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Purpose: Epalrestat is the most common Aldose reductase inhibitor (ARI) approved for blood glucose management in several countries and has also shown efficacy in preventing the onset of diabetic neuropathy (DN), and diabetic retinopathy. The present study aims to formulate and evaluate the effectiveness of Alginate beads of epalrestat in Streptozotocin-induced (STZ) diabetic rats in order to effectively manage the diabetes. Method: Various formulations of Sodium cross-linked alginate beads containing epalrestat (F1 to F9) were prepared based on full factorial design by ionotropic gelation method. The formulations were characterized for particle size, % Drug entrapment efficiency (DEE), Fourier Transform Infra-Red Spectroscopy (FT-IR), Differential scanning calorimetry (DSC), X-ray Diffraction Study (X-RD), Scanning Electron Microscopy (SEM), and In-Vitro Release Studies. Optimized formulation (F6) [containing sodium alginate (2.5%w/v), epalrestat (2.5%w/v), and calcium chloride (2.5%w/v)] was subjected to in-Vivo efficacy testing in diabetic rats. Result: Epalrestat-loaded beads were prepared (F1 to F9; Size = 3.21 μm; DEE = 97%) successfully using sodium alginate as polymer and calcium chloride solution as the crosslinking agent by modified ionotropic gelation method Optimized formulation showed a % DEE of 97% and highest drug release of 95% at the end of 10 hrs. Drug Release Kinetic of optimized formulation followed first-order kinetic. Further, the hypoglycemic effect was observed over a longer period 50% reduction after 2 hrs and continued till 4 hrs. In addition, normoglycemia was maintained till 12 hrs (20% reduction) in STZ-induced diabetic rats. Conclusion: The formulation F6 was found to be superior compared to all the other formulations because the percentage drug entrapment efficiency was highest and there was no chemical interaction took place between the drug and polymer (Confirmed by DSC and XRD studies). In-vivo study showed prolonged hypoglycaemia till 12 hrs with a maximum reduction at 2 hrs Compared to plain drug suspension (20% reduction till 5 hrs). [ABSTRACT FROM AUTHOR]

The peel of Citrus limon is a colossal organic byproduct of the juice industry containing a significant quantity of bioactive polyphenols with diverse therapeutic potentials. As they are often underutilized the present investigation aims to valorize and promote the utilization of these polyphenols through encapsulation in a hydrocolloid-based hydrogel matrix for prolonged shelf-life and sustainable delivery. The hydrogels were prepared by blending sodium alginate and pectin through ionotropic gelation which achieved ∼86.72 % polyphenol encapsulation efficiency. The polyphenol-encapsulated hydrogels had maintained the shelf life and effectively preserved >95 % of polyphenols at 30 °C with no discernible variation for >30 days. Multiple physicochemical investigations were performed on the prepared formulation. Additionally, the release kinetics of polyphenols from beads were examined in a simulated gastrointestinal environment. The result showed that ∼87.54 % of entrapped polyphenol was released after 9 h and the pattern was found controlled release type and pH-responsive. The degree of fluctuation of a few specific polyphenolic compounds was noted and evaluated using principal component analysis. Furthermore, the encapsulating procedure protected a considerable amount of antioxidant activity (>60 %) while demonstrating good hemocompatibility. Therefore, the produced formulation may be used by the juice industries to create a valorization step using the byproduct. [Display omitted] • Citrus limon peel polyphenols were encapsulated in hybrid network hydrogel. • Suitable sustained release profile observed along with bioavailability. • Variation of selected polyphenols was assessed using principal component analysis. • In silico study revealed the biocompatibility of the polyphenols. • New valorization step added to the processing of juice industry byproduct. [ABSTRACT FROM AUTHOR]

Encapsulation is a popular approach used to incorporate lipophilic bioactive molecules in food matrices. In the present work, soybean oil emulsions with different oil volume fractions (ϕ = 0.17 and ϕ = 0.26) stabilized by whey protein aggregates (WPAg), were mixed with sodium alginate (SA) suspensions and atomized over a calcium gelling bath using an airbrush atomization system to obtain emulsion microgel particles (EMP). Rheological measurements of the mixtures of microgel‐stabilized emulsions and SA suspensions showed a significant increase in viscosity when the oil volume fraction was increased. The analysis of the flow curves showed that viscosity decreased with the increase of shear rate for both systems indicating shear thinning behavior. No difference in the size distribution curves of EMP obtained with different oil fractions was observed. The average D4,3 and span values were 509 ± 56 μm, 1.14 ± 0.08 (ϕ = 0.17), and 527 ± 51 μm, 1.19 ± 0.06 (ϕ = 0.26). The encapsulation efficiency in both cases was acceptable (89 ± 5% for ϕ = 0.17 and 74 ± 8% for ϕ = 0.26), and none of the microparticles showed oil release after 2 months of storage. Results showed that the airbrush atomization system to obtain alginate‐based EMP is simple, low‐cost, and does not require heating, making it appropriate for the effective encapsulation of labile lipophilic compounds in the food industry. [ABSTRACT FROM AUTHOR]

Phenolic compounds that are present in pineapple by-products offer many health benefits to the consumer; however, they are unstable to many environmental factors. For this reason, encapsulation is ideal for preserving their beneficial effects. In this work, extracts were obtained by the combined method of solid-state fermentation with Rhizopus oryzae and ultrasound. After this process, the encapsulation process was performed by ionotropic gelation using corn starch, sodium alginate, and Weissella confusa exopolysaccharide as wall material. The encapsulates produced presented a moisture content between 7.10 and 10.45% (w.b), a solubility of 53.06 ± 0.54%, and a wettability of 31.46 ± 2.02 s. The total phenolic content (TPC), antioxidant capacity of DPPH, and ABTS of the encapsulates were also determined, finding 232.55 ± 2.07 mg GAE/g d.m for TPC, 45.64 ± 0.9 µm Trolox/mg GAE for DPPH, and 51.69 ± 1.08 µm Trolox/mg GAE for ABTS. Additionally, ultrahigh performance liquid chromatography (UHPLC) analysis allowed us to identify and quantify six bioactive compounds: rosmarinic acid, caffeic acid, p-coumaric acid, ferulic acid, gallic acid, and quercetin. According to the above, using ionotropic gelation, it was possible to obtain microencapsulates containing bioactive compounds from pineapple peel extracts, which may have applications in the development of functional foods. [ABSTRACT FROM AUTHOR]

The ionotropic gelation technique was chosen to produce vitamin D3-loaded microparticles starting from oil-in-water (O/W) Pickering emulsion stabilized by flaxseed flour: the hydrophobic phase was a solution of vitamin D3 in a blend of vegetable oils (ω6:ω3, 4:1) composed of extra virgin olive oil (90%) and hemp oil (10%); the hydrophilic phase was a sodium alginate aqueous solution. The most adequate emulsion was selected carrying out a preliminary study on five placebo formulations which differed in the qualitative and quantitative polymeric composition (concentration and type of alginate selected). Vitamin D3-loaded microparticles in the dried state had a particle size of about 1 mm, 6% of residual water content and excellent flowability thanks to their rounded shape and smooth surface. The polymeric structure of microparticles demonstrated to preserve the vegetable oil blend from oxidation and the integrity of vitamin D3, confirming this product as an innovative ingredient for pharmaceutical and food/nutraceutical purposes. [ABSTRACT FROM AUTHOR]

Purpose: Microencapsulation is a technique employed in the development of controlled drug delivery systems. It is beneficial in reducing dosing frequency, ensuring targeted drug delivery, and improving drug bioavailability. The objective of this study was to evaluate the effectiveness of Cyperus esculentus starch and its derivative in the development of microbeads for sustained delivery of ibuprofen. Methods: Ibuprofen-loaded microbeads were prepared by ionotropic gelation using Cyperus esculentus starch and its derivative in combination with sodium alginate at concentrations of 1:1, 1:2, and 2:1 and calcium chloride solution as cross-linker. Morphology of the microbeads by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), and differential scanning calorimetry (DSC) were investigated. Entrapment efficiency, swelling capacity, mucoadhesion, and in vitro drug release were also evaluated. Results: SEM showed that the microbeads were spherical to irregular in shape, FT-IR returned prominent peaks specific for ibuprofen and absence of new peaks, DSC revealed evidence of entrapment of ibuprofen in the microbeads, and entrapment efficiency ranged between 46.05 and 89.86%. Microbeads prepared with native and cross-linked starches showed better mucoadhesion, and those prepared with cross-linked starch blend exhibited highest swelling capacity. In vitro release was pH dependent, and increasing the concentration of cross-linked starch in the blend caused greater retardation of drug release (45.19%) than the formulations containing native starch-alginate blend or sodium alginate alone. Conclusion: The blend of cross-linked Cyperus esculentus starch and sodium alginate shows propensity to sustain ibuprofen release and could be exploited for targeted delivery especially to the lower GIT. [ABSTRACT FROM AUTHOR]

Combinations of polymers can improve the functional properties of microspheres to achieve desired therapeutic goals. Hence, the present study aimed to formulate Prunus armeniaca gum (PAG) and sodium alginate microsphere for sustained drug release. Blended and coated microspheres were prepared using the ionotropic gelation technique. The effect of polymer concentration variation was studied on the structural and functional properties of formulated microspheres. FTIR, XRD, and thermal analysis were performed to characterize the microspheres. All the formulations were well-formed spherical beads having an average diameter from 579.23 ± 07.09 to 657.67 ± 08.74 μm. Microspheres entrapped drugs within the range 65.86 ± 0.26–83.74 ± 0.79%. The pH-dependent swelling index of coated formulations was higher than blended. FTIR spectra confirmed the presence of characteristic peaks of entrapped Tramadol hydrochloride showing no drug-polymer interaction. In vitro drug release profile showed sustained release following the Korsmeyer-Peppas kinetic model with an R2 value of 0.9803–0.9966. An acute toxicology study employing the oral route in Swiss albino mice showed no signs of toxicity. It can be inferred from these results that blending PAG with sodium alginate can enhance the stability of alginate microspheres and improve its drug release profile by prolonging the release time. [ABSTRACT FROM AUTHOR]

The ionotropic gelation technique was chosen to produce vitamin D3-loaded microparticles starting from oil-in-water (O/W) Pickering emulsion stabilized by flaxseed flour: the hydrophobic phase was a solution of vitamin D3 in a blend of vegetable oils (ω6:ω3, 4:1) composed of extra virgin olive oil (90%) and hemp oil (10%); the hydrophilic phase was a sodium alginate aqueous solution. The most adequate emulsion was selected carrying out a preliminary study on five placebo formulations which differed in the qualitative and quantitative polymeric composition (concentration and type of alginate selected). Vitamin D3-loaded microparticles in the dried state had a particle size of about 1 mm, 6% of residual water content and excellent flowability thanks to their rounded shape and smooth surface. The polymeric structure of microparticles demonstrated to preserve the vegetable oil blend from oxidation and the integrity of vitamin D3, confirming this product as an innovative ingredient for pharmaceutical and food/nutraceutical purposes.

Ionotropic gelation followed by polyelectrolyte complexion was used for the synthesis of nanoparticles based on sodium alginate (NaAL) and chitosan (CS) for encapsulation of ibuprofen (IBP), Fourier transform infrared spectroscopy, differential scanning calorimetry, field-emission scanning electron microscopes, percentage of encapsulation efficiency and loading capacity have been used to confirm the synthesis and encapsulation of IBP. The results obtained show that they have a size of around 100 nm. In vitro drug release and evaluation of anti-inflammatory activity in different media indicate that the nanoparticles are pH-sensitive and permit the protection of the drug against total dissolution in the gastric medium, control its release, and it increases the solubility and biological activity of IBP. The analytical data of the in vitro drug release in the simulated gastric fluid (SGF), simulated interstitial fluid (SIF) and phosphate buffered saline (PBS) were fitted to the different kinetic models (zero-order, first-order, Higuchi, Korsmeyer–Pepass and Kopcha), and the results indicate that IBP is released by diffusion-controlled in SIF and PBS, and by erosion-controlled in the SGF. The toxicity of nanoparticles was tested against Artemia salina that displayed non-toxicity effects. In vitro biodegradation by lysozyme and all the results obtained indicated that a NaAL/CS nanoparticles are a promising system for IBP release that can achieve pseudo-zero-order kinetics. [ABSTRACT FROM AUTHOR]

Curcumin, a bioactive compound derived from the rhizome of Curcuma longa , has gained widespread attention for its potential therapeutic properties, including anti-inflammatory, antioxidant and anticancer effects. However, its poor aqueous solubility, instability and limited bioavailability have hindered its clinical applications. New beads formulations based on sodium alginate biopolymer (SA) and poly vinyl alcohol (PVA) were successfully prepared and evaluated as a potential drug vehicle for extended release of curcumin (Cur). Pristine and curcumin loaded calcium alginate/poly vinyl alcohol beads (CA/PVA and CA/PVA/Cur) at different compositions of SA and PVA were prepared by an ionotropic gelation method of SA followed by two freeze-thawing (FT) cycles for further crosslinking of PVA. Characterization techniques, such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), UV–Visible spectroscopy, thermogravimetric analysis (TGA) and x-ray diffraction (XRD) were used to confirm the successful microencapsulation of curcumin within the CA/PVA microcapsules. Furthermore, the swelling of pristine beads, pH-sensitive properties and in vitro release studies of curcumin loaded beads were investigated at 37 °C in simulated gastric fluid (SGF), simulated intestinal fluid (SIF) and simulated colonic fluid (SCF). The effect of the polymer blend ratio, the encapsulation efficiency (EE %) of curcumin, the loading capacity (LC μg/mg), the sphericity factor (SF), the antioxidant activity of the elaborated beads and their antimicrobial properties against bacteria and fungi were just as much evaluated. The obtained results indicate that the swelling and the behavior of the developed beads were influenced by the pH of the test medium and the PVA content. The introduction of PVA into the SA matrix greatly enhanced the physicochemical properties, the encapsulation efficiency and the loading capacity of the elaborated microparticles. Results also suggested that the antioxidant activity of the loaded beads (CA/PVA/Cur) showed a higher DPPH radical scavenging activity while the bacterial and fungal strains proved sensitive to the different formulations used in the assay. Moreover, the important drug encapsulation efficiency and the sustainable drug release of these materials make them promising for the development of new drug carrier systems for colon targeting. [Display omitted] [ABSTRACT FROM AUTHOR]

A natural polysacharide, gum odina was collected from Odina wodier tree and purified. Purified gum odina was used with sodium alginate for immobilization of α-amylase. Calcium alginate-gum odina (CA-GO) beads were prepared by ionotropic gelation method to find the improvement of immobilization efficiency and reusability of α-amylase over calcium alginate (CA) beads. XRD, SEM, FTIR, beads diameter, enzyme leaching from beads, moisture content, total soluble matter and swelling study have been carried out to understand the physical morphology and mechanism of immobilization of enzyme in beads matrix. It has been observed that if the polymer ratio changes (keeping enzyme conc. & calcium Chloride conc. constant) then the size and shape of the beads will vary and at a particular range of polymer ratio, the optimal beads forms. At a certain conc.(4% w / v of SA and 1%w/v GO), the immobilization efficiency of CA-GO and CA beads were 92.71 ± 0.85 % (w /w) and 89.19 ± 0.35 %(w/w) respectively. After 8th time use, the CA-GO beads remain (~4 fold) more active than that of CA beads. The FTIR confirms that GO does not interfere with α-Amylase and alginate. Here, it can be concluded that CA-GO beads show better efficiency in respect to immobilization, reusability than CA beads only. [ABSTRACT FROM AUTHOR]

[Display omitted] • The pH of ionotropic gelation affected the properties of the microparticles. • One-step approach is promising for bioactive release into low pH values. • Two-step approach is promising for bioactive release into high pH values. • Alginate-chitosan gels produced at pH 2.5 showed higher encapsulation efficiency. Alginate is a biopolymer widely used on delivery systems when bioactive protection at acidic pH is required, while chitosan can enhance mucoadhesion and controlled release at alkaline pHs. In this work, alginate ionotropic gelation and electrostatic complexation to chitosan were evaluated concomitantly or in a two-step approach to improve the delivery properties of systems in different pHs. The effect of pH on alginate gelation and chitosan interactions were also evaluated. Alginate microspheres were prepared by ionotropic gelation in CaCl 2 at different pH values (2.5 and 6.0) by extrusion. Complexation with chitosan was carried out during alginate ionotropic gelation (one-step approach) or after alginate gel formation (two-step approach). Alginate microparticles without chitosan showed larger pores and lower mechanical strength. Extruded microspheres at pH 6.0 were more stable to pH and showed smaller pores than the formed at pH 2.5. One-step production retained a large amount of bioactive at pH 7.0 and resulted in lower release at the pH of intestinal digestion. The two-step approach retained less amount of bioactive but confer more protection to the pH of the stomach phase and higher release in pH of the intestinal phase than one-step samples. These results indicate that the formation of alginate gels by ionotropic gelation followed by the complexation with chitosan (in two-step) is promising for the transport and delivery of bioactives into intestinal conditions, whereas the ionotropic gelation concomitantly to electrostatic complexation (one-step approach) is indicated to the delivery of bioactives into lower pH environments. [ABSTRACT FROM AUTHOR]

In the present contribution we focus on the fabrication and characterization of targeted delivery systems suitable for encapsulation of hesperidin (HESP) − a natural health-promoting flavonoid glycoside. We fabricated and extensively studied pH-responsive, biodegradable double-compartment hydrogel carriers composed of sodium carboxymethyl cellulose particles (ACP) filled with hesperidin-loaded sodium alginate microparticles (AMP). Additionally, hesperidin was encapsulated directly in sodium alginate or sodium carboxymethyl cellulose particles (AP or CP, respectively). The obtained carriers were characterized in respect to their morphology and size by using scanning electron microscopy (SEM). The cargo encapsulation was confirmed by spectroscopic analysis (FTIR), while the process efficacies were derived spectrophotometrically (UV–vis). The effect of different pH on the stability of the beads has been assessed. The in vitro release kinetics of the fabricated HESP-loaded particles was studied in simulated gastric and intestinal environments. The fabrication processes yielded stable particles of desired properties. Comparing the results obtained for both single- and double-compartment systems, makes it possible to conclude that the latter is superior in regard to prolonged delivery of hesperidin to the place of action under simulated intestinal conditions. [ABSTRACT FROM AUTHOR]

In this work, a bottom-up approach based on the study of polyelectrolyte interactions was performed in order to evaluate the effect of Prosopis alba exudate gum as novel excipient for fish oil encapsulation in composed calcium-alginate-chitosan beads. Emulsion and beads properties such as oil distribution, encapsulation efficiency, yield, microstructure and thermo-oxidative protection were evaluated. Alginate and gum exert a synergistic effect on emulsion stability properties, which conducted to better oil distribution in the beads and higher encapsulation efficiencies (98%) and yield (89%). The positive effect of including the gum as wall material was observed in terms of a higher oil retention capacity of the alginate beads, improved oxidative thermal stability and better microstructural features. Present results are promising and allowed considering P. alba gum as a novel non-conventional polyelectrolyte for improving Ca-alginate beads microstructure and stability with the added benefit of taking advantage of an available resource currently untapped. [ABSTRACT FROM AUTHOR]

The objective of this study was to develop a sustained release dosage form of Trimetazidine dihydrochloride (TMZ) using a natural polymeric carrier prepared in a completely aqueous environment. TMZ was entrapped in calcium alginate beads prepared with sodium alginate by the ionotropic gelation method using calcium chloride as a crosslinking agent. The drug was incorporated either into preformed calcium alginate gel beads (sequential method) or incorporated simultaneously during the gelation stage (simultaneous method). The beads were evaluated for particle size and surface morphology using optical microscopy and SEM, respectively. Beads produced by the sequential method had higher drug entrapment. Drug entrapment in the sequential method was higher with increased CaCl2 and polymer concentration but lower with increased drug concentration. In the simultaneous method, drug entrapment was higher when polymer and drug concentration were increased and also rose to a certain extent with increase in CaCl2 concentration, where further increase resulted in lower drug loading. FTIR studies revealed that there is no interaction between drug and CaCl2. XRD studies showed that the crystalline drug changed to an amorphous state after formulation. Release characteristics of the TMZ loaded calcium alginate beads were studied in enzyme-free simulated gastric and intestinal fluid.O objetivo deste estudo foi desenvolver forma de liberação controlada de dicloridrato de trimetazidina (TMZ) utilizando transportador plomérico natural em ambiente completamente aquoso. A TMZ foi presa em pérolas de alginato de cálcio preparadas com alginato de sódio pelo método de gelatinização ionotrópica, usando cloreto de cálcio como agente de formação de ligações cruzadas. O fármaco foi incorporado nas pérolas de gel de alginato de cálcio (método sequencial) ou incorporado, simultaneamente, durante o estágio de gelificação (método simultâneo). As pérolas foram avaliadas quanto ao tamanho das partículas e morfologia da superfície utilizando microscopia óptica de SEM, respectivamente. As pérolas produzidas pelo método sequencial apresentaram maior capacidade de inclusão. No método sequencial, a inclusão de fármaco foi maior com o aumento de CaCl2 e da concentração do plímero, mas menor com o aumento da concentração de fármaco. No método simultâneo, a inclusão de fármaco foi mais alta quando as concentrações de fármaco e plímero foram aumentadas e, também, atingiram certa extensão com aumento na concentração de CaCl2, cujo aumento posterior resultou em carga menor de fármaco. Estudos de FTIR revelaram que não há interação entre fármaco e CaCl2. Estudos de XRD mostraram que o fármaco mudou do estado cristalino para o amorfo após a formulação. As características de liberação de TMZ das pérolas carregadas com alginato de cálcio foram estudadas em fluidos simulados, gástrico e intestinal, livres de enzima.

Alginate is a natural polysaccharide that is widely used in industrial applications. Here, beads of alginic acid, calcium, and copper alginate were prepared by the addition of soluble sodium alginate to a solution of hydrochloric acid or the corresponding cation. The progress of gelation inside the beads was followed by the degree of opacity at different times, which corresponded well to an apparent morphology change observed in freeze-dried bead cross sections analyzed by scanning electron microscopy. Furthermore, diffusion of Cu2+ions across the beads was followed by energy dispersive X-ray spectroscopy, which revealed colocalization of the cross-linking cation and the morphologically distinct bead regions. [ABSTRACT FROM AUTHOR]

In the present work, sodium alginate (SA), low methoxyl pectin (PEC) and κ-carrageenan (κ-CAR) were evaluated for their intragastric structuring ability by means of light microscopy and dynamic oscillatory rheology. SA and PEC solutions, their Ca 2+ complexed gel analogues as well as their binary blends with ionically or thermally set sheared κ-CAR gels, were subjected to in vitro orogastric conditions. SA and PEC – Ca 2+ complexed sheared gels exerted the highest vulnerability to digestive fluid exposure due to the dialysis of egg-box dimer structures via proton-calcium exchange. Incorporation of SA and PEC systems to κ-CAR gels prevented the loss of mechanical strength of the gastric gels due to the ability of κ-CAR to undergo spontaneous gelation in the presence of Na + and K + ions. Binary blends of SA and PEC – Ca 2+ complexed sheared gels with κ-CAR-Ca 2+ gels exerted a significantly lower mechanical strength loss sensitivity against pH and counterion composition of the gastric fluids. [ABSTRACT FROM AUTHOR]

The purpose of this work was to develop a multiparticulate system exploiting the pH-sensitive property and biodegradability of calcium alginate beads for intestinal delivery of ceftriaxone sodium (CS). CS was entrapped in beads made of sodium alginate and sodium carboxymethylcellulose (CMC), acacia, HPMC K4M and HPMC K15M as drug release modifiers. Beads were prepared using calcium chloride as a cross-linking agent, followed by enteric coating with cellulose acetate phthalate (CAP). The beads were then evaluated for entrapment efficiency using HPLC, in vitro drug release examined in simulated gastric fluid (pH 1.2) and simulated intestinal fluid (pH 6.8), swellability, particle size and surface characterization using optical microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). Thermal gravimetric analysis (TGA) was utilized to check the polymer matrix strength and thermal stability. The drug entrapment efficiency of the optimized formulation was determined to be 75 ± 5 %. Swelling properties of drug-loaded beads were found to be in a range of 0.9-3.4. Alginate beads coated with CAP and containing CMC as a second polymer exhibited sustained release. The drug release followed first-order kinetics via non-Fickian diffusion and erosion mechanism. The particle size of the beads was between 1.04 ± 0.20 and 2.15 ± 0.36 mm. TGA, AFM, and SEM data showed composition and polymer-dependent variations in cross-linking, thermal stability, surface structure, morphology, and roughness. The physico-chemical properties of the developed formulation indicate suitability of the formulation to deliver CS orally. [ABSTRACT FROM AUTHOR]

In the present work, 5% (w/w) canola oil-in-water submicron emulsions containing sodium alginate were investigated as β-carotene (0.05% w/w) carriers. O/w emulsions prepared via spontaneous emulsification were Tween-80 (SA, 1 and 1.5% w/w) stabilised. Ionotropic gelation of the o/w emulsions' continuous phase via in situ Ca 2+ release, in the presence (sheared o/g emulsions) or absence (quiescent o/g emulsions) of mechanical stirring (1000 rpm, 6 h) was conducted. β-Carotene chemical stability in both o/w and o/g emulsions following 65 day storage periods at 4, 20 and 37 °C, as well as its bioaccessibility under in vitro oro-gastro-intestinal digestion conditions were evaluated. Oxidative degradation rates of β-carotene ranged from 0.22 to 2.77%/day. Although Ca 2+ -mediated gelation of o/w emulsions’ aqueous phase enhanced β-carotene chemical stability, oxidative degradation rates between quiescent o/g (0.07–1.42%/day) and sheared o/g (0.19–1.50%/day) emulsions were comparable. Based on the activation energies of β-carotene degradation calculated by the Arrhenius kinetic model, sheared o/g emulsions exerted the lowest storage temperature dependency, followed by the quiescent o/g and SA containing o/w emulsions. Moderate (ca. 27%) to high (ca. 48%) bioaccessibility of β-carotene was achieved in quiescent and sheared o/g emulsions respectively, showing no dependency on SA content. Contrarily, β-carotene bioaccessibility was reduced from ca. 29–16% for 1 and 1.5% SA containing o/w emulsions. Digesta micellar fractions of o/g emulsions exerted smaller lipid droplet size and lower surface tension values compared to the SA containing o/w emulsions. Therefore, it was postulated that enhanced β-carotene bioaccessibility in o/g emulsions was associated with their higher colloidal stability throughout gastrointestinal passage. [ABSTRACT FROM AUTHOR]

In the present work, the intragastric structuring ability of o/w emulsions either stabilised (1–4%, w/w of sodium alginate (SA)) or structured with sheared ionic gel (1–3%, w/w of SA crosslinked with Ca 2+ ) in the absence (saliva and gastric phases constituted of deionised water) or presence of in vitro pre-absorptive conditions (physiological simulated saliva and gastric fluids) was investigated. Visualisation of the morphological aspects of the gastric chymes, in the absence of multivalent counterions, demonstrated that SA stabilised systems underwent a remarkable swelling in the pH range of 2–3, whilst at the same pH range, ionic SA gel structured systems maintained their major structure configuration. When the aforementioned systems were exposed to physiological intragastric fluids, a reduction of the length and the hydrodynamic volume of the alginate fibres was detected regardless the structuring approach. On their exposure to physiological intragastric conditions (pH = 2), SA stabilised emulsions underwent sol–gel transition achieving a ca. 3- to 4-order increase of storage modulus (at 1 Hz). In the case of ionic sheared gel structured emulsions, exposure to physiological intragastric fluids resulted in a 10-fold reduction ability of their acid structuring ability, most likely due to the dialysis of egg-box dimer conformations by monovalent cations and protons and the sterical hindering of hydrogen bonding of MM and GG sequences under acidic conditions. Using of non-physiological simulated intragastric fluids was associated with overestimated structuring performance of SA regardless its physical state. [ABSTRACT FROM AUTHOR]

Resveratrol (Res), a polyphenolic phytoalexin, had shown a promising therapeutic efficacy towards treatment of periodontal disease in vitro . This work aims to develop Res microbeads with strong mucoadhesion using thiolated alginate (TA) for local treatment of periodontal pockets. TA was synthesized by conjugating sodium alginate (A) with thioglycolic acid. Product was evaluated by IR and DSC. Both A and A:TA Res microbeads with different ratios were prepared by ionotropic gelation method. Formulations were evaluated regarding their entrapment efficiency (%EE), swelling index (SI), in vitro drug release and kinetics. Selected formula was examined for its mucoadhesion by ex vivo wash-off method, surface morphology using scanning electron microscope (SEM) and stability against light. Clinical evaluation is running.Formation of TA was confirmed. %EE for all formulations ranged from 83.72 to 104.54%. Results revealed a significant lower SI for TA rich formulation (A/TA 1:1) along with slower release rate and zero-order kinetics, in addition to powerful mucoadhesion; 26% remaining of microbeads after 1 h, compared to 2% for A microbeads. SEM micrographs showed a rough surface with drug precipitation. The formula maintained its %EE after 5 h exposure to direct sunlight. A/TA 1:1 mucoadhesive Res microbeads could be exploited as a prolonged drug release devices for intrapocket application. [ABSTRACT FROM AUTHOR]

Context: Gabapentin follows saturation kinetics for absorption because of carrier-mediated transport and narrow absorption window in stomach. There is need to develop a gastroretentive formulation to maximize the absorption without crossing the saturation threshold for absorption. Objective: The aim was to develop a gastroretentive formulation of gabapentin to increase the fraction of drug absorbed in stomach. Materials and methods: Sodium alginate and sodium carboxymethylcellulose were used to formulate the microsphere by ionotropic gelation with calcium chloride. The formulation was optimized using a three-factor, three-level Box-Behnken design. Results: The particle size varied from 559.50 to 801.10 μm, entrapment efficiency from 61.29 to 81.00% and in vitro release from 69.40 to 83.70%. The optimized formulation was found using point-prediction, and formulation OF-3 showed optimum results at 608.21 μm size, 79.65% entrapment efficiency and 82.72% drug release and 81% mucoadhesion up to 10 h. The drug release was controlled for more than 12 h. Discussion: The particle size was most influenced by sodium alginate while entrapment efficiency and drug release depended upon both polymers. The release followed Higuchi model. Conclusion: Gastroretentive formulation was successfully optimized by a three-factor, three-level Box-Behnken design and found to be useful. [ABSTRACT FROM AUTHOR]

Gelatin beads containing a concentrated extract of Roselle ( Hibiscus sabdariffa L.) calyx rich in polyphenolic compounds were coated with sodium alginate and ionotropically gelled using CaCl2. Single-coated beads and double-coated beads were obtained by this technique, and the release pattern of the loaded extract was evaluated. As a result, release pattern of these compounds fits properly to a first-order Weibull distribution equation. The release rate constant decreased linearly with the number of alginate coats and with the increase in immersion time in CaCl2 and the Lag period increased significantly with the number of alginate coats. The release of H. sabdariffa's polyphenols can be well controlled manipulating the number of alginate coats and the immersion time in a CaCl2 solution, allowing not only to control the gastrointestinal segment where they could be released but also to control the release rate with the certainty that the initial concentration will be completely released showing a highly significant antioxidant activity as well. [ABSTRACT FROM AUTHOR]

Controlled release naproxen spheres were prepared in a cross-linked alginate matrix using ionotropic gelation technique. A suspension of naproxen in 1%, 2%, or 3% w/v sodium alginate solution was added drop wise into 2% w/v calcium chloride solution and the resulting spheres were evaluated for their morphology, physical characteristics, rate of swelling, and micromeritics. Increase in concentration of sodium alginate marginally increased particle size of the spheres. The arithmetic-number mean diameter of naproxen-loaded spheres ranged from 1.09 mm for 1% alginate spheres to 1.31 mm for 3% alginate spheres. The encapsulation efficiency increased linearly with increasing alginate concentration (R2 = 0.9996) due to formation of denser spheres. The rate of swelling of the spheres over a 1 h period was about 50% in deionized water and more than 2000% in phosphate buffer solution. The release of naproxen from the spheres studied in phosphate buffer solution (pH 7.4) followed zero-order release kinetics (after the initial burst effect) between 30 and 90 min for 1% and 2% alginate spheres, and between 30 and 120 min for 3% alginate spheres, exhibiting correlation coefficient values ranging from 0.9929 to 0.9999. The rate of release of naproxen decreased with increasing concentration of sodium alginate due to slow penetration of dissolution fluid in the spheres. The results suggest that alginate spheres can potentially deliver naproxen at zero-order controlled release following oral administration. [ABSTRACT FROM AUTHOR]

The present study reports the optimization of sustained release microbeads of aceclofenac sodium were prepared by ionotropic gelation technique, using different variables such as drug-polymer ratios, concentration of cross-linking agent, cross-linking time. The effects of these processing variables were evaluated on physicochemical properties and drug release potential of microbeads. .The shape and surface characteristics were determined by scanning electron microscopy (SEM). While increasing in the concentration of sodium alginate dispersion increased sphericity, size distribution, flow properties, mean particle size, swelling ratio and drug entrapment efficiency. While increasing cross-linking time was significantly decreases the mean particle size. The mean particle sizes of microbeads were found to be in the range 596.45±1.04 to 880.10±0.13μm. The drug entrapment efficiency was obtained in the range of 63.24-98.90%w/v. No significant drug-polymer interactions were observed in FT-IR studies. In-vitro drug release profile of aceclofenac sodium from microbeads was examined in simulated gastric fluid pH1.2 for initial 2h, mixed phosphate buffer pH 6.8 up to 6h and simulated intestinal pH 7.2 at end of 24h. The release of drug from the microbeads was pH dependent, showed negligible drug release in pH1.2. Under neutral conditions the beads will swell and the drug release depend on swelling and erosion process resulting optimum level of drug released in a sustained manner and exhibited zero-order kinetics. Aceclofenac sodium microbeads prepared by ionotropic gelation method using natural polysaccharide like sodium alginate showed a satisfactory sustained release profile and minimizing dose related side effects. The entire process is feasible in an industrial scale and demands pilot study. [ABSTRACT FROM AUTHOR]

Sustained-release polymeric beads containing diclofenac sodium were fabricated with hydrophilic polymers, sodium carboxymethyl cellulose (Na CMC), and sodium alginate (Na alginate). Particulate beads of Na CMC and Na alginate were prepared by the ionotropic gelation method using calcium chloride as a cross-linking agent. Beads of diclofenac sodium were prepared with different concentrations of polymers. Prepared beads were evaluated for their yield, particle size, drug entrapment efficiency, release behavior and tested for the presence of incompatibility using FTIR measurement. The drug entrapment efficiency varied between 73 and 92% in different formulations. For the same concentration of polymer, the release of diclofenac sodium from the beads was observed to be 82.69% and 91.33% for Na CMC and Na alginate, respectively, at the end of 10 h. The drug in beads maintained its identity after bead formation as observed by the FTIR study. From the study it could be concluded that multiparticulate beads of diclofenac sodium could be successfully prepared by the ionotropic gelation technique with high entrapment efficiency and sustained-release characteristics. [ABSTRACT FROM AUTHOR]

Abstract: The present study describes the swelling/degradation behavior of Ba2+ ions-crosslinked sodium alginate/carboxymethyl guar gum bipolymeric beads which are intended to exhibit greater stability in the environment of changing pH along the gastrointestinal (GI) tract. The beads demonstrated pH dependent swelling as they swelled to nearly 56±4% in simulating gastric fluid (SGF) of pH 1.2 while 180±8% water uptake was observed in 6h in simulating intestinal fluid (SIF) of pH 7.4, followed by degradation. When the beads were put in the media of varying pH (to mimic transition from mouth to colon), the beads remained quite stable for nearly 10h and then began to disintegrate. It was found that pre-treatment of beads with 0.1N HCl affected their swellibility. Moreover, on increasing the crosslinking time, the beads demonstrated greater stability but less water uptake. Finally, it was concluded that barium ion-crosslinked bipolymeric beads demonstrate pH-sensitive swelling and are quite stable in the environment of changing pH, thus offering their strong candidature for possible use in oral delivery of drugs along the GI tract. [Copyright &y& Elsevier]

Geopolymer beads are already known as alternative, cost-effective, environmentally friendly adsorbents for cationic species in wastewater treatment. To broaden the spectrum of applications it is necessary to functionalize the geopolymer matrix with fillers and create composites. In this study, being hydrotalcite an anionic exchanger, highly reproducible geopolymer-hydrotalcite hybrid beads were synthesised. Starting from a metakaolin-based geopolymer slurry added with a sodium alginate solution and hydrotalcite powder as filler, millimetre-sized beads were shaped by ionotropic gelation using injection-solidification in CaCl 2 solution. In order to vary the porosity and related properties of the beads, two consolidation methods were adopted: a conventional consolidation in a heater set at 60 °C and a freeze-drying process. Beads differed in terms of dimension and morphology with an open porosity ranging from 50 to 70% and specific surface area from 12 to 23 m2 g−1. Mechanical resistance, following ISO 18591, was about 6 MPa making the beads easy to handle and resistant in the recovery, separation and filtration operations of aqueous systems. [Display omitted] • Geopolymer-hydrotalcite hybrid beads were produced by ionotropic gelation. • Beads were finally consolidated in a heater or by a freeze-drying process. • Highly reproducible beads with different morphology and porosity were obtained. • Beads were easy to handle and resistant, with a compressive strength around 6 MPa. • Composite beads are potentially useful for the removal of different pollutants. [ABSTRACT FROM AUTHOR]

Microencapsulation of lipase from Yarrowia lipolytica IMUFRJ 50682 was performed by ionotropic gelation with sodium alginate. Sodium alginate, calcium chloride and chitosan concentrations as well as complexation time were evaluated through experimental designs to increase immobilization yield (IY) and immobilized lipase activity (ImLipA) using p-nitrophenyl laurate as substrate. To adjust both parameters (IY and ImLipA), the desirability function showed that microcapsule formation with 3.1%(w/v) sodium alginate, 0.19%(w/v) chitosan, 0.14 M calcium chloride, and 1 min complexation time are ideal for maximal immobilization yield and immobilized lipase activity. A nearly twofold enhancement in Immobilization yield and an increase up to 280 U/g of the lipase activity of the microcapsules were achieved using the experimental design optimization tool. Chitosan was vital for the high activity of this new biocatalyst, which could be reused a second time with about 50% of initial activity and for four more times with about 20% of activity. [ABSTRACT FROM AUTHOR]