mechanical strength was proportional to the total phenolic content of the beads. • Electrostatic coating reduced the diffusivity of PE in water. This study aimed at producing pectin hydrogel beads by ionic gelation proce to carry pomegranate extract (PE) evaluating approaches to increase its retention and protect the polyphenols from environmental conditions that interfere in the stability and color of these compounds, such as the pH of the medium. Several strategies were tested to reduce the mass transfer and consequently increase its retention. The insertion of a filler (gelatinized starch), the employment of different concentrations from the external environment, the adsorption using blank pectin-starch beads, and the electrostatic coating using chitosan were performed. The release of entrapped compounds over time was employed to evaluate the release pattern of PE in water media. Diffusion coefficients calculated from these experiments were then used to estimate the PE release behavior. The encapsulation efficiency (EE) was significantly improved (42 % to 101 %) when equalizing the concentration of the external medium with that from the beads formulation. Furthermore, the increase in the PE concentration was proportional to the rise in the mechanical strength (MS) of the beads which indicates a modification of internal structure due to the presence of polyphenols. The adsorption was efficient in entrapping the active compound, and despite the high PE content observed for all beads (average value of 2960.26 mg of gallic acid equivalent/100 g sample), they had the lowest diffusion coefficient from the release in water media. Finally, the coating was able to reduce the release rate in most of the tests (D AB uncoated = 0.5 D AB coated), however, during the electrostatic deposition a loss of about 32 % of the phenolic compounds in the chitosan solution was observed which led to a reduced EE. Despite the obtention of retarded release, coating studies need to be improved. Some adjustments in the execution of this technique are necessary so that the losses are reduced and the process becomes viable for the use of beads in food. [ABSTRACT FROM AUTHOR]

Co-encapsulation of bioactive compounds with different functionality in a carrier has received considerable attention, while co-encapsulation of bioactives with different solubility remains a challenge. In this study, the co-encapsulation of hydrophilic l -ascorbate and hydrophobic curcumin was achieved using an organic-free method. The aim of this work was to evaluate the efficacy of chitosan coating loaded with l -ascorbate on the complexation of curcumin with caseinate by investigating their interaction, storage stability and release behavior during simulated digestion. The size and ζ-potential of the optimized chitosan-caseinate binary particles at pH 5.0 were 582 nm and 28 mV, respectively. l -ascorbate electrostatically interacted with chitosan and then coated on the caseinate particles where hydrophobic curcumin was encapsulated. The encapsulation efficiency of curcumin and l -ascorbate was 96.2% and 47.6%, respectively. l -ascorbate-loaded chitosan coating significantly improved the storage and irradiation stability of curcumin and inhibited the structural changes of caseinate induced by the loaded curcumin after storage. The antioxidant activity of the co-delivered system was significantly improved compared with either individual system and basically unchanged during irradiation. These results may serve as a helpful guide for future study on the optimization of core-shell particles for the co-delivery of multiple bioactive compounds. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Gellan microgels presented larger sizes than alginate-based microparticles. • The consistency index of the solutions influenced particle sizes during atomization. • Both alginate and gellan microgels exhibited high anthocyanin encapsulation efficiency. • Starch decreased the hardness and elasticity for gellan-based gels. • Corn and phosphated starch strengthened the network for the alginate-based gels. Microgels were tailored by combining starches from different sources (corn, potato or phosphated) and anionic polysaccharides (gellan gum or alginate) using ionic gelation. Rheological analysis pointed out a lower consistency index for alginate-based solutions compared to the gellan-based ones and, therefore, this favored the formation of smaller droplets during the atomization process (58.74 ± 1.72 µm vs. 101.38 ± 2.71 µm). Additionally, it was noticed that the starch granule size is directly related to the diameter of the particle formed, both for gellan and alginate systems. The combination between starches and anionic gums still promoted an increase in the water holding capacity, probably due to the presence of additional hydrophilic groups from starch. According to the mechanical properties, starch acts differently when combined with alginate or gellan gum, considering it strengthened the biopolymeric network for the alginate-based gels increasing the stress at rupture values (except for potato starch), while it decreased the hardness and elasticity for gellan-based gels. Microparticles based on gellan and alginate showed high anthocyanin encapsulation efficiency (EE ≥ 80%) in all systems. In these cases, the addition of starch did not contribute to increasing this property, even though starch granules filled the gel pores. The high EE showed that the studied systems allow the encapsulation of anthocyanin and suggest possible encapsulation of other hydrophilic bioactive compounds, considering the best type of starch for each application. [ABSTRACT FROM AUTHOR]

Background & Aims: In recent years, the feasibility of hydrophilic nanoparticles has been broadly investigated for use in drug delivery and therapeutic systems. Due to the problems of traditional adjuvants, in this study Agkistrodon halys (Ah) Snake venom was loaded in chitosan nanoparticles (CS NPs) in order to be used as an advanced adjuvant and antigen delivery system in antidote production industry. Methods: CS NPs containing Ah venom were prepared using ionic gelation and crosslinker method. In this study, polymer concentration, cross-linker concentration, particles size, particle size distribution, zeta potential, particles shape and surface characteristics, loading efficiency, loading capacity, and particles structure were optimized. Results: Optimum concentration achieved were chitosan 2mg/ml and cross-linker 1mg/ml and Agkistrodon Halys snake venum 500 mg/ml. Mean particle size, polydispersity index (PDI), and zeta potential of of venom-loaded CS NPs were respectively 129 nm, 0.418 and 41 mV. The loading capacity (LC) and loading efficiency (LE) were 82±1.9 and 88±2.1, respectively. Fourier transform infrared spectroscopy of nanoparticles showed between chitosan and crosslinker. An initial burst release and second slow release up to 96 hours was observed. Conclusion: The obtained results suggested that venom-loaded CS NPs could be a suitable alternative to conventional adjuvant for manufacturing antivenom.

Diabetes mellitus is a chronic endocrine disease, affecting more than 400 million people around the world. Patients with poorly controlled blood glucose levels are liable to suffer from life-threatening complications, such as cardiovascular, neuropathy, retinopathy and even premature death. Today, subcutaneous parenteral is still the most common route for insulin therapy. Oral insulin administration is favourable and convenient to the patients. In contrast to injection route, oral insulin delivery mimics the physiological pathway of endogenous insulin secretion. However, oral insulin has poor bioavailability (less than 2%) due to the harsh physiological environment through the gastrointestinal tract (GIT). Over the last few decades, many attempts have been made to achieve an effective oral insulin formulation with high bioavailability using insulin encapsulation into nanoparticles as advanced technology. Various natural polymers have been employed to fabricate nanoparticles as a delivery vehicle for insulin oral administration. Chitosan, a natural polymer, is extensively studied due to the attractive properties, such as biodegradability, biocompatibility, bioactivity, nontoxicity and polycationic nature. Numerous studies were conducted to evaluate chitosan and chitosan derivatives-based nanoparticles capabilities for oral insulin delivery. This review highlights strategies that have been applied in the recent five years to fabricate chitosan/chitosan derivatives-based nanoparticles for oral insulin delivery. A summary of the barriers hurdle insulin absorption rendering its low bioavailability such as physical, chemical and enzymatic barriers are highlighted with an emphasis on the most common methods of chitosan nanoparticles preparation. Nanocarriers are able to improve the absorption of insulin through GIT, deliver insulin to the blood circulation and lower blood glucose levels. In spite of some drawbacks encountered in this technology, chitosan and chitosan derivatives-based nanoparticles are greatly promising entities for oral insulin delivery.

This study aimed to assess the thermal stability of the bioactive compounds from annatto seed extract, encapsulated by ionic gelation using quinoa proteins, lentil proteins, soy proteins, and sodium caseinate as carrying materials. The 10.0% aqueous dispersions of the different proteins (carriers) were prepared and mixed with the annatto seed extract. The dispersions were then extruded into a calcium chloride solution to induce the extract encapsulation. The capsules were characterized by encapsulation efficiency, particle size, infrared transmission spectroscopy, confocal microscopy, and scanning electron microscopy (SEM). The antioxidant and antimicrobial activities, the polyphenol compounds, and bixin content from the free and encapsulated extract were assessed once stored for 12 d at different temperatures (4 °C, 25 °C, and 65 °C). The results demonstrated the ability of the proteins to encapsulate the annatto extract with encapsulation efficiencies ranging from 58% to 80%, where the protein structure and amino acid content were the relevant factors to obtain high encapsulation efficiencies. The free extracts stored at 65 °C for 12 d experienced a degradation of bixin and polyphenol compounds, respectively. Conversely, the encapsulated extract had degradations from ~34.00% to ~4.05% for polyphenol compounds and ~20.0% for bixin, respectively. These proteins have a potential encapsulation capacity of annatto extract by ionic gelation.

The objective of this study was to develop chitosan (CS) nanoparticles (NPs) loaded with deferoxamine mesylate (DFO) for slow release of this iron-chelating drug. Drug nanoencapsulation was performed via ionic gelation of chitosan using sodium tripolyphosphate (TPP) as cross-linker. Nanoparticles with a size ranging between 150 and 400 nm were prepared for neat CS/TPP with a 2/1 molar ratio while their yield was directly dependent on the applied stirring rate during the preparation process. DFO at different content (20, 45 and 75 wt %) was encapsulated into these nanoparticles. We found that drug loading correlates with increasing DFO content while the entrapment efficiency has an opposite behavior due to the high solubility of DFO. Hydrogen-bonding between amino and hydroxyl groups of DFO with reactive groups of CS were detected using FT-IR spectroscopy while X-ray diffraction revealed that DFO was entrapped in amorphous form in the CS nanoparticles. DFO release is directly dependent on the content of loaded drug, while model analysis revealed that the release mechanism of DFO for the CS/TPP nanoparticles is by diffusion. Treatment of murine RAW 264.7 macrophages with nanoencapsulated DFO promoted an increased expression of transferrin receptor 1 (TfR1) mRNA, a typical homeostatic response to iron deficiency. These data provide preliminary evidence for release of pharmacologically active DFO from the chitosan nanoparticles.

Sitagliptin (SGN) is an antidiabetic drug used for treatment of diabetes mellitus type II. The objectives of this study were to formulate SGN in form of thiolated chitosan (TC) nanoparticles to enhance the mucoadhesion properties of SGN to the gastrointestinal tract, prolong drug release, decrease side effects, and enhance patient compliance. Seventeen batches of SGN-TC nanoparticles were designed by Box-Behnken design and prepared using the ionic gelation method using tripolyphosphate (TPP) as crosslinking agent. The prepared formulations were evaluated for particle size, entrapment efficiency %, and in vitro drug release. Based on the results of optimization, three formulations (F1−F3) were prepared with different drug polymer ratios (1:1, 1:2, and 1:3). The mucoadhesion study and in vivo hypoglycemic activity of three formulations were evaluated in comparison to free SGN in streptozotocin (STZ)-induced diabetic rats. The seventeen SGN-TC nanoparticles showed small particle sizes, high entrapment efficiency, and prolonged drug release. The concentration of TC polymers had highest effect on these responses. The percentage of SGN−TC nanoparticles adhered to tissue was increased and the release was prolonged as the concentration of TC polymer increased (F3 > F2 > F1). The hypoglycemic effect of SGN-TC nanoparticles was significantly higher than resulted by free SGN. It was concluded that TC nanoparticles had the ability to enhance the mucoadhesion properties of SGN and prolong the drug release. SGN-TC nanoparticles significantly reduced plasma glucose levels compared to free SGN in STZ-induced diabetic rats.

ABSTRACT: Microencapsulation is used for protection and release of bioactive compounds. Combination of encapsulation methods allows the production of matrices with better technological properties compared to the application of one of the methods alone. Use of ionic gelation produces porous microparticles, and coating it with a protein, by electrostatic interaction, may contribute to a better protection of the active compound. The objective of the research was to produce alginate microparticles (AG) through ionic gelation and to coat them with soluble protein from soy protein concentrate. Two factors were studied, calcium concentration during ionic gelation (0.8, 1.6 and 2.4% w/w) and pH (3.5 and 7.0) of the protein solution for electrostatic interaction. Zeta potential (ZP) of biopolymers and microparticles were determined. Microparticles were characterized according to its morphology, average size and size distribution, as well as protein adsorption. Microparticles presented (154-334μm) multinuclear distribution of active compound, continuous and smooth surface, with a great standard deviation considering average size. The calcium concentration did not influence the protein adsorption on microparticles.The pH used in protein adsorption showed significant effect, with higher adsorption occurring at pH 3.5 (6.5 to 6.7% w/w, dry basis,db, of adsorbed protein) compared to pH 7.0 (pKa AG

The chitosan nanoparticles used widely as a drug delivery systems recently. In the present study the Echis carinataus snake venom loaded chitosan nanoparticles were prepared based on ionic gelation of tripolyphosphate and chitosan. The nanoparticles physicochemical characteristics, stability and biological activity of encapsulated venom were studied. The particles were spherical in shape and the tripolyphosphoric groups of TPP were linked to the ammonium groups of chitosan. Optimum particle size of chitosan and venom loaded nanoparticles were 89 and 116 nm, respectively. Optimum loading capacity and loading efficiency obtained by 500 µg/ml concentration of venom. The biological activity of venom remained intact during nanoparticle formation and showed no considerable reduction in stability analysis. Our results suggested that Chitosan nanoparticles, which prepared in this work possibly, could be used as an alternative for traditional adjuvants.

Naringenin (NAR), a natural flavonoid aglycone of naringin has been extensively investigated for its pharmacological activities, including anti-tumor effects. However, its poor bioavailability has been identified as the single most important challenge in oral drug delivery. Based in this condition, it is used nanoencapsulation to increase the effectiveness of NAR as anti-cancer. The objectives of this research were to develop the formulation of NAR-loaded nanoparticles (NARNPs) as well as to evaluate its potential as anti-cancer against T47D breast cancer cells line. NARNPs is prepared through the method of ionic gelation, meanwhile its characteristic is evaluated through photon correlation spectroscopy (PCS), transmission electron microscopy (TEM), fourier transform infra-red spectroscopy (FTIR), and different scanning calorimeter (DSC). The result of MTT test and cellular uptake indicate that NARNPs increase cytotoxicity and internalization of NAR to the cells compared to that of free NAR. The result of qualitative apoptosis study using fluorescence microscope indicates that both free NAR and NARNPs were able to induce apoptosis. It can be conclude that Chitosan nanoparticles–TPP conjugates have the capability to encapsulate naringenin hence increase the cellular uptake and cytotoxcicity of naringenin against T47D cell line. NARNPs also could induce the apoptosis effect.

Manganese zinc ferrite nanoparticles (MZF NPs) were synthesized by using a direct, efficient and environmental friendly hydrothermal method. To improve the colloidal stability of MZF NPs for biomedical applications, NPs were coated with chitosan by ionic gelation technique using sodium tripolyphosphate (TPP) as crosslinker. The synthesized NPs were characterized by X ray diffraction (XRD) analysis, inductively coupled plasma optical emission spectrometry (ICP-OES), fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) and the dynamic light scattering (DLS) methods. The results confirmed the spinel ferrite phase formation without any calcination process after synthesis. Mean particle size of bare NPs was around 14 nm. Moreover, certain molar ratio of chitosan to TPP was required for encapsulation of NPs in chitosan. Coated NPs showed hydrodynamic size of 300 nm and polydispersity index about 0.3.

The purpose of present study was to optimize rizatriptan (RZT) chitosan (CS) nanoparticles using ionic gelation method by application of quality by design (QbD) approach. Based on risk assessment, effect of three variables, that is CS %, tripolyphosphate % and stirring speed were studied on critical quality attributes (CQAs); particle size and entrapment efficiency. Central composite design (CCD) was implemented for design of experimentation with 20 runs. RZT CS nanoparticles were characterized for particle size, polydispersity index, entrapment efficiency, in-vitro release study, differential scanning calorimetric, X-ray diffraction, scanning electron microscopy (SEM). Based on QbD approach, design space (DS) was optimized with a combination of selected variables with entrapment efficiency > 50% w/w and a particle size between 400 and 600 nm. Validation of model was performed with 3 representative formulations from DS for which standard error of − 0.70-3.29 was observed between experimental and predicted values. In-vitro drug release followed initial burst release 20.26 ± 2.34% in 3-4 h with sustained drug release of 98.43 ± 2.45% in 60 h. Lower magnitude of standard error for CQAs confirms the validation of selected CCD model for optimization of RZT CS nanoparticles. In-vitro drug release followed dual mechanism via, diffusion and polymer erosion. RZT CS nanoparticles were prepared successfully using QbD approach with the understanding of the high risk process and formulation parameters involved and optimized DS with a multifactorial combination of critical parameters to obtain predetermined RZT loaded CS nanoparticle specifications.

Flaxseed oil is a major source of omega-3 polyunsaturated fatty acids (PUFAs), as it contains nearly 50% of alpha-linolenic acid. For this reason it is highly susceptible to auto-oxidation. The aim of the work was to increase the stability of flaxseed oil by a microencapsulation process based on ionic gelation through vibrating-nozzle extrusion technology, using pectin as shell material. Two different drying systems, passive air drying (AD) and fluid bed (FB), were compared. The results show that the encapsulation efficiency is very high (up to 98%). Besides being approximately 20-fold faster, FB gives beads showing on average higher payload (76% vs 68%) and lower peroxide value (9.64 vs 21.33) than the AD. An accelerated test carried out on FB-dried beads shows that the oxidative stability of encapsulated oil is 13-fold higher than bulk oil (PV FB: 20 vs PV oil: 260), demonstrating the protecting effect of microencapsulation. [ABSTRACT FROM AUTHOR]

Purpose: To prepare and characterise doxorubicin nanopatrticles and study their drug delivery in breast cancer. Methods: Doxorubicin nanoparticles were prepared by ionic gelation method using sodium alginate as polymer. The formulations were optimized by cross-linking CaCl2 with sodium alginate at different concentrations. Zeta sizer Nano ZS (UK) was used to determine the mean particle size distribution of the nanoparticle preparations. The shape and external morphologies of the nanoparticles were evaluated by scanning electron microscopy (SEM). Drug release was determined and kinetic release analysis was applied to determine the mechanism of drug release. Results: Entrapment efficiency and mean particle size values were correlated. Scanning electron micrographs showed that the nanoparticles were spherical with little irregularity but without cracks. Doxorubicin release from the sodium alginate nanoparticles followed Korsmeyer-Peppas model which suggest that drug release from the nanoparticles was by diffusion and dissociation from the natural polymer matrix. Conclusion: The doxorubicin-loaded nanoparticles showed concentration-dependent increases in entrapment efficiency. The nanoparticles displayed anticancer properties in breast cancer cell line, thus indicating its potential fo chemotherapeutic application. [ABSTRACT FROM AUTHOR]

Recently, starch nanoparticles (SNPs) have attracted considerable attention and are being widely used in various fields. In this study, we aimed at the development of a new type of SNPs by ionic gelation. Oxidized debranched starch and calcium ions were used to prepare the nanoparticles. Debranched starch was first oxidized with a 2,2,6,6-tetramethylpiperidine-1-oxyl/sodium bromide/sodium hypochlorite (TEMPO-NaBr-NaClO) system. The results showed that at the highest oxidation level, the carboxyl content was 1.224% and the negative charge value was about −30 mV. SNPs were prepared using oxidized debranched starch and different concentrations of calcium ions (0.2, 0.1, and 0.05 M) by ionic gelation. The negatively charged nanoparticles were spherical in shape and approximately 30–50 nm in size, as observed by transmission electron microscopy (TEM). The amorphous characteristics of the nanoparticles were revealed by X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

The present work aims to prepare an ecofriendly and effective material for adsorption of heavy metals, especially iron and manganese from polluted water. Chitosan nanoparticles were prepared from the extracted chitosan of shrimp shells waste using a traditional ionic gelation method in presence of sodium tripolyphosphate as a cross-linker. To confirm the polymer structure and its characteristics, the prepared nanoparticles were characterized using FT-IR, X-Ray diffraction, TEM and SEM. Molecular weight, the degree of de-acetylation, ash content, particle size and zeta potential values were 3923 D, 75 %, 4 %, 331 nm and +38 mv, respectively. A batch equilibrium experiments were carried out to evaluate the chitosan nanoparticles as adsorbents of Fe (II) and Mn (II) ions from aqueous solutions. The removal efficiency and adsorption capacity were studied at different contact times, pH of the sorption medium, and initial metal ion concentration in the feed solution. The removal efficiency and maximum adsorption capacity of Fe (II) and Mn (II) were 99.8, 116.2 mg/g and 95.3%, 74.1mg/g, respectively. From the adsorption isotherm and kinetic studies, it was found that the Langmuir and the pseud-second order models, respectively, were more fitted in this study. [ABSTRACT FROM AUTHOR]

Microencapsulation is used for protection and release of bioactive compounds. Combination of encapsulation methods allows the production of matrices with better technological properties compared to the application of one of the methods alone. Use of ionic gelation produces porous microparticles, and coating it with a protein, by electrostatic interaction, may contribute to a better protection of the active compound. The objective of the research was to produce alginate microparticles (AG) through ionic gelation and to coat them with soluble protein from soy protein concentrate. Two factors were studied, calcium concentration during ionic gelation (0.8, 1.6 and 2.4% w/w) and pH (3.5 and 7.0) of the protein solution for electrostatic interaction. Zeta potential (ZP) of biopolymers and microparticles were determined. Microparticles were characterized according to its morphology, average size and size distribution, as well as protein adsorption. Microparticles presented (154-334μm) multinuclear distribution of active compound, continuous and smooth surface, with a great standard deviation considering average size. The calcium concentration did not influence the protein adsorption on microparticles.The pH used in protein adsorption showed significant effect, with higher adsorption occurring at pH 3.5 (6.5 to 6.7% w/w, dry basis,db, of adsorbed protein) compared to pH 7.0 (<2.0% w/w, db, of adsorbed protein) indicating that electrostatic interaction was determinant for the protein coating. At this situation, ionic gelation microparticles and proteins presented ZP with opposite charges (pH>pKa AG

Graphical abstract Highlights • Iron-pectin beads were obtained by ionic gelation. • Beads were analyzed using physical-chemical and physiological assays. • Beads were spherical, with high density and highly permeable. • The beads transported iron better than the FeSO 4 controls at intestinal level. • The beads are interesting systems to improve the efficiency of iron transport. Abstract Iron deficiency is the most common nutritional deficit worldwide. The goal of this work was to obtain iron-pectin beads by ionic gelation and evaluate their physiological behavior to support their potential application in the food industry. The beads were firstly analyzed by scanning electronic microscopy, and then physical-chemically characterized by performing swelling, thermogravimetric, porosimetry, Mössbauer spectroscopy and X-ray fluorescence analyses, as well as by determining the particle size. Then, physiological assays were carried out by exposing the beads to simulated gastric and intestinal environments, and determining the iron absorption and transepithelial transport into Caco-2/TC7 cells. Iron-pectin beads were spherical (diameter 1–2 mm), with high density (1.29 g/mL) and porosity (93.28%) at low pressure, indicating their high permeability even when exposed to low pressure. Swelling in simulated intestinal medium (pH 8) was higher than in simulated gastric medium. The source of iron [FeSO 4 (control) or iron-pectin beads] did not have any significant effect on the mineral absorption. Regarding transport, the iron added to the apical pole of Caco-2/TC7 monolayers was recovered in the basal compartment, and this was proportional with the exposure time. After 4 h of incubation, the transport of iron arising from the beads was significantly higher than that of the iron from the control (FeSO 4 ). For this reason, iron-pectin beads appear as an interesting system to overcome the low efficiency of iron transport, being a potential strategy to enrich food products with iron, without altering the sensory properties. [ABSTRACT FROM AUTHOR]

Hyaluronic acid (HA, 20-50 kDa) is a hydrophilic macromolecule with anti-wrinkle effects and moisturizing properties. However, its high molecular weight prevents it from penetrating into the deeper layers of the skin and, thus, limits its benefits to topical effects. Thus, the objective of this study is to prepare nanoparticles of quaternized cyclodextrin-grafted chitosan (QCD-g-CS) associated with HA in different molar ratios of QCD-g-CS and HA. The conjugation of the carboxylic moieties of HA and the amides of QCD-g-CS was confirmed by Fourier-transform infrared spectroscopy. Thus, the system was optimized to create nanoparticles with a small size (235.63 ±21.89 nm), narrow polydispersity index (0.13 ±0.02), and zeta potential of 16.07 ±0.65 mV. The association efficiency and loading efficiency were determined by ultra-performance liquid chromatography as 86.77 ±0.69% and 10.85 ±0.09%, respectively. The spherical morphology of the obtained nanoparticles was confirmed by transmission electron microscopy. Moreover, the in - vitro hydrating ability was significantly higher ( P < 0.001) than that of bulk HA (3.29 ±0.41 and 1.71 ±0.05 g water/g sample, respectively). The safety of these nanoparticles at concentrations in the range of 0.01-0.10 mg/ml was confirmed via tests on human skin fibroblasts. Together, these results demonstrate that the developed nanoparticles are promising for future applications in cosmetics. [ABSTRACT FROM AUTHOR]

Doxorubicin is one of the most effective chemotherapeutic agents for the treatment of several neoplastic conditions, such as leukemia, neuroblastoma, soft tissue and bone sarcomas, breast cancer, ovarian cancer and others. However, its clinical application is limited by cardiotoxicity, such as cardiomyopathy, that once developed carries a poor prognosis and is frequently fatal. The controlled release of doxorubicin by means of a smart carrier is a strategy to overcome the aforementioned drawback. Herein, doxorubicin/keratin nanoparticles were prepared by loading the drug through ionic gelation and aggregation methods, without using cross linkers, organic solvents neither surfactants. Both methodologies afford nanoparticles with yields up to 100 wt%, depending on the loading amount of doxorubicin. Although aggregation yield smaller nanoparticles (≈100 nm), ionic gelation allows a higher drug loading (up to 30 wt%,). More importantly, nanoparticles obtained through this procedure display a pH-responsive release of the drug: indeed Peppas-Salhin model suggests that, the doxorubicin release mechanism is predominantly controlled by diffusion at pH 7.4 and by protein swelling at pH 5. Moreover, nanoparticles prepared by ionic gelation resulted in more efficient cell killing of MDA-MB-231 and MCF-7 breast cancer cells than those prepared by aggregation. Based on the herein presented preliminary results, ionic gelation emerges as a promising approach for the preparation of keratin-based doxorubicin nanocarriers for cancer therapy, that is worth to further investigate. [ABSTRACT FROM AUTHOR]

Alginate hydrogels are often used for immobilization of plant-derived bioactive compounds by fast and simple ionic gelation technique. However, the structure of alginate gel network is very porous and mostly result with high-diffusion rates of encapsulated compound, what limits its application as delivery vehicle. In order to prevent losses of bioactives and prepare efficient encapsulation systems, the aim of this study was to evaluate a potential of new natural fillers, cocoa powder (CP) and carob (C) for structuring alginate network aimed for encapsulation of aqueous dandelion ( Taraxacum officinale L.) leaf extract using ionic gelation. Whey protein isolates served as a standard filler. The influence of different concentrations of gelling medium (2% and 3% calcium chloride) on encapsulation properties of alginate systems was also evaluated. Calcium concentration affected morphological properties (more acceptable when using 3% CaCl 2 ), while textural properties and encapsulation efficiency of polyphenols and retained antioxidant capacity were more influenced by selected delivery materials. Alginate-whey protein isolates beads were scored with the highest loading capacity of polyphenols (>93%), while newly formulated binary mixtures (alginate-cocoa powder and alginate-carob) also enabled highly efficient entrapment of polyphenols (>88%). The slowest release of polyphenols in simulated gastrointestinal fluids were obtained when alginate was combined with CP and C, where system alginate-cocoa powder prepared with lower concentration of calcium chloride (2% CaCl 2 ) enabled the most extended release of total polyphenols and hydroxycinnamic acids. Obtained results strongly justified implementation of new plant-derived functional fillers (cocoa powder and carob) for encapsulation purposes and opened new directions for designing of binary carrier's. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this study was to investigate the effect of andrographolide-carboxymethyl chitosan nanoparticles formation on the physical characteristics, in vitro release profile and in vivo antimalarial activity of andrographolide. Materials and Methods: Nanoparticles were prepared by ionic gelation method-spray drying using CaCl2 as the crosslinker with a composition of drug: polymer: CaCl2=40: 250: 100. The obtained particles were evaluated for its size and morphology; physical state, drug content, in vitro drug release and in vivo antimalarial activity on Plasmodium berghei infected mice. Results: The results of DTA and XRD showed that nanoparticle systems had a lower melting point and lower crystallinity degree. The drug dissolved from the nanoparticles was increased up to 6.5 times and the in vivo antimalarial activity was 1.65 times higher compared to andrographolide. Conclusion: The formation andrographolide-carboxymethyl chitosan nanoparticles affected the physical characteristics of andrographolide. The decrease crystallinity of andrographolide resulted in a lower melting point of andrographolide. Such changes provided a positive impact to the drug dissolution and then its activity. [ABSTRACT FROM AUTHOR]

The objective of this study is to demonstrate an effective technique with potential for commercialization for microsphere production. Ultrasound-assisted ionic gelation of sodium alginate was used to encapsulate simvastatin. Chitosan was used as a mucoadhesive polymer for gastroretention of microsphere. Sodium alginate solution was sonicated using probe sonicator at a frequency of 20±3 KHz and ultrasonic power of 130 W with an input voltage range of 170-270 AC, 50 Hz, at a temperature of 50°. The influence of ultrasound waves on drug entrapment efficiency, yield and particle size dispersion was studied in comparison to mechanical stirring method. Mucoadhesiveness, release pattern and kinetics of drug release were also characterized. Ultrasound treatment caused small fissures and depressions on the surface of alginate as evidenced in SEM. Ultrasound of 20±3 KHz for 12 min duration was the optimum frequency and time in the experimental set up to obtain microspheres with uniform and smaller microparticles. The encapsulation efficiency of simvastatin was directly proportional to the sonication effect, concentration of alginate and extent of its cross linkage with calcium ions. DSC studies revealed that ultrasound treatment did not alter the structural integrity of the drug component. Formulation was found to be dissolution efficient and drug release pattern was concentration-dependent, which followed non-Fickian diffusion mechanism with an 'n' value of 0.8. Therefore, it could be concluded that ultrasound can be used as an efficient technology to develop drug-entrapped microsphere for controlled delivery. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate the effect of Prosopis alba exudate gum (G) as encapsulating matrix component on water-solid interactions, physical state, oxidative damage and appearance properties of alginate-chitosan encapsulates containing fish oil. With this purpose, water sorption isotherms were obtained at 25 °C. G increased the hygroscopicity of encapsulates, showing a higher monolayer water content (7.87 ± 0.47% db.) than control (1.07 ± 0.04% db.). G introduction reduced the plasticizing effect of water, increasing the a w range (a w  < 0.45) at which samples were in amorphous state and providing the highest protection against lipid oxidation. Appearance properties (chromatic and optical) were affected by hydration and were better maintained in samples containing G at a w  > 0.52. These results allow considering Prosopis alba exudate gum, as a novel excipient to protect fish oil encapsulated in low moisture polyelectrolyte systems, with the added benefits of employing an undervalued natural resource. [ABSTRACT FROM AUTHOR]

The purpose of this study was to synthesise, characterize and evaluate environmental application (degradation of dyes and pesticides) of chitosan nanoparticles. The chitosan nanoparticles were synthesized by ionic gelation process and characterized. The physicochemical properties of the nanoparticles were determined by size and zeta potential analysis, scanning electron microscope (SEM), atomic force microscopy (AFM), FTIR analysis and XRD pattern. The photocatalytic degradation was studied with the help of industrial dyes, and pesticides. Adsorption experiments were carried out to highlight the adsorption efficiency of the organic compound with different parameters like pH, dosage and time. A sharp increase in the percent reduction of dyes and pesticides was observed as the adsorbent dose increased. The kinetic data were modelled with the pseudo first-order and pseudo second-order kinetic equations. [ABSTRACT FROM AUTHOR]

Purpose: Conventional topical delivery in hyperacute bacterial conjunctivitis and endophthalmitis is associated with low drug bioavailability due to rapid precorneal clearance. Hence, in the present investigation, an attempt has been made to enhance ocular bioavailability of tobramycin sulfate by formulating drug-loaded microparticles dispersed in thermosensitive in situ gel.Methods: Microparticles prepared by emulsion-ionic gelation technique were characterized for drug loading, entrapment efficiency, particle size, surface morphology, and in vitro drug release. Consequently microparticles (F2 prepared with 1.5%w/v chitosan, 0.2%w/v tripolyphosphate, and drug, 30%w/w of polymer) with high drug loading and encapsulation efficiency were dispersed in thermosensitive in situ gel containing poloxamer 407 and varying percentage of chitosan. In situ gel containing drug-loaded microparticles were evaluated for gelation temperature, rheological behavior, mucoadhesive strength, in vitro drug release, in vitro permeation, ocular irritation, and bioavailability in aqueous humor of rabbits.Results: Formulation containing 17%w/v poloxamer 407 and 0.5%w/v chitosan (P2) gelled at 32°C ± 1.5°C gave pseudoplastic behavior. In vitro permeability of tobramycin from the formulation P2 was found 2-folds greater than eye drops. It also gave significantly higher aqueous humor concentration of tobramycin compared with eye drops with no signs of ocular irritation.Conclusion: Thus, the formulation possesses high potential for treating ocular infections. [ABSTRACT FROM AUTHOR]

The current study is aimed at developing Plantago ovata F. husk mucilage (PHM)-blended Zn2+-crosslinked low methoxyl (LM) pectinate (PHM-Zn2+- LM-pectinate) controlled-release matrices containing aceclofenac (ACF) for the management of rheumatoid arthritis (RA) in patients with an outright zinc deficiency. The ACF-encapsulated hydrogel matrices are accomplished by ionic gelation using ZnSO4 as a crosslinker. The matrix diameter ranges from 1.39±0.14 to 1.62±0.16 mm. These formulations demonstrate excellent drug encapsulation efficiency (DEE, 63.80±1.73-90.56±2.72%) and controlled drug-release behavior over a prolonged period of time (Q10 h, 51.42±3.10 to 92.60±2.38%). The drug-elution patterns of different matrices are best-fitted by a zero-order kinetic model with a case-II-transportdriven mechanism. The matrices also depict pH-dependent swelling and degradation properties. In addition, the composites are characterized by scanning electron microscopy (SEM), Fourier transform IR (FTIR), and powder X-ray diffraction (P-XRD) analyses. Thus, the newly developed PHM-Zn+2-LM-pectinate matrices could be appropriate for controlled ACF delivery along with Zn supplementation in the effective treatment of RA. [ABSTRACT FROM AUTHOR]

In the present study, β-cyclodextrin-grafted chitosan nanoparticles (β-CDg- CS NPs) were prepared using a new ionic gelation strategy involving a synergistic effect of NaCl (150 mmol/L), 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES, 10 mmol/L), and water bath sonication. This new strategy afforded smaller and more monodisperse β-CD-g-CS NPs vs. the classical ionic gelation method. New HA/β-CD-g-CS NPs were also prepared using the above-mentioned strategy by adding hyaluronic acid (HA) to the β-CD-g-CS copolymer at different weight ratios until the ZP values conversion. The best result was obtained with the weight ratio of w(HA):w(β-CD-g-CS) = 2:1 and furnished new spherical and smooth HA/β-CD-g-CS NPs. Furthermore, the stability of β- CD-g-CS NPs and HA/β-CD-g-CS NPs at 4°C in physiological medium (pH 7.4) was compared for 3 weeks period and showed that HA/β-CD-g-CS NPs were more stable all maintaining their monodispersity and high negative ZP values compared to β-CD-g-CS NPs. Finally, preliminary study of HA/β-CD-g-CS NPs as carrier for the controlled release of the anticancer drug doxorubicin was investigated. These new HA/β-CD-g-CS NPs can potentially be used as drug delivery and targeting systems for cancer treatment. [ABSTRACT FROM AUTHOR]

Hibiscus extract (HE) has a strong antioxidant activity and high anthocyanin content; it can be used as a natural pigment, also adding potential health benefits. The objective of this work was the microencapsulation of HE anthocyanin by ionic gelation (IG) using two techniques: dripping-extrusion and atomization, both by means of a double emulsion (HE/rapseed oil/pectin) and a cross-linked solution (CaCl 2 ). Particles (77–83% moisture content) were conditioned in acidified solution at 5, 15 and 25 °C, absence of light, and evaluated for anthocyanins and color for 50-days. The median diameter (D 50 ) of the particles ranged from 78 to 1100 μm and encapsulation efficiency ranged from 67.9 to 93.9%. The encapsulation caused higher temperature stability compared with the free extract. The half-life (t 1/2 ) values of the particles ranged from 7 (25 °C) to 180 days (5 °C) for anthocyanins and from 25 (25 °C) to 462 days (5 °C) for Chroma value. The IG increased the stability of HE anthocyanin. Both the dripping-extrusion and the atomization have shown to be feasible techniques. [ABSTRACT FROM AUTHOR]

Objectives: Colon drug delivery system should be able to maintain drug release until the system reaches its target. In this study, beads were selected as drug carrier system to deliver tetrandrine to colon using a combination of two polymers, alginate and polyvinyl alcohol (PVA) and also alginate and carboxymethyl cellulose (CMC). It was hypothesized that alginate/PVA beads and alginate-CMC beads may be able to protect the drug effectively while in the gastrointestinal tract and may deliver the drug at colon under the influence of colonic pH. Materials and Methods: Beads were formulated into six formulae with different concentrations of polymer. Beads were characterized and evaluated for in vitro drug release using dissolution method. Results: Beads' Formula 3 (alginate and PVA 2:1) and Formula 6 (alginate and CMC 2:1.5) were the best formulae with entrapment efficiency 32.12% and 39.83%, respectively. The drug release test was performed first in hydrochloric acid (HCl) medium for 2 h, then in phosphate-buffered pH 7.4 + 2% Tween 80 for 3 h, and finally in phosphate-buffered pH 6.8 + 2% Tween 80 medium for 3 h, successively. The results of drug release in HCl pH 1.2 were 84.13%, 73.12%, 66.57%, 85.59%, 78.26%, and 69.56%, for Formula 1, 2, 3, 4, 5, and 6, respectively. Conclusion: All type of beads showed the high release of tetrandrine in HCl; hence, it is not ideal yet as a colon-targeted dosage form. [ABSTRACT FROM AUTHOR]

Chitosan is the second most abundant polymer obtained from the byproduct of seafood. Chitosan and its derivatives and chitosan loaded drugs are the recent area of interest against microbial pathogenesis. The cationic chitosan nanoparticles (ChNPs) interact with the anionic surfaces of the microbial cell membrane, which promotes antimicrobial activity. Although, ChNPs are potential against pathogenic microbes, selection of adaptable, suitable and cost effective synthesis method is much important. In the present study, ChNPs were synthesized adopting ionic gelation using sodium tripolyphosphate as a cross linking agent and characterized by FTIR, DLS, SEM and TEM analysis. ChNPs were investigated for antimicrobial activity against bacterial ( Escherichia coli and Staphylococcus aureus ) and fungal ( Candida albicans ) pathogens. ChNPs showed bactericidal activity at the lower minimum inhibitory concentration of about 40–80 μg mL −1 . Interestingly, ChNPs exhibits biocompatible antioxidant property by inhibiting DPPH free radicals at 76% and also proven to be a potential candidate against the microbial pathogenesis with an inevitable applications in biomedicine. [ABSTRACT FROM AUTHOR]