Alginate Concentration Research Articles

Polyethylene microplastics increase extracellular polymeric substances production in aerobic granular sludge

Wastewater treatment plants act as microplastic (MPs) sinks and secondary MP pollution sources. Little is known about the effect of MPs on biomass and the efficiency of biological wastewater treatment. This study assessed the impact of polyethylene (PE) MPs concentrations (1, 10, 50 mg/L) in wastewater on biological conversions and extracellular polymeric substances (EPS) production (including alginate) in aerobic granular sludge (AGS). PE MPs did not worsen the efficiency of biological treatment but stimulated the production of EPS and alginate in AGS. The alginate content increased from 238.7 ± 4.4 mg/g MLSS in control to 441.6 ± 13.8 mg/g MLSS at the highest PE load in wastewater. The presence of MP changed AGS morphology and worsened the settling properties of biomass, causing biomass washout from the reactors. At the highest PE load in wastewater, the biomass concentration in the reactor effluent was over 2.8 times higher than in the control.

CaCO3 loaded lipid microspheres prepared by the solid-in-oil-in-water emulsions technique with propylene glycol alginate and xanthan gum.

Calcium carbonate (CaCO3) is difficult to deliver in food matrices due to its poor solubility. In this work, CaCO3 powders were encapsulated into Solid-in-Oil-in-Water (S/O/W) emulsions to fabricate delivery systems. The impact of the concentrations of propylene glycol alginate and Xanthan gum (PGA-XG) complexes on the physical stability and structural characteristics of S/O/W calcium-lipid emulsions microspheres were studied. The S/O/W calcium-lipid emulsions were characterized by the particle size, zeta potential, physical stability, and apparent viscosity. The S/O/W calcium-lipid emulsion has higher physical stability (including 6-week storage at 4°C), smaller mean particle size (7.60 ± 1.10 μm), and higher negative zeta-potential (45.91 ± 0.97 mV) when the concentration of PGA-XG complexes was 0.8 wt%. Moreover, Confocal laser scanning microscopy (CLSM) images confirmed that the CaCO3 powders were encapsulated in the O phase. Transmission electron microscopy (TEM) showed that S/O/W calcium-lipid emulsion was spherical. The X-ray diffraction (XRD) analysis further confirmed that CaCO3 was loaded in the S/O/W calcium-lipid emulsion as an amorphous state. The formation mechanism of S/O/W calcium-lipid microspheres was studied by Fourier transform infrared spectroscopy (FTIR) and Raman spectrum analysis. This study provided new ideas that accelerate the creation of a novel type of calcium preparation with higher quality utilization.

Centrifugally spun alginate-poly(lactic acid) microbeads: A promising carrier for drug delivery and tissue engineering

A facile and high yield centrifugal spinning technique known as Forcespinning® (FS) was used to develop unique microstructures consisting of PLA microbeads along alginate fibers. Morphological variation and structural features appeared in the field-emission scanning electron micrographs for the PLA-alginate composites and dried PLA-alginate films from precursor emulsions at constant PLA and varied alginate contents. Shrunk and deflated microbeads were observed for composites whilst spherical beads were evident for the PLA control. Furthermore, PLA was found surrounding the alginate when the alginate was present at 0.24 wt% or lower, while alginate (mushroom-like structures), were seen protruding through the PLA layer at ≥0.34 wt% alginate. Rheological characterization of the composite emulsions revealed that the filler (alginate) provided shear thinning properties including pseudoplasticity, desirable for printing and other related applications in contrast to the Newtonian flow shown by the PLA control. Along with infra-red spectroscopy, the nanocomposites were further characterized using thermal gravimetry and differential scanning calorimetry featuring reversible events influenced by heat capacity and irreversible kinetic/thermodynamic counterparts. The work provides a comprehensive investigation of biocompatible networks of PLA-alginate microbeads embedded in nano-sized fibers and the prospective application of these microbeads as a drug delivery system.

‘Efficacy of sodium alginate, xanthan gum, and diatomite admixtures in improving the strength and shrinkage behaviour of EPS lightweight concrete’

The aim of this study is to demonstrate the effectiveness of cement admixtures in improving the shrinkage and strength resistance of EPS lightweight concretes (ELCs). A group of EPS mixtures containing 0.5, 1 and 2% of sodium alginate, 0.1, 0.3 and 0.5% of xanthan gum and 2, 5 and 8% of diatomite was used. The results of the study showed that increasing the dose of each admixture significantly improved the strength and shrinkage resistance of ELC. Although the application of sodium alginate, xanthan gum and diatomite as cement admixtures decreased the water loss ratio of EPS concrete compared to the reference mix, the increase in their contents increased the water loss ratio of EPS concrete. The increase in sodium alginate, xanthan gum and diatomite content improved the EPS concrete pore structure stability and performance of the interface of transition zones (ITZ) between the cement slurries and EPS aggregates, which had a positive role in improving the strength and shrinkage behaviour of ELC. Application of 2% sodium alginate, 0.5% of xanthan gum and 8% of diatomite can be recommended as the preferred dose of cement admixtures to improve the strength and shrinkage performance of ELC.

Delivery system for grape seed extract based on biodegradable pectin-Zn-alginate gel particles

Pectin-Zn-alginate gel particles from callus culture pectin with increased linearity and decreased rhamnogalacturonan I branching and degree of methylesterification had a higher gel strength and encapsulation capacity. An increase of the alginate concentration led to an increase in the particle gel strength. The grape seed extract (GSE) loaded and empty particles swelled slightly in the simulated gastric fluid (SGF) and gradually in the intestinal (SIF) fluid. The swelling degrees of the GSE-loaded and empty particles in the simulated colonic fluids (SCF) were decreased in the range SCF-7.0 (pH 7.0 + pectinase) > SCF-5.3 (pH 5.3 + pectinase) > SCF-2.3 (pH 2.3 + pectinase). The FTIR spectra indicated that GSE was embedded in the composite particles. Negligible leakage of GSE in SGF was shown. The increase in GSE release in SIF was due to the decrease in particle gel strength and increased swelling degree. The GSE release in fluids simulating the colon inflammation (SCF-2.3 and SCF-5.3) was similar, and it was lower than that in the SCF-7.0 simulating a healthy colon due to the increased gel strength. The percentage release of GSE increased slightly after exposure to different pH. Pectin-Zn-alginate hydrogel systems may be promising candidates for colon-targeted GSE delivery systems.

Effect of sodium alginate on the properties of microbial repair materials and its repair effect on mortar crack

In recent years, microbial repair materials have received widespread attention for their advantages such as stable products and good compatibility with cementitious materials. However, the current construction process of microbial repair materials is mainly by immersion, which limits the more widespread application. Therefore, this study proposed a coating construction process with sodium alginate as the carrier. The effects of sodium alginate concentration and dosing on the fundamental properties of microbial repair materials (CaCO3 content, mechanical properties, water absorption ratio, and heating shrinkage rate) and their effects on mortar repair effects (macroscopic morphology and surface water absorption ratio) were investigated. The repair effects were further verified by combining thermogravimetric analysis of repair products and scanning electron microscopy. The results showed that 1) the microbial repair material had better basic properties when sodium alginate solution with a mass concentration of 1.5% was used, and its solution-to-bacterial solution volume ratios were 8:2, 7:3, and 6:4; 2) using the coating technique, the microorganisms were fixed in the cracks on the mortar surface by using sodium alginate as the carrier. Only twice of repair could generate a mixture of calcium alginate and calcium carbonate crystals in the cracks by close adhesion. The surface water absorption of the repaired specimens was 67% lower than before the repair, which is a significant effect of the repair.

Encapsulation of Mesona chinensis Benth Extract in Alginate Beads Enhances the Stability and Antioxidant Activity of Polyphenols under Simulated Gastrointestinal Digestion.

The aim of this study was to investigate the stability and antioxidant activity of the polyphenols from Mesona chinensis Benth extract (MCE) and its alginate-based encapsulation by extrusion technique during simulated gastrointestinal digestion. The encapsulation efficacy ranged from 41.1 ± 4.7 to 56.7 ± 3.4% with different concentrations of MCE (50–75% v/v), sodium alginate (1.2–1.8% w/v), and CaCl2 solution (3–5% w/v). The optimal condition for MCE-loaded alginate beads (MCB) was composed of 75% MCE, 1.5% alginate, and 3% CaCl2 solution, which provided the highest encapsulation efficiency with a spherical structure and a mean particle diameter of 1516.67 ± 40.96 μm. Fourier transform infrared spectroscopy (FT-IR) reported no chemical interaction between alginate and MCE. The release of total phenolic content (TPC) was only 8.9% after placing MCB in water for 4 h. After simulated digestion, changes in TPC and ferric reducing antioxidant power (FRAP) of MCE significantly decreased by 25.0% and 29.7%, respectively. Interestingly, the incorporation of MCB significantly increased TPC and FRAP in the digesta compared to those of MCE during gastrointestinal tract conditions. The findings suggest that the encapsulation of MCE with alginate as a carrier helps to improve the bioaccessibility and biological activity of M. chinensis polyphenols.

Encapsulation of Salmonella phage SL01 in alginate/carrageenan microcapsules as a delivery system and its application in vitro.

Phages can be used successfully to treat pathogenic bacteria including zoonotic pathogens that colonize the intestines of animals and humans. However, low pH and digestive enzyme activity under harsh gastric conditions affect phage viability, thereby reducing their effectiveness. In this study, alginate (ALG)/κ-carrageenan (CG) microcapsules were developed to encapsulate and release phage under simulated gastrointestinal conditions. The effects of ALG and CG concentrations on the encapsulation and loading efficiency of microcapsules, as well as the release behavior and antibacterial effects of microcapsules in simulating human intestinal pH and temperature, were investigated. Based on various indicators, when the concentration of ALG and CG were 2.0 and 0.3%, respectively, the obtained microcapsules have high encapsulation efficiency, strong protection, and high release efficiency in simulated intestinal fluid. This effect is attributed to the formation of a more tightly packed biopolymer network within the composite microcapsules based on the measurements of their microstructure properties. Bead-encapsulation is a promising, reliable, and cost-effective method for the functional delivery of phage targeting intestinal bacteria.

Production and immobilization pectinase from Bacillus sp. 2P11 using alginate beads

Abstract. Utami AP, Fahrurrozi, Meryandini A. 2022. Production and immobilization pectinase from Bacillus sp. 2P11 using alginate beads. Biodiversitas 23: 3960-3966. Pectinase is one of the enzymes often used in the industrial sector, especially in the food industry, such as extracting and clarifying juices. Previous studies have obtained pectinolytic microbial cultures of Bacillus sp. 2P11 isolated from cocoa beans. Pectinase production using pure pectin substrates such as citrus pectin or pectin from apples costs a lot because these pectins are expensive. Liquid substrate from cocoa pods TSH 858 and ICS 60 with a concentration of 10% is a good amount for pectinase production, and the percentage of total pectin from cocoa pods is 0.823%. The amount of activity of crude extract of pectinase enzyme is 416,780 mU/mL. Precipitation with ammonium sulfate and dialysis increased pectinase activity by 452,335 mU/mL and 586.88 mU/mL, respectively. Enzymes can be used repeatedly with enzyme immobilization. In this study, the immobilization of the enzyme entrapment method with sodium alginate and CaCl2 was designed with the response surface method. The optimum concentration of sodium alginate was 0.5% and 0.3 M CaCl2, with the percentage of an immobilized enzyme at 40.782%. Stability and repeated use of immobilized pectinase can be done up to 5 times.

Pickering emulsion hydrogel based on alginate-gellan gum with carboxymethyl chitosan as a pH-responsive controlled release delivery system

Pickering emulsion hydrogels (PEHs) were developed as a pH-responsive, controlled-release delivery system to address the limitations of Pickering emulsions in some harsh processing or gastrointestinal conditions. Specifically, the PEHs were fabricated based on alginate and various concentrations of gellan gum (GG) with carboxymethyl chitosan (CMCS) matrix. The encapsulation efficiency (EE), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) results proved the successful encapsulation. Furthermore, the hydrogels remained stable in the presence of destabilizing ions (Na+ or phosphate ions) and high osmotic pressure mediums. The texture profile analysis (TPA) characteristics and Young's modulus of the 0.8 % GG (w/v) PEHs were superior to the others. The PEHs prevented the emulsions from being released at pH 2.0, while the emulsions were entirely released at pH 7.4 in vitro, with the rate of release controlled by CMCS and the degree by GG concentration. This work facilitates the delivery of Pickering emulsions with excellent stability and pH-responsive controlled release for hydrophobic actives in food applications.

Alginate-reinforced poly(3-hydroxybutyrate)/ poly(hydroxybutyrate-co-hydroxyvalerate) aerogel monoliths fabricated by phase separation as environmental floating adsorbents

Poly(3-hydroxybutyrate) (PHB)/poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) aerogel monoliths were prepared via nonsolvent induced phase separation and then sequentially immersed in ethanol and sodium alginate (ALG) solutions. The resulting composite aerogels contained up to a 52 wt% fraction ALG, causing a remarkable increase in their compressive modulus and collapse strength from 0.3 MPa and 33 kPa to 4 MPa and 406 kPa, respectively, i.e., by 13/12 times. An increase in the ALG contents in the composite aerogels allowed them to effectively adsorb both water and soybean oil, according to pseudo-second-order adsorption kinetics. The highly porous composite aerogel acted as an efficient floating adsorbent for a cationic dye (i.e., methylene blue (MB)) in water. MB adsorption was found to be strongly dependent on ALG contents in the adsorbent, as well as operating parameters such as the initial concentration, pH, and temperature of MB solutions. MB adsorption is best described by the Langmuir isotherm and follows pseudo-second-order kinetics. Ca2+-crosslinking of ALG further increased compressive strength but significantly decreased MB adsorption capability following pseudo-first-order kinetics, implying a slow internal diffusion step for MB adsorption due to its tightened network structure relative to noncrosslinked adsorbents.

Fabrication and characterization of phycocyanin-alginate-pregelatinized corn starch composite gel beads: Effects of carriers on kinetic stability of phycocyanin

Composite gel beads using calcium alginate and different concentrations of pregelatinized corn starch (PCS) were produced to encapsulate phycocyanin (PC). Rheological properties of different sodium alginate/PCS/PC mixtures, structural and morphological properties of beads, and kinetic stability of encapsulated PC (upon heating at various time-temperature combinations) were then assessed. Rheological properties of the mixtures exhibited shear thinning behaviors. Aquagram revealed that the PC-containing beads had more water structure with weak‑hydrogen bonds. Morphological images represented less subsidence in the structures of composite gel beads, unlike PCS-free beads. Kinetic study showed that degradation rate constant values of PC encapsulated in composite gel beads (1.08–3.45 × 10−4, 3.38–4.43 × 10−4, and 5.57–15.32 × 10−4 s−1) were lower than those in PCS-free alginate gel beads (4.45 × 10−4, 9.20 × 10−4, and 18.04 × 10−4 s−1) at 40, 50, and 60 °C, respectively. This study suggests that the composite gel beads can improve PC stability.

Millifluidic-assisted ionic gelation technique for encapsulation of probiotics in double-layered polysaccharide structure

A unique double-layered vehicle was fabricated for the first time based on a millifluidic/direct gelation to encapsulate probiotics. Free probiotic bacteria are usually very sensitive to severe gastrointestinal conditions and maintaining their survival when passing through the digestive tract is essential. The effects of alginate concentration (20–30 g/L), flow rates of alginate (0.8–1.2 mL/min), and W/O emulsion (0.5–0.7 mL/min) on encapsulation efficiency (EE), size, and sphericity of core–shell millicapsules were optimized for encapsulation of Bifidobacterium animalis subsp. lactis and Lactobacillus plantarum. The optimized calcium-alginate millicapsule was spherical (0.97 ± 0.01 SF), with an average diameter of 4.49 ± 0.19 mm, and encapsulation efficiency of 98.17 ± 0.5 %. Two strains were encapsulated separately in W/O emulsion as a core of the millicapsule. After coating with chitosan, the encapsulation yield of the bacteria, survival rates under simulated gastrointestinal (GI) conditions, and viability during storage were determined. Survival efficiency of B. animalis subsp. lactis and L. plantarum after millifluidic encapsulation were found to be 92.33 and 90.81 %, respectively. Cell viability of encapsulated probiotics after passing through the GI system was improved (7.5 log CFU mL−1 for both strains). Although the viability of the encapsulated probiotics stored at −18 °C for five months significantly decreased (p<0.05), the number of live cells was approximately in accordance with the standard definition of long-term probiotic survival (6 log CFU/g). This work provides a pathway for the construction of an innovative delivery system with high efficiency and protective effects for probiotics.

Phosphorous remediation using alginate/glomalin biobeads: Examining structural cohesivity, nutrient retention, and reapplication viability

Excess nutrient loading from agriculture and urban runoff into limnetic and marine ecosystems is associated with harmful algal blooms that result in eutrophication. Sequestration of nutrients such as phosphorus (P) and nitrogen (N) from agricultural outflows and recycling them as soil amendments would be an environmentally and economically sustainable strategy to alleviate this problem. This study explored the use of biobeads constructed with phytoplankton, Chlorella vulgaris, alginate and glomalin as a possible medium for a cyclic culture-harvest-reapply (CHR) system to address the problem of eutrophication. These “biobeads” were constructed from different concentrations of sodium alginate, C. vulgaris, and glomalin. Bead vitality was evaluated by introducing C. vulgaris to both eutrophic (phosphate ∼1.5 ppm) and hypereutrophic (phosphate ∼4.0 ppm) solutions and measuring phosphate removal. After 9 days in the eutrophic solution, biologically active groups reduced orthophosphate concentrations by an average of 1.35 ppm (80%). In the hypereutrophic solution, an average of 1.52 ppm total phosphate removal (38%) was observed over 5 weeks. The addition of glomalin in high concentrations increased the structural cohesivity of the hydrogel matrix, while low concentrations had an inverse effect. Reapplication of these biobeads to topsoil did not reduce plant growth or plant health parameters. These data suggest that glomalin, in appropriate proportions, is a suitable secondary scaffolding for a sodium alginate hydrogel immobilization medium. The alginate beads of immobilized C. vulgaris could be a promising treatment technique for phosphorus-containing urban wastewater. Further research is warranted to assess long-term impacts on nutrient dispersal and soil quality upon reapplication.

Design and Optimization of Floating Microspheres Using Abelmoschus esculentus Natural Polymer

The main objective of the present research study was to fabricate Vildagliptin floating microspheres by ionotropic gelation using natural polymer, Abelmoschus esculentus obtained from the fruits of Abelmoschus esculentus in combination with sodium alginate. Microspheres were prepared and optimized using central composite rotatable design model using design expert software version 12 .The study is focussed on the interaction effects of the three independent variables, natural polymer concentration, sodium alginate concentration and crosslinker concentration, optimization of formulations response surface methodology was used . drug –excipient compatibility studies were carried out by infrared spectroscopic studies. Infrared spectroscopic studies clearly shown that drug and excipients were compatible. Totally 15 formulations were generated taking 8 factorial points, 6 axial points and 1 centre point. Response surface methodology was used to optimize the formulations. To investigate the responses %cumulative drug release, floating time and floating lag time Response surface methodology was used Polynomial equations and model plots of 3 dimensional model surface plots were generated. Vildagliptin optimized microspheres were formulated and a second order, model quadratic model was used to study influence of formulation factors on response variables. Experimental data of Statistical analysis exhibited good coefficient of regression for cumulative in vitro drug release Regression F –ratios for the experimental variables were significant. The experimental values and predicted values are agreed. All fifteen formulations exhibited % yield of 94.35-99.99%, particle size of 124-441µm, %swelling index 64.52-89.65%, floating time of 10.16 to 13.16 and floating lag time of 30.31 to 46.98 sec. F4 formulation is optimized based on cumulative % in-vitro drug release at 2nd hour, 12th hour, floating lag time and floating time values. Predicted and observed results are in agreement 95% confidence intervals. Based on investigation, RSM is the good tool for optimization of formulations.

A clamp-free micro-stretching system for evaluating the viscoelastic response of cell-laden microfibers

Viscoelastic hydrogel microfibers have extensive applications in tissue engineering and regenerative medicine, however, their viscoelasticity is still difficult to be directly characterized because microfiber-specific measuring system is lacking for quantitative studies. In this paper, we develop a two-probe micro-stretching system to quantitatively investigate viscoelasticity of the microfiber by evaluating the storage and loss modulus: E′ and E″. A liquid bridge-based fixation method enables single microfiber to be easily fixed to be stably stretched by a two-probe actuator. Afterward, multi-frequency stretching force loading is automatically implemented based on real-time force control, and the resulting stress and strain in the frequency spectrum are measured to evaluate the E′ and E″ of pure GelMA, alginate-GelMA composite and GelMA core-alginate shell microfibers. The measured E′ and E″ are verified by the response of NIH/3T3 fibroblast cells to the composite microfibers with different alginate concentrations. Moreover, benefiting from the low-damaged stretching process, our system can also detect the difference of the E′ and E″ between two cellular processes including growth and differentiation of the aligned mesenchymal stem cells in the same one core-shell microfiber. These results all show that our proposed system provides a valuable reference tool for biomaterials design, the study of cell-matrix interaction and disease etiology from the perspective of mechanics.

Optimization of co-encapsulation of L. plantarum cells and Silybum marianum seed extract and evaluation of protective effect of extract on cells survival in simulated gastrointestinal fluids

In the present study, Lactobacillus plantarum (MT, ZH593) native cells and Silybum marianum seed extract (SMSE; rich in antioxidant) were co-encapsulated in alginate microbeads by the internal gelatinization emulsion method. The effects of different concentrations of sodium alginate, SMSE and CaCl2 on microbead characteristics were optimized. Under optimum conditions small spherical microbeads (161.82 ± 13.4 μm) with the highest cell encapsulation efficiency (79.84 ± 4.07%) were produced and the highest antioxidant activity (51.92 ± 2.14%) was obtained. The results showed that the co-encapsulation of L. plantarum with SMSE significantly (P < 0.05) increased the viability of cells (approximately 0.71 log CFU/mL) and the release of the extract (approximately 9–10%) in gastric simulation and intestinal simulation fluids, respectively, when compared with microencapsulation without SMSE addition. Also, microbeads coating with whey protein isolate (WPI; 2.76%) resulted in the higher protection in simulated gastrointestinal fluids than coating with chitosan. The results of this study indicated that the WPI-coated alginate microbeads were a good carrier matrix for the controlled delivery of SMSE (as a new non-carbohydrate prebiotic compound) and increased the viability of L. plantarum in the lower part of the gastrointestinal tract.

CHARACTERIZATION OF NANO PARTICLES ETHANOL EXTRACT OF GUAVA (PSIDIUM GUAJAVA) FRUIT WITH VARIATION OF CHITOSAN-ALGINATE

The ethanol extract of Guava (Psidium Guajava) fruit is known to have strong antioxidant activity so that it has the potential to be developed into a nanoparticle delivery system. The purpose of this study was to determine the effect of variations in the concentration of chitosan - alginate polymer on the physical characteristics of guava fruit extract nanoparticles (Psidium Guajava). Guava Fruit Extract was formulated in the form of nanoparticles by ionic gelation method with variations in the concentration of chitosan:alginate polymer, namely 0.5% : 0.5% (F1), 0.75% : 0.5% (F2), and 1% : 0.5% (F3). The test parameters include the percentage of transmittance. The optimal formulation is based on the level of clarity of the solution and the percentage of transmittance obtained in the formulation ratio of 0.75%: 0.5% (F2), with an average transmittance of 91.9%. Based on the results of the research that has been done, it can be concluded that guava fruit extract can be formulated in nanoparticle size with varying physical characteristics depending on the concentration of chitosan and alginate used.

Utilization of freeze thaw process for polyvinyl alcohol/sodium alginate (PVA/SA) hydrogel composite

Polyvinyl alcohol/sodium alginate (PVA/SA) hydrogel was successfully prepared by freeze thaw process. Without crosslinking agent, hydrogel was formed by using 3, 5 and 7 consecutive cycles of freeze thaw. Hydrogel can be formed by hydrogen bonding formation between OH-group of sodium alginate and polyvinyl alcohol throughout network. Scanning electron microscope reported that microstructure of hydrogel was well packed. The interconnect porosity was also observed. Differential scanning calorimetry exhibited that two exothermic peaks at temperature of 110℃ and 225℃ were observed due to evaporation of water molecule and melting temperature of hydrogel, respectively. The swelling behavior was rapidly increased within initial stage and then it was dimensionally stable. With low sodium alginate content, tensile strength was slightly superior, whereas low in vitro degradation behavior was observed. It was remarkable to note that polyvinyl alcohol/sodium alginate (PVA/SA) hydrogel exhibited outstanding properties for being as a medical material.

Response Surface Methodology for Optimization of Buspirone Hydrochloride-Loaded In Situ Gel for Pediatric Anxiety.

The purpose of the current investigation was to formulate, assess, and optimize oral in situ gels of buspirone hydrochloride (BH) with the specific end goal of expanding the time the medication spends in the stomach, thereby ensuring an extended medication discharge. This would allow the use of a once-a-day dose of liquid BH formulations, which is ideal for the treatment of pediatric anxiety. In situ gels loaded with BH were prepared using various concentrations of sodium alginate (Na alg.), calcium chloride (CaCl2), and hydroxypropyl methylcellulose (HPMC K15M). The in situ gels exhibited the desired consistency, drug distribution, pH, ability to form gel, and prolonged drug release in vitro. The (33) full factorial design was utilized for the revealing of the ideal figures for the selected independent variables, Na alg. (X1), HPMC (X2), and CaCl2 (X3) based on measurements of the viscosity (Y1) and percentage drug release after 6 h (Y2). A pharmacokinetic study of the optimum formulation on rabbits was also performed. The formulation containing 2% of Na alg., 0.9% of HPMC-K15M, and 0.1125% of CaCl2 was selected as the ideal formulation, which gave the theoretical values of 269.2 cP and 44.9% for viscosity and percentage of drug released after 6 h, respectively. The pharmacokinetic study showed that the selected oral Na alg. in situ gel formulation displayed a prolonged release effect compared to BH solution and the marketed tablet (Buspar®), which was confirmed by the low Cmax and high Tmax values. The optimum oral Na alg. in situ gel showed a 1.5-fold increment in bioavailability compared with the drug solution.