Hydroxypropyl Methylcellulose Concentration Research Articles

Effect of hydroxypropyl methyl cellulose on coarse tailings cemented backfill: Rheology, stability, strength and microstructure

The bleeding and segregation of coarse tailings cemented backfill (CTCB) seriously affect the effect of roof-contacted filling, and may even lead to safety hazards in mining. The incorporation of hydroxypropyl methyl cellulose (HPMC) may be an effective solution, but its impact on the performance of CTCB and its underlying mechanism remains inadequately understood. This study comprehensively evaluates the rheology (static and dynamic yield stress, and plastic viscosity), stability (bleeding and permeability), strength, and microstructure of containing HPMC. In addition, the mechanism of HPMC on CTCB was further investigated. The research results show that a certain amount of HPMC (<0.1%) can significantly reduce the dynamic and static yield stress of fresh CTCB, while the plastic viscosity increases with the HPMC content. Furthermore, HPMC can significantly improve the bleeding and segregation of CTCB through association and network structure effects. Finally, HPMC delays the hydration of cement, resulting in an early strength reduction of CTCB, but it has little impact on the strength at 28 days.

Drying kinetics modeling of hot air drying of emulsion templated oleogels employing hydroxypropyl methylcellulose as structuring agent

This work focused on the drying of O/W emulsions employed to obtain templated structured oils with hydroxypropyl methylcellulose (HPMC) as oleogelator. Sunflower oil/water emulsions with different HPMC content (1%–3% w/w) were dried at different air temperatures (from 70 to 100 °C) employing two different initial thicknesses (0.25 and 0.50 cm). Drying kinetics showed the existence of an initial constant drying rate period followed by a falling drying rate period below critical moisture content. This critical content was constant (0.38 kg water/kg dry solid) independently of drying conditions and HPMC content. Drying rate decreased linearly with moisture content during the falling rate periods. A 3-parameter model was proposed to simulate drying kinetics in the range of drying temperature and HPMC content of tested oleogels. Physical properties of fresh and stored (20 days) oleogels such as oil binding capacity, color, and hardness were measured to evaluate drying conditions effect on product quality. Temperatures above 70 °C were necessary to promote the HPMC gelation. Best characteristics of oleogels in terms of texture, color and oil binding capacity were obtained with HPMC content of 2% w/w, 0.25 cm of emulsion thickness and 80 °C of drying temperature. These results are useful for the design of large-scale dryers for this new kind of products.

Optimization of Hydroxypropyl Methylcellulose (HPMC) and Carbopol 940 in Clindamycin HCl Ethosomal Gel as Anti-acne

Clindamycin HCl has anti-acne properties because it can inhibit the growth of Propionibacterium acnes (P. acnes) bacteria. However, the bioavailability of clindamycin HCl is less than 13% of the given dose, so it needs to be developed in the form of ethosomes to increase its bioavailability. This study aimed to create a clindamycin HCl ethosomal gel preparation with varying hydroxypropyl methylcellulose (HPMC) and carbopol-940 as a gelling agent using a factorial design to obtain 4 formulas. The concentrations of HPMC and carbopol 940 used were 0.5% and 1%. The optimum formula was determined based on the pH response, viscosity, spreadability, and adhesion of the clindamycin HCl ethosomal gel preparation. Based on the factorial design analysis, HPMC and Carbopol-940 have an influence on the pH response and adhesion, while the interaction between HPMC and Carbopol-940 influences the spreadability and viscosity responses. The optimum formula was obtained with a desirability value of 0.994 at a concentration of HPMC was 1%, and Carbopol 940 was 0.5%. The minimum inhibitory concentration of the optimum clindamycin HCl ethosomal gel was 60 µg/mL. So, the clindamycin HCl ethosomal gel had a strong antibacterial activity.

The effect of hydroxy propyl methyl cellulose on emulsion stability and sensory properties of virgin coconut oil mayonnaise

Mayonnaise is a semi-solid emulsion made by mixing ingredients such as vegetable oil, egg yolks, and other food ingredients with or without adding food additives, such as stabilizers. This research aimed to study the effect of hydroxypropyl methylcellulose (HPMC) on the emulsion stability and sensory properties of mayonnaise made from virgin coconut oil. In this study, the treatment was the addition of HPMC, namely MV1 (0%), MV2 (2%), MV3 (3%), MV4 (4%), and MV5 (5%), into the mayonnaise formulation. The data obtained were analyzed statistically using analysis of variance and continued with DNMRT at the 5% level. The analysis of variance showed that the HPMC concentration significantly affected emulsion stability, viscosity, degree of acidity, and sensory test of thickness but had no significant effect on the aroma, color, and taste of the mayonnaise. The best treatment was MV5 (5% HPMC), which had 100% emulsion stability, 70119.33 cP viscosity, 5.07 pH on day one, and 99.37% emulsion stability, 69047.33 cP viscosity, and 4.87 pH on day 15. The MV5 mayonnaise was yellowish, had a coconut taste, was slightly rancid, and was thick. The MV5 mayonnaise was more favorable than other treatments regarding the aroma, color, and taste of the mayonnaise.

Comparing the Performance of Raman and Near-Infrared Imaging in the Prediction of the In Vitro Dissolution Profile of Extended-Release Tablets Based on Artificial Neural Networks.

In this work, the performance of two fast chemical imaging techniques, Raman and near-infrared (NIR) imaging is compared by utilizing these methods to predict the rate of drug release from sustained-release tablets. Sustained release is provided by adding hydroxypropyl methylcellulose (HPMC), as its concentration and particle size determine the dissolution rate of the drug. The chemical images were processed using classical least squares; afterwards, a convolutional neural network was applied to extract information regarding the particle size of HPMC. The chemical images were reduced to an average HPMC concentration and a predicted particle size value; these were used as inputs in an artificial neural network with a single hidden layer to predict the dissolution profile of the tablets. Both NIR and Raman imaging yielded accurate predictions. As the instrumentation of NIR imaging allows faster measurements than Raman imaging, this technique is a better candidate for implementing a real-time technique. The introduction of chemical imaging in the routine quality control of pharmaceutical products would profoundly change quality assurance in the pharmaceutical industry.

Study on the Leaching Kinetics of Weathered Crust Elution-Deposited Rare Earth Ores by Hydroxypropyl Methyl Cellulose

In the process of the in situ leaching of weathered crust elution-deposited rare earth ores (WCE-DREOs), there are many problems in the conventional leaching agent, such as a slow leaching rate, low leaching yield and long leaching period. In order to solve the above problems, 2.0 wt% ammonium sulfate was mixed with hydroxypropyl methyl cellulose (HPMC). The effects of the HPMC concentration, temperature, pH and flow rate on the leaching kinetics of rare earth (RE) and aluminum (Al) were investigated. The results showed that when the concentration of HPMC was 0.05 wt%, the leaching equilibrium time of RE and Al was about 60% shorter than that of single ammonium sulfate. With an increase in the leaching temperature, the leaching equilibrium time of RE and Al decreased, and the apparent activation energy of RE and Al was 23.13 kJ/mol and 17.31 kJ/mol, respectively. The leaching process was in line with the internal diffusion kinetic control model. When the pH of the leaching agent was 4.02~8.01, the leaching yield of RE and Al was basically the same, but the leaching yield of Al was greatly increased at pH 2.0 due to a large amount of adsorbed hydroxy-Al in the RE ore eluded. The leaching yield reached the maximum when the flow rate was 0.7 mL/min. The leaching time and the leaching cost of RE can be saved by the composite leaching agent. The results provide theoretical guidance for the development and industrial application of the new composite leaching agent.

Effect of silica fume and PCE-HPMC on LC3 mortar: Microstructure, statistical optimization and life cycle Assessment

With immense carbon emissions, the cement and concrete industries account for nearly eight percent of the world’s total. As the demand for urbanisation increases, the carbon footprint of the industry will also increase rapidly. A sustainable and greener low carbon cement called limestone calcined clay cement (LC3) is being developed as a promising alternative to ordinary Portland cement (OPC). The present study investigates the effects of silica fume (SF) on LC3 with variable dosages of polycarboxylate ether-based superplasticizer (SP) and hydroxypropyl methylcellulose (HPMC) admixtures. Using three level-three factorial (33) Box Behnken Design and response surface methodology (RSM), SF content, SP content, HPMC content, and flow value were set as input parameters to optimise and evaluate the eight output response parameters, namely, water binder (w/b) ratio, compressive strength (7 and 28 days), modulus of rupture, porosity, water absorption, ultrasonic pulse velocity, and water sorptivity. With a combined desirability of 90.8% for an optimised mix, the model showed that with 0% SF, 0.811% SP, 0.923% HPMC, and 124.12 mm of FV, a LC3-50-based cement system with higher physico-mechanical properties can be developed. The microstructural analysis was also conducted through a scanning electron microscope (SEM), Thermogravimetric Analyzer (TGA), and X-ray diffraction (XRD). The results showed Calcium silicate hydrate (C-S-H) development along with consumption of portlandite (CH) for LC3-50-based cement systems. Sustainability analysis of LC3-based mortar in terms of carbon emissions showed a 33.82% reduction in CO2 emissions as compared to OPC.

Mechanisms of swelling inhibition and seepage promotion of weathered crust elution-deposited rare earth ore by hydroxypropyl methyl cellulose

In-situ leaching process of weathered crust elution-deposited rare earth ore (WCE-DREO) often faces problems such as poor permeability and occurrence of landslides. The main reasons are the swelling of clay minerals by water absorption and blockage of seepage channels by fine particles. This study proposed using hydroxypropyl methyl cellulose (HPMC) as a novel green swelling inhibitor with the combination of ammonium sulfate ((NH4)2SO4) as an efficient composite leaching agent. The swelling inhibition performance of HPMC on swelling inhibition was evaluated through linear swelling tests and mud ball immersion tests. The mechanisms of HPMC on swelling inhibition and seepage promotion were analyzed by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Scanning electron microscopy (SEM), Surface area analysis (BET), X-ray photoelectron spectroscopy (XPS), Thermogravimetric analysis (TGA), and the contact angle, zeta potential and particle size distribution were characterized. The results indicated that HPMC showed a good performance on swelling inhibition, which improved with the increase of HPMC concentration. HPMC expels the water from the interlayer. Moreover, HPMC adsorbs onto the surface of clay minerals by hydrogen bonding to form a hydrophobic film, which can prevent the clay minerals from hydration swelling. Due to the electric neutrality property of HPMC, the electrostatic repulsion of clay minerals can be reduced. Therefore, the fine particles of the clay minerals can be bridged to form larger particles by the long carbon chain of HPMC which leads to expansion of the seepage channels as well as the improvement of the permeability of the ores. According to the column leaching tests, the novel leaching agent composed of 0.05 wt% HPMC and 2 wt% (NH4)2SO4 not only showed a good leaching capacity of rare earth, but also inhibited the swelling of clay and enhanced the seepage when comparing with traditional leaching agent ((NH4)2SO4). Developing a novel leaching agent benefits the green, safe and high-efficiency exploitation of WCE-DREO.

Effects of hydroxypropyl methylcellulose on anti-dispersion and rheology of alkali-activated materials in underwater engineering

To explore the feasibility of applying alkali-activated materials (AAM) to underwater engineering. The effects of hydroxypropyl methylcellulose (HPMC) on the anti-dispersion and rheological properties of AAM were investigated. NaOH was selected as the activator, and granulated blast furnace slag (GBFS) and fly ash (FA) were used as precursors. The characteristics of anti-dispersion, rheology, and hydration heat change of alkali-activated slurry with 6 kinds of HPMC content (0, 0.2%, 0.4%, 0.6%, 0.8%, and 1%) and 4 kinds of alkali content (Na2O: 3%, 5%, 7%, and 9%) were discussed. The anti-dispersion was characterized by turbidity. The fluidity, gel time, yield stress and plastic viscosity were obtained from rheological tests. The hydration heat was measured by isothermal calorimetry. The results show that HPMC can improve the anti-dispersion of alkali-activated slurry with alkali content (Na2O: 3%, 5%), and the effect was good when the content exceeded 0.6%. Compared with that without HPMC, the turbidity was reduced by 98.4% at 1% HPMC content. With the increase of HPMC, the fluidity and gel time decreased, and the yield stress and plastic viscosity increased at the initial stage. The fluidity of alkali-activated slurry decreased by 23% and the plastic viscosity increased by 916%. It is due to the thickening effect of HPMC, which can change the anti-dispersion and rheology of slurry. The mechanism of HPMC can increase the attraction between raw material particles, and the molecular chains overlap to form a network structure that can wrap the alkali-activated slurry. The evolution of shear stress and hydration heat show that HPMC can delay the hydration reaction of AAM. When the alkali content is high (Na2O: 7%, 9%), HPMC has no obvious improvement in the anti-dispersion of alkali-activated slurry. The increase of HPMC content has no effect on the yield shear stress and plastic viscosity at the initial stage. It shows that HPMC fails at high Na2O content, which leads to loss of thickening effect. The paper is expected to guide for using HPMC in underwater engineering to improve the anti-dispersion and workability of AAM.

Formation and characterization of oleogels derived from emulsions: Evaluation of polysaccharide ratio and emulsification method

In the present work, highly oil-binding oleogels were fabricated by two polysaccharides (insoluble soybean fiber (ISF) and hydroxypropyl methylcellulose (HPMC)) using an emulsion-templated method. The polysaccharide-based network was developed by oven-drying ISF and HPMC co-stabilized emulsions to obtain the oleogels and two emulsification methods were compared. The aqueous polysaccharide mixtures displayed an increased hydrodynamic diameter but decreased viscosity with increasing proportions of ISF, leading to a reduced interfacial tension. Increased HPMC reduced the droplet size of emulsions while it improved the apparent viscosity and loss modulus. Emulsions prepared by high-pressure homogenization displayed a smaller droplet size and lower viscosity while the oleogels exhibited abundant liquid oil. By contrast, emulsions prepared by high-speed shearing presented a larger droplet size while the oleogels exhibited well-structured semi-solid oil. The oleogels were endowed with stronger gel strength (increased to 184 g and 461 g, respectively) and hardness from increased HPMC, resulting in a decreased oil loss. Increasing the HPMC content contributed to a more compact structure of the oleogels and emulsions whereby emulsions with a too small droplet size were difficult to be fully converted into gel-like semi-solid oil. Results indicate that ISF and HPMC can be applied in structuring oleogels as substitutes for solid fats.

Formulation and evaluation of orally disintegrating film (ODF) containing piperine-succinic acid cocrystal

Piperine is a type of alkaloid found in plants of the Piperaceae family, including Piper nigrum and Piper longum , which has numerous pharmacological properties and is being developed as a nutraceutical. However, its poor solubility makes delivering in effective doses for therapeutic purposes challenging. To overcome this limitation, the cocrystals of piperine and succinic acid was prepared, which are more soluble, and then formulated into orally disintegrating films (ODFs) for better delivery. The cocrystals were formed using the slurry method, while the ODFs were made using the solvent-casting method with different concentrations of hydroxypropyl methylcellulose (HPMC) and polyethylene glycol (PEG) 400. The resulting films were evaluated for various parameters, such as their organoleptic characteristics, weight and thickness uniformity, pH, moisture content, swelling properties, and disintegration time. The results showed that the ODF with 6% HPMC as a film-forming polymer and 0.6% PEG 400 as a plasticizer loaded with 10 mg of piperine in the form of piperine-succinic acid cocrystal was the best formula. This ODF formulation disintegrated in less than one minute and was found to be a good film with uniform content.

Hydroxypropyl Methylcellulose as Hydrogel Matrix and Citric Acid-Locust Bean Gum as Negative Matrix for Controlled Release Tablet.

Purpose: This study aimed at determining the optimum concentration of hydroxypropyl methylcellulose (HPMC) as hydrogel matrix and citric acid-locust bean gum (CA-LBG) as negative matrix for controlled release tablet formulation. In addition, the study was to determine the effect of CA-LBG and HPMC. CA-LBG accelerates the disintegration of tablets into granules so that the HPMC granule matrix swells immediately and controls drug release. The advantage of this method is that the tablets do not produce large HPMC gel lumps without drug (ghost matrix) but form HPMC gel granules, which can be rapidly degraded after all of the drug is released. Methods : The experiment followed the simplex lattice design to obtain the optimum tablet formula with CA-LBG and HPMC concentrations as optimization factors. Tablet production by the wet granulation method and ketoprofen is the model of the active ingredient. The kinetics of ketoprofen release was studied using several models. Results : Based on the coefficients of each polynomial equation that HPMC and CA-LBG increased the value of angle of repose (29.91:27.87), tap index (18.99:18.77), hardness (13.60:13.32), friability (0.41:0.73), and release of ketoprofen (52.48:99.44). Interaction of HPMC and CA-LBG increased the value of angle of repose (3.25), tap index (5.64), and hardness (2.42). Interaction of HPMC and CA-LBG too decreased the friability value (-1.10) and release of ketoprofen (-26.36). The Higuchi, Korsmeyer-Peppas, and Hixson-Crowell model is the kinetics of eight experimental tablet formulas. Conclusions : The optimum concentrations of HPMC and CA-LBG for controlled release tablets are 32.97 and 17.03%, respectively. HPMC, CA-LBG, and a combination of both affect the physical quality of tablet and tablet mass. CA-LBG is a new excipient candidate that can control drug release from tablets by the matrix disintegration mechanism on the tablet.

Fabrication of Gastro-Floating Famotidine Tablets: Hydroxypropyl Methylcellulose-Based Semisolid Extrusion 3D Printing.

Semisolid extrusion (SSE) three-dimensional (3D) printing uses drug-loaded paste for the printing process, which is capable of constructing intricate 3D structures. This research presents a unique method for fabricating gastro-floating tablets (GFT) using SSE. Paste-loaded famotidine with a matrix made of hydroxypropyl methylcellulose (HPMC) were prepared. Nine 3D printed tablets were developed with different HPMC concentrations and infill percentages and evaluated to determine their physicochemical properties, content uniformity, dissolution, and floating duration. The crystallinity of the drug remained unchanged throughout the process. Dissolution profiles demonstrated the correlation between the HPMC concentration/infill percentage and drug release behavior over 10 h. All the fabricated GFTs could float for 10 h and the Korsmeyer-Peppas model described the dissolution kinetics as combination of non-Fickian or anomalous transport mechanisms. The results of this study provided insight into the predictability of SSE 3D printability, which uses hydro-alcoholic gel-API blend materials for GFTs by controlling traditional pharmaceutical excipients and infill percentages. SSE 3D printing could be an effective blueprint for producing controlled-release GFTs, with the additional benefits of simplicity and versatility over conventional methods.

Preparation and investigation of electrical conductivity of silver nanoparticle films on the paper substrate

This paper reported the preparation of silver nanoparticles (Ag NPs) by the chemical protection-reduction method. This process was performed in an aqueous phase with a mixture consisting of silver nitrate (AgNO3), hydroxypropyl methylcellulose (HPMC), sodium borohydride (NaBH4), and hydrazine (H2N-NH2). The prepared Ag NPs were characterized by transmission electron microscope (TEM) and ultraviolet-visible (UV-Vis) spectroscopy. The TEM images indicated that Ag NPs had high purity with the size of 20‒50 nm. The Ag NPs solution strongly absorbed around 420 nm and displayed brown color under visible light. The stability of the Ag NPs solution was maintained after 60 days of storage. The conductivity of the Ag NPs solution depended on the initial concentration of AgNO3, HPMC content, type of reducing agent, pH environment, and also the order of using reducing agents in the prepared process. Next, the Ag NPs solution was coated to form a film on the paper substrate. The thickness of the obtained film was about 49.2 µm according to the analysis results from the Leica 2500 DM microscope and its conductivity was investigated by the four-point probe method. The film could conduct the electricity and light up LEDs when using a 9 V DC power source. The obtained results demonstrated that the prepared Ag NPs would have a potential application as conductive inks in electrical plastic devices.

Pilot-scale binder jet 3D printing of sustained release solid dosage forms

The additive nature and versatility of 3D printing show great promise in the rapid prototyping of solid dosage forms for clinical trials and mass customization for personalized medicine applications. This paper reports the formulation and process development of sustained release solid dosage forms, termed “printlets”, using a pilot-scale binder jetting (BJT) 3D printer and acetaminophen (APAP) as the model drug. With the inclusion of hydroxypropyl methylcellulose (HPMC) as a release retardant polymer in the print powder, the drug release time of APAP increased considerably from minutes to hours. However, given the swelling propensity of HPMC, a thicker layer of powder must be laid down during printing to avoid any shape distortion of the printlets. For a fixed print volume, the level of binder saturation (i.e., ratio between the liquid binder and powder in the as-printed sample) is inversely proportional to the thickness of the spread powder layer. An increase in the spread powder layer inadvertently resulted in a lower level of binder saturation and consequently weaker printlets. By increasing the level of binder saturation with jetting from more print heads, the mechanical strength of printlets containing 18% HPMC was successfully restored. The resultant printlets have a drug release time of 3.5 h and a breaking force of 12.5 kgf that is comparable to the fast-disintegrating printlets containing no HPMC and surpasses manually pressed tablets with the same HPMC content.

Development of Besifloxacin HCL Loaded Ocular İn Situ Gels; In Vitro Characterization Study

Objective: The aim of this study is to develop in situ gel formulations containing besifloxacin hydrochloride are heat triggered, which are prepared by using different poloxomer and derivatives different polymers that will change the gelling temperature to increase corneal contact time, regulate drug release, improve ocular bioavailability and increase patient compliance increase mucoadhesion.&#x0D; Material and Method: Various concentrations of poloxamer 188 (P188) and poloxamer 407 (P407) were used to create the in situ forming gels. To increase the gel's capacity for bioadhesion, mucoadhesives such hydroxypropylmethyl cellulose (HPMC) or hydroxyethyl cellulose (HEC) were included in the formulations. Drug release in vitro, sol-gel transition temperature, rheological behavior, pH, clarity, and mucoadhesion force were all assessed for the produced formulations. &#x0D; Result and Discussion: The developed formulations' gelation temperatures ranged from 29 to 35°C. The preparations' viscosity and mucoadhesion force increased with increasing P407, HPMC, and HEC concentrations. Besifloxacin HCl forms in situ gel formulas with K1, K2, K3, and K6 suited for mucoadhesion characteristics, gelation temperature, and viscosity. These formulations exhibit pseudoplastic flow. Increasing polymer concentrations resulted in a reduction in the burst release of the formulations. However, at the end of 6 hours, drug release was finished in all formulations. The results show that in situ gels containing P407 and P188 show promise for besifloxacin HCl application

Synthesis of antibacterial hydroxypropyl methylcellulose and silver nanoparticle biocomposites via solution plasma using silver electrodes

The biocomposites of hydroxypropyl methylcellulose (HPMC)/silver nanoparticles (AgNPs) were synthesized using the solution plasma process (SPP). HPMC/AgNPs were synthesized in 1–5 % HPMC solutions using silver electrodes. UV–Vis spectroscopy showed a peak near 400 nm and the peak increased as the concentration of HPMC and discharge time increased. FTIR analysis indicated no change in the chemical structure of the HPMC based biocomposites. Spherical shaped AgNPs with size ranges about 2–18 nm and well dispersed in the porous HPMC matrices with fringed edges were observed by TEM and SEM/EDS analyses. The synthesized biocomposites were found to be thermo-stable by TGA analysis. The inhibition zones of bacterial growth formed by the HPMC/AgNPs biocomposites were in the range of 8–14.3 mm; minimal inhibition concentrations, in the range of 10–15 μg·mL−1 for Gram-negative bacteria; 25–30 μg·mL−1 for Gram-positive bacteria. The biocomposites were non-toxic to the HEK293 cells up to 125 μg·mL−1. The results indicated that the synthesis of antibacterial agents in the HPMC matrix using silver electrodes via SPP would be an efficient and safe way for the development of biopolymer based antimicrobials and wound healing biomaterials.

Fabrication and characterization of super-hydrophilic poly (ε-caprolactone)/hydroxypropyl methylcellulose (HPMC) based composite electrospun membranes for tissue engineering applications.

Tissue engineering (TE) employs scaffolds as a structural support for initially seeding of cells followed by development of new tissues. Electrospun scaffolds generally function as a template of native extracellular matrix (ECM). The chemical composition of the scaffold and its surface morphology strongly influence the interaction between various cell types and materials. In this work, PCL and PCL/HPMC-based composite membranes with varying concentrations of HPMC (20-30% by weight) were fabricated using electrospinning technique. The membranes were evaluated for their surface, physio-chemical and biological properties. It was observed probably for the first time that blending of HPMC with PCL produced super-hydrophilic scaffolds. DSC studies confirmed the semi- crystalline nature of HPMC. PCL/HPMC composite scaffolds are found biocompatible from cytotoxicity assay. From the cell culture studies (apoptosis), PCL/HPMC composite scaffolds did not inhibit the adhesion of L929 cells due to their super-hydrophilic nature. The cell adhesion and spreading varied with HPMC concentration. PCL/HPMC (70/30) membranes showed highest cell adhesion among others due to its porous structure.

Green synthesis of well-dissolved high-stable silver nanoparticles using hydroxypropylmethyl cellulose as a protective agent

This paper presented the synthesis of Ag nanoparticles (Ag NPs) by the chemical reduction method which is simple and environmentally friendly. Silver nitrate, hydroxypropylmethyl cellulose (HPMC), and glucose were used as silver precursors, protective agents, and reducing agents, respectively. The effects of AgNO3 concentration, glucose concentration, HPMC content, reaction time, and reaction temperature on the formation of Ag NPs were investigated. The properties of Ag NPs were analyzed by transmission electron microscopy (TEM), ultraviolet-visible (UV-Vis) spectroscopy, and X-ray diffraction (XRD). The results indicated that when the HPMC content was 0.01%, AgNO3 concentration was 0.05 M and glucose reducing agent concentration was 0.4%, the best reaction occurred in 9 hours at 90oC. The Ag NPs prepared under HPMC protection possessed a face-centered cubic crystal structure (FCC), a spherical shape having average sizes in the range of 8 ‒ 12 nm. The Ag colloidal solution had a suitable zeta potential (-37.21 mV) to maintain the stability and to avoid the agglomeration of Ag NPs. In addition,the paper proposed a method to indirectly determine the Ag NPs content through the separation of Ag NPs from the colloidal solution by coagulation, using the electrolyte Al(NO3)3.9H2O.

Evaluation of mechanical and thermal properties of carrageenan/hydroxypropyl methyl cellulose hard capsule

AbstractThe inherent source of gelatin used for commercial hard capsules causes a surging demand for vegetarian capsules. In this work, carrageenan is utilized in preparing hard capsules to meet consumer preferences. Hydroxypropyl methylcellulose (HPMC) was incorporated as a reinforcing agent to improve the low mechanical properties of hard capsules made of carrageenan. The HPMC concentration was manipulated from 0.2 to 1.0 w/v% in the carrageenan matrix. The increasing concentration of HPMC exerts significant effects on the tensile strength and elongation at break, with an improvement of 59.1% and 46.9%, respectively, at the optimized HPMC concentration of 0.8 w/v%. The loop strength of the capsule is also increased by 56.4% with decreasing moisture content. The downfield movement from around 3.20 ppm of the carrageenan proton to 3.33 ppm in the proton nuclear magnetic resonanance ( 1H‐NMR) spectrum suggests the formation of intermolecular hydrogen bonding between carrageenan and HPMC, which correlates to the results of Fourier‐transform infrared spectroscopy (FTIR) and zeta potential. The glass transition temperature of the film was increased from 37.8 to 65.3°C, showing an upgrade in thermal stability. The film possesses a major mass loss with an activation energy of 64.7 kJ/mol with an increment of 43.4% compared to the control carrageenan. These findings support the conclusion that HPMC enhanced the mechanical properties and thermal stability of the carrageenan film, and the comprehensive analysis of the molecular interaction and decomposition kinetics subsequently may expand the application fields of the carrageenan‐HPMC hard capsule as an alternative to gelatin in the future.