Gellan Gum Concentration Research Articles

Production of gellan gum using milk skin residue (MSR)—a tea shop waste: statistical optimization and downstream processing

In this work, the production and downstream processing of gellan gum obtained from milk skin residue (MSR) as a carbon source was investigated. The different medium variables, namely shaking speed, inoculum size, and nitrogen source, on gellan gum production were studied. The suitable medium variables were found to be shaking speed (150 rpm); inoculum size (5% v/v), and nitrogen source (yeast extract, YE). The production of gellan gum was compared for various carbon sources, namely fructose, sucrose, glucose, lactose, and MSR. In order to obtain higher gellan gum concentration, response surface methodology was employed for optimizing MSR to glucose ratio, initial pH, and yeast extract concentration. The maximum gellan gum concentration of 8.98 ± 0.42 g/L was obtained at the following optimum conditions: ratio of MSR and glucose = 1:0.743, initial pH (7.5), and yeast extract concentration 8 g/L. The concentration of gellan gum was increased by 2.73-fold than un-optimized medium. The various factors influencing the recovery of gellan gum, namely screening of solvents, ratio of solvent to supernatant (v/v), and incubation time for precipitation, were also studied. The purified gellan gum was characterized by thermogravimetric analysis (TGA/DSC), Fourier transform infrared spectroscopy, scanning electron microscope, and X-ray diffraction analysis.

Optimization of maturation process for somatic embryo production and cryopreservation of embryogenic tissue in Pinus koraiensis

Korean pine broadleaf mixed forests are important for maintaining biodiversity in Northeast China. Excessive harvesting of the Korean pine tree has led to it being listed as an endangered species in China. Somatic embryogenesis technology has the potential to accelerate breeding by improving seedling quality to meet future wood harvesting needs. In addition, rare and valuable germplasm resources can be maintained through the use of cryopreservation. Here, we described the utilization of somatic embryogenesis in Korean pine, with a focus on maturation and cryopreservation. Embryogenic tissues (ETs) were induced from immature seeds collected from open-pollinated sources of Korean pine (28 families). Highest induction percentage of ET reached 22%. The proliferation ability of ET in different cell lines differed. Increasing ABA(up to 80 µM L− 1), gellan gum (up to 12 g L− 1) and sucrose (0.2 m L− 1) concentrations in maturation medium improved the yield of cotyledonary somatic embryo (SE). Maximum yield of cotyledonary SEs (160 SEs g− 1 fresh mass) was obtained following ET dispersion on filter paper discs at low density (50 mg fresh mass). Both the germination percentage of SEs and survival percentage of regenerated plants were about 50%. Moreover, ET began to lose their potential for somatic embryogenesis after 6 months of subculture. ET cultures were cryopreserved, and culture recovery (133 SEs g− 1 fresh mass) was demonstrated after thawing. In this paper we report a significantly improved procedure for generating Korean pine SEs, leading to a high yield of cotyledonary SEs. A cryopreservation protocol for the ET of Korean pine was also established. The present work reports a significantly improved procedure for generating somatic embryos and cryopreservation of embryogenic tissue in Korean pine.

Effect of gellan gum, xylitol and natamycin on Zygosaccharomyces bailii growth and rheological characteristics in low sugar content model systems

This study evaluated the effect of some natural additives and the structure imparted by them on microbial growth and rheological characteristics in acidic model foods with reduced glycidic content. Systems were formulated using gellan gum, as gelling agent; xylitol, as aw depressor; and natamycin, as antimicrobial. Additive-free control systems were prepared. The pH was adjusted to 3.50 or 5.50 as required. Systems were inoculated with Zygosaccharomyces bailii. The effect of additives alone and combined on Z. bailii growth was studied. In some cases, the possible use of additives as yeast nutrients was evaluated. Furthermore, systems rheological characterization was performed. Additives and the structure given by gellan gum significantly affected yeast growth. Gellan gum initially slowed Z. bailii development, but as storage progressed, it acted as yeast carbon source, promoting its growth. A similar trend was observed when xylitol effect was studied. Natamycin inhibited yeast growth in all systems assayed. Additives modified the rheological characteristics of the gels and this effect depended on gellan gum concentration and pH. Obtained results emphasize the importance of considering the different effects that additives and their combinations can exert on the growth of deteriorating microorganisms and on the physical characteristics of gels.

Formulation, Ex-Vivo and Preclinical In-Vivo Studies of Combined pH and Ion-Sensitive Ocular Sustained In Situ Hydrogel of Timolol Maleate for the Treatment of Glaucoma

The aim of the present research work was to develop safe, effective, and stable in situ hydrogel for the ophthalmic drug delivery using the combination of ion-responsive polymer gellan gum and pH-sensitive polymer carbopol 934P to treat glaucoma. Background: Timolol maleate is a BCS class I drug used as the first line of treatment in open-angle glaucoma. The rapid precorneal elimination of conventional formulation containing class I drugs exhibits poor therapeutic effect and bioavailability. So, in situ gelling system was formulated and characterized. Methods: Box-Behnken design was used to statistically optimize the formulation parameters and evaluate the effects of formulation attributes, namely concentration of gellan gum (X1), the concentration of carbopol 934P (X2) and concentration of benzododecenium bromide (X3) on selected critical quality attributes (Y1-Y7). Trial run data were statistically analyzed using the polynomial equation and response surface plots. Optimized formulation was selected based on desirability function, design space, and was further characterized and compared with the marketed formulation. Results: The concentration of both polymers showed a synergistic positive impact on viscosity at the non-physiological and physiological conditions. Trial runs showed controlled drug release with diffusion-controlled mechanism and good mucoadhesive strength due to the presence of Carbopol 934P. The preservative benzododecenium bromide showed the ability to enhance trans-corneal permeation. The optimized formulation has appeared as a clear solution at the non-physiological condition and clear gel at the physiological condition with an acceptable pH range of 5-6. Other quality attributes like rheological properties, gelling capacity, texture analysis, Isotonicity, contact angle, sterility, antimicrobial efficacy, and stability were found in desires values for the ocular application. The safety of in situ gel for human use was confirmed by ocular irritation and histopathology studies in the rabbit eyes. The intraocular pressure (IOP) reduction with optimized formulation was found comparable and less fluctuating compared to ophthalmic gel-forming marketed solution of timolol maleate (TIMOPTIC-XE®). Conclusion: The cross-linking between Carbopol 934P with Gellan gum in the formation showed more viscous gelling at the physiological condition to provide long pre-corneal residence time. The optimized formulation exhibited all the desirable attributes of an ideal ophthalmic in situ gelling formulation, exhibited in-vitro controlled drug release, good gelling capacity, and was found to be stable and non-irritant to the eye.

Effect of hydrogel particle mechanical properties on their disintegration behavior using a gastric digestion simulator

The interest in designing novel foods whose digestibility can be controlled based on life stage and health conditions continues to grow. Physical digestion is important for solid foods as their breakdown and resulting size reduction can promote enzymatic reactions. Our human gastric digestion simulator (GDS) enables the simulation and direct observation of food particle disintegration induced by simulated antrum contraction waves. The objectives of this study were to verify the disintegration performance of the GDS compared with previously reported in vivo data and evaluate the effects of the mechanical properties of hydrogel particles on their in vitro gastric disintegration behavior. Agar beads with four fracture forces were prepared and mixed with meal containing locust bean gum to adjust viscosity same as their in vivo data. The half residence time of intact beads was longer for hard agar beads than for soft agar beads, and a similar disintegration trend to in vivo data was obtained. Moreover, as solid food models, 5-mm hydrogel cubes with different fracture stresses and fracture strains were prepared by varying the agar and native type gellan gum concentrations. The hydrogel cubes disintegrated because of fracture and abrasion during in vitro gastric digestion in the presence of simulated antrum contraction waves. The degree of hydrogel cube disintegration was affected by their fracture strain rather than their fracture stress and was suppressed when their fracture strain was greater than 30%. Our findings may provide a better understanding of the gastric digestion behavior of solid foods with different mechanical properties.

Gellan Gum-Based Hydrogel for the Transdermal Delivery of Nebivolol: Optimization and Evaluation.

Poor solubility and appreciable first-pass metabolism have limited the oral bioavailability of nebivolol. The objective of the current investigation was to design, formulate, and optimize a hydrogel-based transdermal system for nebivolol using factorial design and compare its pharmacokinetics with oral suspension. Hydrogel formulations (F1–F8) were prepared by varying the amounts of gellan gum, carbopol, and polyethylene glycol. A 23 full factorial design was used to assess the effect of independent variables such as gellan gum, carbopol, and polyethylene glycol 400 on dependent variables like viscosity, in vitro release, and ex vivo permeation after 2 h at two levels. Optimized gel (F7), containing nebivolol hydrochloride (75 mg), gellan gum (300 mg), carbopol (150 mg), polyethylene glycol 400 (20 µL), tween 80 (1 mL), ethanol (10 mL), and water (up to 30 mL) was selected and evaluated in albino rats. The physicochemical properties of F7 (pH: 7.1 ± 0.15, viscosity: 8943 ± 116 centipoise, drug content: 98.81% ± 2.16%) seem ideal for transdermal application. It was noticed that the concentration of carbopol has a more significant role than gellan gum in gel viscosity. A biphasic release pattern was exhibited by gels, and the release rate was mainly influenced by the concentration of gellan gum. Greater transdermal flux (30.86 ± 4.08 µg/cm2/h) was observed in F7 as compared with other prepared gels. Noticeable enhancement in AUC0-α value (986.52 ± 382.63 ng.h/mL; p < 0.01) of transdermal therapy (~2-fold higher compared with oral administration) established the potential of F7 to improve the rate and extent of nebivolol delivery. The overall results demonstrated here signify that F7 could be a feasible alternative to oral therapy of nebivolol.

Structure of gellan gum-hydrolyzed collagen particles: Effect of starch addition and coating layer.

In this work, we developed biopolymeric structures, based on electrostatic attraction, through dripping gellan gum into hydrolyzed collagen (HC), to deliver hydrophilic compounds. Moreover, we evaluated the influence of starch addition on the polymeric network as well as the coating effects promoted by an outer gellan layer. The lowest tested gellan gum concentration in the core (0.5% w/w) was the best one to build spherical beads, with high retention of bioactives (>84% for anthocyanin and >68% for HC). Moreover, the minimum HC concentration (2.5% w/w) in the gelling bath allowed the saturation of active sites of gellan gum presented in the core, as regardless of the HC concentration in the peptide bath, particles presented the same amount of adsorbed peptide. Starch disturbed the interactions between HC and gellan, increasing porosity and pore size, but it presented an important role in retaining anthocyanin in the particle's core. Finally, we demonstrated that addition of a gellan coating layer affected the structure of beads: Peptide molecules (positively charged), already adsorbed onto the beads, diffused out of the core, attracted by the negatively charged gellan coating layer. Consequently, it decreased particle size and increased pore size in the outer part of the particles, which was associated with a reduction in the retention of bioactives. These findings bring important contributions to particle engineering: A new process for particle production was proposed, in which hydrogels were produced by dripping the polysaccharide into the protein bath to be externally gelled, without previous crosslinking with salts.

Effective production of keratinase by gellan gum-immobilised Alcaligenes sp. AQ05-001 using heavy metal-free and polluted feather wastes as substrates.

The ability of gellan gum-immobilised cells of the heavy metal-tolerant bacterium Alcaligenes sp. AQ05-001 to utilise both heavy metal-free and heavy metal-polluted feathers (HMPFs) as substrates to produce keratinase enzyme was studied. Optimisation of the media pH, incubation temperature and immobilisation parameters (bead size, bead number, gellan gum concentration) was determined for the best possible production of keratinase using the one-factor-at-a-time technique. The results showed that the immobilised cells could tolerate a broader range of heavy metal concentrations and produced higher keratinase activity at a gellan gum concentration of 0.8% (w/v), a bead size of 3mm, bead number of 250, pH of 8 and temperature of 30°C. The entrapped bacterium was used repeatedly for ten cycles to produce keratinase using feathers polluted with 25ppm of Co, Cu and Ag as substrates without the need for desorption. However, its inability to tolerate/utilise feathers polluted with Hg, Pb, and Zn above 5ppm, and Ag and Cd above 10ppm resulted in a considerable decrease in keratinase production. Furthermore, the immobilised cells could retain approximately 95% of their keratinase production capacity when 5ppm of Co, Cu, and Ag, and 10ppm of As and Cd were used to pollute feathers. When the feathers containing a mixture of Ag, Co, and Cu at 25ppm each and Hg, Ni, Pb, and Zn at 5ppm each were used as substrates, the immobilised cells maintained their operational stability and biological activity (keratinase production) at the end of 3rd and 4th cycles, respectively. The study indicates that HMPF can be effectively utilised as a substrate by the immobilised-cell system of Alcaligenes sp. AQ05-001 for the semi-continuous production of keratinase enzyme.

Temperature and Water Availability During Maturation Affect the Cytokinins and Auxins Profile of Radiata Pine Somatic Embryos.

Somatic embryogenesis (SE) provides us a potent biotechnological tool to manipulate the physical and chemical conditions (water availability) along the process and to study their effect in the final success in terms of quantity of somatic embryos produced. In the last years, our research team has been focused on the study of different aspects of the SE in Pinus spp. One of the main aspects affecting SE is the composition of culture media; in this sense, phytohormones play one of the most crucial roles in this propagation system. Many studies in conifers have shown that different stages of SE and somatic embryo development are correlated with distinct endogenous phytohormone profiles under the stress conditions needed for the process (i.e., cytokinins play a regulatory role in stress signaling, which it is essential for radiata pine SE). Based on this knowledge, the aim of this study was to test the effect of different temperatures (18, 23, and 28°C) and gelling agent concentrations (8, 9, and 10 gL-1) during the maturation stage of Pinus radiata SE in maturation and germination rates. Parallel, phytohormone profile of somatic embryos developed was evaluated. In this sense, the highest gellan gum concentration led to significantly lower water availability. At this gellan gum concentration and 23°C a significantly higher number of somatic embryos was obtained and the overall success of the process increased with respect to other treatments assayed. The somatic embryos produced in these conditions showed the highest concentration of iP-type cytokinins and total ribosides. Although, the different conditions applied during maturation of somatic embryos led to different hormonal profiles, they did not affect the ex vitro survival of the resulting somatic plants, where no significant differences were observed.

Optimization of a novel in situ gel for sustained ocular drug delivery using Box-Behnken design: In vitro, ex vivo, in vivo and human studies

The aim of the present research work was to formulate, optimize and evaluate the in-situ gel for the ophthalmic drug delivery using the combination of gellan gum and carbopol 934P. The Box-Behnken design was applied to optimize the concentration of gellan gum (X1), carbopol 934P (X2) and benzododecenium bromide (X3) to achieve the maximum viscosity [at physiological condition; 35 °C, pH 7.4, and simulated tear fluid (STF)], mucoadhesive strength, permeability coefficient and sustained release of the drug from the gel with constraint on the viscosity under the non-physiological condition (25 °C, pH 5). Response surface plots were drawn, the statistical validity of the polynomials was established, and optimized formulation was selected by the feasibility and grid search. The design proposed the optimized batch by selecting the independent variables as gellan gum (0.55% w/v), carbopol 934P (0.35% w/v) and benzododecenium bromide (0.013% w/v) to achieve the maximum viscosity (3363 cps) at physiological condition, mucoadhesive strength (22.35 dyn/cm2), t90% (1200 min), permeability coefficient (1.36 × 10−5 sq.cm/sec), with minimum viscosity (131 cps) under the non-physiological condition. The combination of gellan gum and carbopol 934P improved the gelation (synergistic effect) characteristics of the in situ gel. The optimized in situ gel was clear, isotonic, pH 4.7 and showed pseudoplastic flow, high in vitro gelling capacity, low contact angle, acceptable hardness (51018 gm), compressibility (64617 gm) and adhesiveness (74 gm) values for the ocular application. The ex vivo study showed the significant protection of the mast cell from the degranulation. The ocular irritation and histopathology studies in the rabbit eyes confirmed the safety of in situ gel for human use. The in vivo drug release studies showed the presence of drug in the rabbit tear fluid up to 3 h in comparison to just 1 h with the eye drop solution. The contact time of the in situ gel in the human eye was 15.0 ± 2.5 min, which was >2 folds higher than the marketed gel (6.0 ± 3.2 min), which could reduce the dosing frequency and total dose of drug. The Box-Behnken design facilitated the optimization of in situ gel for sustained ophthalmic drug delivery.

Preparation of Gellan Gum (GG) Film: The effect of GG, Calcium Chloride (CaCl2), Glycerol Concentration and Heat Treatment

The aim of this work was to investigate the effect of gellan gum (GG), calcium chloride (CaCl2) and glycerol concentration on physical appearance of the film. It was found that, after heated at 50 °C for 24, hours the films were successfully produced using low amount of GG (0.50, 0.75, and 1.00 g) with effective concentration of CaCl2 (5 mM) and glycerol (50 % (w/w)). The film was not well dried at 40 °C while at 70 and 100 °C, the film formed was easily to rupture due to the overheated. At 1.5 g GG the film cannot be produced due to the formation of highly viscos and sticky formulated solution. The effective glycerol concentration was within the range of 30-50 % (w/w, based on GG weight). At 60 and 70 % (w/w) of glycerol, the films started to distort at the edge due to high concentration of the plasticizer.

Low Acyl Gellan Gum as a Gelling Agent in Medium of Saccharomyces Yeasts

Abstract Commercial agar used in microbiological culture has a disadvantage of impurity and opacity. This work aimed to provide an alternative gelling agent to agar and the function of low acyl gellan gum in microbiological culture media was studied. The results showed the texture and water activity of GYGs (glucose-YNB medium containing low acyl gellan gum at different concentrations of 0.3%, 0.6%, 0.9%, 1.2%, 1.5%) were suitable for cultivation of Saccharomyces yeasts. The gelling temperature of GYGs was enhanced with the increased concentration of low acyl gellan gum, while clarity of medium and colony diameter decreased. Scanning electron microscope showed that GYG09 (glucose-YNB medium containing 0.9% low acyl gellan gum) possessed homogeneous porous structures, which was superior to GYA20 with respect to higher clarity and lower dosage of gelling agent when surface plating method was used; however, GYG09 was not suitable for pour plating method.

FORMULATION AND OPTIMIZATION OF THERMOSENSITIVE IN-SITU GEL OF MOXIFLOXACIN HYDROCHLORIDE FOR OCULAR DRUG DELIVERY

Objective: The present study has focused on development and optimization of thermosensitive in-situ ocular drug delivery system for the treatment of conjunctivitis.Methods: Thermosensitive in-situ hydrogel formulation of moxifloxacin hydrochloride was developed by dispensing variable concentration of pluronic F-127, gellan-gum, and carbopol in distilled water. Viscosity, gelation temperature and mean release time (MRT) were measured by using ‘Brookfield' viscometer LV-III (spindle no. 40), rheological techniques and dissolution apparatus respectively. Optimization for ideal formulation was carried by ‘Box–Behnken' design on the basis of prime factors of the formulation including viscosity, gelation temperature, and MRT. Moreover, the optimized formulation was evaluated for accelerated stability study by in vitro drug release, anti-microbial potential by ‘Kirby-Bauer disk diffusion' method and ocular irritancy assay were done by in vivo analysis.Results: Optimised thermosensitive in-situ gel, when administered into cul-de-sac region of the eye, it was immediately transformed from sol to gel by multi-dimensional mechanism due to plurionic, gellan-gum, carbopol. The optimized formulation minimizes the chances of formulation failure as well as the concentration on individual polymer which dependence on a single mechanism of gelation. The final optimised formulation consists of plurionic (11.50% w/v), gellan-gum (0.32% w/v), carbopol (0.3% w/v), shows optimum therapeutic effect. Moreover, the accelerated stability study, anti-microbial potential, and ocular irritancy confirmed the biocompatibility of optimized in-situ drug-containing gel with high potency and stability.Conclusion: Thus, optimized in-situ drug-containing gel with multifactorial approaches showed promising ocular formulation having minimum side effect and high therapeutic efficacy.Â

Enhanced cyanide biodegradation by immobilized crude extract of Rhodococcus UKMP-5M

ABSTRACTThe capability of the crude extract of Rhodococcus UKMP-5M was enhanced by adopting the technology of immobilization. Among the matrices screened to encapsulate the crude extract, gellan gum emerged as the most suitable immobilization material, exceeding the activity of cyanide-degrading enzyme by 61% and 361% in comparison to alginate carrier and non-immobilized crude extract, respectively. Improved bead mechanical strength which supported higher biocatalyst activity by 63% was observed when concentration of gellan gum, concentration of calcium chloride, number of beads and bead size were optimized. The immobilized crude extract demonstrated higher tolerance towards broad range of pH (5–10) and temperature (30°C–40°C), superior cyanide-degrading activity over time and improved storage stability by maintaining 76% of its initial activity after 30 days at 4°C. Furthermore, repeated use of the gellan gum beads up to 20 batches without substantial loss in the catalytic activity was documented in the present study, indicating that the durability of the beads and the stability of the enzyme are both above adequate. Collectively, the findings reported here revealed that the utilization of the encapsulated crude extract of Rhodococcus UKMP-5M can be considered as a novel attempt to develop an environmentally favourable and financially viable method in cyanide biodegradation.

High gellan gum concentration and secondary somatic embryogenesis: two key factors to improve somatic embryo development in Pseudotsuga menziesii [Mirb.

Douglas-fir is a conifer species of major economic importance worldwide, including Western Europe and New Zealand. Herein we describe some characterization and significant refinement of somatic embryogenesis in Douglas-fir, with focus on maturation. The most typical structures observed in the embryonal masses were large polyembryogenic centres (up to 800–1500 µm) with a broad meristem, creating a compact cell “package” with suspensor cells. Singulated somatic embryos composed of both a embryonal head (300–400 µm) and long, tightly arranged suspensor were also frequent. Embryo development was enhanced following embryonal mass dispersion on filter paper discs at low density (50–100 mg fresh mass). Moreover, increasing gellan gum concentration in maturation medium (up to 10 g L−1) improved both the quantity and quality of cotyledonary somatic embryos (SEs), which were subsequently able to germinate and develop into plantlets at high frequency. Embryogenic yield was highly variable among the seven embryogenic lines tested (27–1544 SE g−1 fresh mass). Interestingly secondary somatic embryogenesis could be induced from cotyledonary SEs of both low- and highly-productive lines with some useful practical outcomes: secondary lines from low-performance lines (30–478 SE g−1 fresh mass) displayed significantly higher embryogenic yield (148–1343 SE g−1 fresh mass). In our best conditions, the total protein content in cotyledonary SEs increased significantly with maturation duration (up to 150 µg mg−1 fresh mass after 7 weeks) but remained below that of mature zygotic embryos (300 µg mg−1). The protein pattern was similar in both somatic and zygotic embryos, with major storage proteins identified as 7S-vicilin- and legumin-like proteins.

Quality by design (QbD) approach to formulate in situ gelling system for nose to brain delivery of Fluoxetine hydrochloride: Ex-vivo and In-vivo study

Objective: The purpose of the present study is to develop an ion sensitive in situ nasal gel of Fluoxetine hydrochloride for brain delivery. A 32 factorial design was used to investigate effect of independent variable on dependent variables. Methods: Formulations were evaluated for gelation study, viscosity, gel strength, mucoadhesion strength, drug content, ex-vivo drug permeation, in vivo pharmacodynamic and stability study. Results: The results revealed that as the concentration of gellan gum and HPMC were increased, there was increase in viscosity and mucoadhesive strength and decrease in percent release. The optimized formulation F4 showed highest drug release 94.24 %. In locomotor activity and forced swim test study, the in situ gel treated rats showed significant responses as compared to control group. Histopathological examinations showed no evidence of nasal mucosal damage. The in situ nasal gel was stable after 3 months. Conclusion: It was concluded that, the in situ nasal formulations of Fluoxetine hydrochloride which enhanced nasal absorption and patient compliance for the treatment of depression.

Quality by design (QbD) approach to formulate in situ gelling system for nose to brain delivery of Fluoxetine hydrochloride: Ex-vivo and In-vivo study

Objective: The purpose of the present study is to develop an ion sensitive in situ nasal gel of Fluoxetine hydrochloride for brain delivery. A 32 factorial design was used to investigate effect of independent variable on dependent variables. Methods: Formulations were evaluated for gelation study, viscosity, gel strength, mucoadhesion strength, drug content, ex-vivo drug permeation, in vivo pharmacodynamic and stability study. Results: The results revealed that as the concentration of gellan gum and HPMC were increased, there was increase in viscosity and mucoadhesive strength and decrease in percent release. The optimized formulation F4 showed highest drug release 94.24 %. In locomotor activity and forced swim test study, the in situ gel treated rats showed significant responses as compared to control group. Histopathological examinations showed no evidence of nasal mucosal damage. The in situ nasal gel was stable after 3 months. Conclusion: It was concluded that, the in situ nasal formulations of Fluoxetine hydrochloride which enhanced nasal absorption and patient compliance for the treatment of depression.

Biodegradation of cyanide and evaluation of kinetic models by immobilized cells of Serratia marcescens strain AQ07

Immobilized form of Serratia marcescens strain AQ07 was experimented for cyanide biodegradation. Cyanide degradation (200 ppm) was achieved after 24-h incubation. Three parameters were optimized which included gellan gum concentration, beads size, and number of beads. In accordance with one-factor-at-a-time method, cyanide removal was optimum at 0.6% w/v gellan gum gel, 0.3-cm-diameter beads, and 50 beads number. It was able to withstand cyanide toxicity of 800 ppm, which makes it very suitable candidate in cyanide remediation. Beads reusability indicates one-cycle ability. The first cycle removed 96.3%, while the second removed 78.5%. Effects of heavy metals at 1.0 ppm demonstrated that mercury has a considerable effect on bacteria, inhibiting degradation to 61.6%, while other heavy metals have less effect, removing 97–98%. Maximum specific degradation rate of 0.9997 h−1 was observed at 200 ppm cyanide concentration. Gellan gum was used as the encapsulation matrix. ɤ-picoline-barbituric acid spectrophotometric analytical method was used to optimize the condition in buffer medium integrated with potassium cyanide via one-factor-at-a-time and response surface method. The range of cyanide concentrations used in this research, specific biodegradation rate was obtained to model the substrate inhibition kinetics. This rate fits to the kinetic models of Teisser, Aiba and Yano, which are utilized to elucidate substrate inhibition on degradation. One-factor-at-a-time approach parameters were adopted because it removes more cyanide compared to response surface methodology modules. The predicted biokinetic constant from this model suggests suitability of the bacteria for use in cyanide treatment of industrial waste effluents.

Gellan gum fluid gels for topical administration of diclofenac

Diclofenac topical formulations are often preferred for drug administration to patients who experience serious GIT problems. Absorption of the drug through the skin, however, can be challenging due to the natural protective feature of the stratum corneum (SC). In this article, fluid gels prepared from gellan gum were explored as a topical drug delivery vehicle. Rheological analysis of the formulations showed that it was possible to produce a topical gel with a viscosity and the mechanical strength similar to that of the commercially available Voltaren® gel using 1% w/w of a 50:50 low acyl/high acyl (LA/HA) gellan blend. Soft-tribology was used to assess the lubrication properties of gellan fluid gels. The lubrication of the gellan gum fluid gel formulations at high rubbing speeds was similar to the lubrication of the Voltaren® gel. The use of gellan gum dramatically increased skin permeation of diclofenac when compared with the commercially available formulation and could be controlled by changing the gellan gum concentration and/or sodium ion concentration in the formulation. This study highlights the potential use of fluid gels that can be easily tuned to have physical properties suitable for topical formulations with the added advantage of increasing drug permeation.

Ketoconazole encapsulated in chitosan-gellan gum nanocomplexes exhibits prolonged antifungal activity

The objective of the present study was to prepare ketoconazole loaded chitosan-gellan gum (CSGG) nanoparticles and to evaluate them for antifungal activity against Aspergillus niger. Ketoconazole loaded CSGG nanoparticles were prepared by electrostatic complexation technique using chitosan (CS) as cationic polymer and gellan gum (GG) as anionic polymer with ketoconazole as drug. It was observed that the effect of gellan gum on particle size was more pronounced in comparison to chitosan and increase in its concentration resulted in a significant increase in particle size but decrease in zeta potential. Whereas, increase in concentration of chitosan resulted in increase in zeta potential. The particle size and zeta potential of optimal formulation was 155.7±26.1nm and 32.1±2.8mV which obtained at concentration of chitosan (0.02% w/v) and gellan gum (0.01% w/v). On comparative evaluation, ketoconazole loaded CSGG nanoparticles showed significantly higher antifungal activity against Aspergillus niger than dummy CSGG nanoparticles (without drug) and drug individually.