Acrylic Acid Content Research Articles

Acrylic Acid Modified Poly-ethylene Glycol Microparticles for Affinity-Based release of Insulin-Like Growth Factor-1 in Neural Applications.

Sustained release of bioactive molecules via affinity-based interactions presents a promising approach for controlled delivery of growth factors. Insulin-like growth factor-1 (IGF-1) has gained increased attention due to its ability to promote axonal growth in the central nervous system. In this work, we aimed to evaluate the effect of IGF-1 delivery from polyethylene-glycol diacrylate (PEG-DA) microparticles using affinity-based sustained release on neurons. We developed PEG-DA-based microparticles with varying levels of acrylic acid (AA) as a comonomer to tune their overall charge. The particles were synthesized via precipitation polymerization under UV light, yielding microparticles (MPs) with a relatively low polydispersity index. IGF-1 was incubated with the PEG-DA particles overnight, and formulations with a higher AA content resulted in higher loading efficiency and slower release rates over 4 weeks, suggesting the presence of binding interactions between the positively charged IGF-1 and negatively charged particles containing AA. The released IGF-1 was tested in dorsal root ganglion (DRG) neurite outgrowth assay and found to retain its biological activity for up to two weeks after encapsulation. Furthermore, the trophic effect of IGF-1 was tested with stem cell-derived V2a interneurons and found to have a synergistic effect when combined with neurotrophin-3 (NT3). To assess the potential of a combinatorial approach, IGF-1-releasing MPs were encapsulated within a hyaluronic acid (HA) hydrogel and showed promise as a dual delivery system. Overall, the PEG-DA MPs developed herein deliver bioactive IGF-1 for a period of weeks and hold potential to enable axonal growth of injured neurons via sustained release.

Preparation of high-performance water-based ink from acrylic-modified rosin resin

This study focuses on the preparation of a water-based ink binder using acrylic-modified rosin polyethylene glycol ester (ROPEGE). This binder is characterized by a low acid value (12.23 mg NaOH/g), low viscosity (5.40 mPa s), high fixed content (92.40 %), and excellent printability. Compared to reported water-based inks, the inks derived in this study exhibit higher fixed content (resulting in lower VOC emissions), low acid value (indicating high oxidation resistance), and low viscosity (enhancing print quality). The individual effects of emulsifier type, emulsifier content, initiator type, initiator content, acrylic acid content, and dispersant content are analyzed as single factors. The optimal formulation is achieved by selecting specific components: emulsifier PEG-400 (40 wt%/ROPEGE), initiator potassium persulfate (10 wt%/ROPEGE), functional monomer acrylic acid (10 wt% of ROPEGE), and wetting and dispersing agent OT-75 (10 wt%/ROPEGE). The enhancement of the water-based ink formulation is accomplished through the use of acrylic-modified rosin resin (AMRR) as the binder, dimethyl silicone oil as the defoamer, and malachite green as the pigment.

Thermo-mechanical properties of shape-recoverable structural composites via vacuum-assisted resin transfer molding process and in-situ polymerization of poly (tert-butyl acrylate-co-acrylic acid) copolymer

When selecting a polymer matrix to make shape memory polymer composites (SMPCs), it is crucial to consider high elastic modulus below the switching temperature (Tsw), a significant variation in the modulus above Tsw, and the ability to control Tsw. This research introduces shape-recoverable structural composites fabricated from poly (tert-butyl acrylate-co-acrylic acid) (PtBA-AA), which has a significant modulus variation before and after Tsw. Capillary numbers are assessed to minimize void formation at varying acrylic acid (AA) concentrations, which regulate the copolymer’s polarity and the thermo-mechanical properties. The glass transition temperature of PtBA-AA can be adjusted from 47.4 °C to 91.6 °C. Furthermore, the elastic modulus of SMPC increases from 13 GPa to 20 GPa, whereas the tensile strength increases from 526 MPa to 889 MPa. The maximum recovery strength measured 100.4 MPa at an AA molar ratio of 0.23, accompanied by a fixity of 89.1 % and a recovery ratio of 97.2 %.

Hard- and Soft-Coded Strain Stiffening in Metamaterials via Out-of-Plane Buckling Using Highly Entangled Active Hydrogel Elements.

Metamaterials show elaborate mechanical behavior such as strain stiffening, which stems from their unit cell design. However, the stiffening response is typically programmed in the design step and cannot be adapted postmanufacturing. Here, we show hydrogel metamaterials with highly programmable strain-stiffening responses by exploiting the out-of-plane buckling of integrated pH-switchable hydrogel actuators. The stiffening upon reaching a certain extension stems from the initially buckled active hydrogel beams. At low strain, the beams do not contribute to the mechanical response under tension until they straighten with a resulting step-function increase in stiffness. In the hydrogel actuator design, the acrylic acid concentration hard-codes the configuration of the metamaterial and range of possible stiffening onsets, while the pH soft-codes the exact stiffening onset point after fabrication. The utilization of out-of-plane buckling to realize subsequent stiffening without the need to deform the passive structure extends the application of hydrogel actuators in mechanical metamaterials. Our concept of out-of-plane buckled active elements that stiffen only under tension enables strain-stiffening metamaterials with high programmability before and after fabrication.

PH-Sensitive Hydrogels Fabricated with Hyaluronic Acid as a Polymer for Site-Specific Delivery of Mesalamine.

Hydrogels with the main objective of releasing mesalamine (5-aminosalicylic acid) in the colon in a modified manner were formulated in the present work using a free-radical polymerization approach. Different ratios of hyaluronic acid were cross-linked with methacrylic and acrylic acids using methylenebis(acrylamide). The development of a new polymeric network and the successful loading of drug were revealed by Fourier transform infrared spectroscopy. Thermogravimetric analysis demonstrated that the hydrogel was more thermally stable than the pure polymer and drug. Scanning electron microscopy (SEM) revealed a rough and hard surface which was relatively suitable for efficient loading of drug and significant penetration of dissolution medium inside the polymeric system. Studies on swelling and drug release were conducted at 37 °C in acidic and basic conditions (pH 1.2, 4.5, 6.8, and 7.4, respectively). Significant swelling and drug release occurred at pH 7.4. Swelling, drug loading, drug release, and gel fraction of the hydrogels increased with increasing hyaluronic acid, methacrylic acid, and acrylic acid concentrations, while the sol fraction decreased. Results obtained from the toxicity study proved the formulated system to be safe for biological systems. The pH-sensitive hydrogels have the potential to be beneficial for colon targeting due to their pH sensitivity and biodegradability. Inflammatory bowel disease may respond better to hydrogel treatment as compared to conventional dosage forms. Specific amount of drug is released from hydrogels at specific intervals to maintain its therapeutic concentration at the required level.

A superabsorbent and pH-responsive copolymer-hydrogel based on acemannan from Aloe vera (Aloe barbadensis M.): A smart material for drug delivery

Combining natural polysaccharides with synthetic materials improves their functional properties which are essential for designing sustained-release drug delivery systems. In this context, the Aloe vera leaf mucilage/hydrogel (ALH) was reacted with acrylic acid (AA) to synthesize a copolymerized hydrogel, i.e., ALH-grafted-Polyacrylic acid (ALH-g-PAA) through free radical copolymerization. Concentrations of the crosslinker N,N′-methylene-bis-acrylamide (MBA), and the initiator potassium persulfate (KPS) were optimized to study their effects on ALH-g-PAA swelling. The FTIR and solid-state NMR (CP/MAS 13C NMR) spectra witnessed the formation of ALH-g-PAA. Scanning electron microscopy (SEM) analysis revealed superporous nature of ALH-g-PAA. The gel fraction (%) of ALH-g-PAA was directly related to the concentrations of AA and MBA whereas the sol fraction was inversely related to the concentrations of AA and MBA. The porosity (%) of ALH-g-PAA directly depends on the concentration of AA and MBA. The ALH-g-PAA swelled admirably at pH 7.4 and insignificantly at pH 1.2. The ALH-g-PAA offered on/off switching properties at pH 7.4/1.2. The metoprolol tartrate was loaded on different formulations of ALH-g-PAA. The ALH-g-PAA showed pH, time, and swelling-dependent release of metoprolol tartrate (MT) for 24 h following the first-order kinetic and Korsmeyer-Peppas model. Haemocompatibility studies ascertained the non-thrombogenic and non-hemolytic behavior of ALH-g-PAA.

Investigation of structure, morphology, and corrosion behavior of carboxylic acids/hydroxyapatite/chitosan coatings on Ti discs for implants

Titanium (Ti) and its alloys are widely used in bone defect repair owing to their advantages, including high strength, corrosion resistance, and biocompatibility. The formation of a stable oxide layer on Ti implants enhances the osseointegration process. Nevertheless, additional progress is required to improve the incorporation of these implants at the microscopic and nanoscopic levels to achieve a biocompatible interface. The main objective of this study was to enhance the morphology of hydroxyapatite and the corrosion resistance of Ti implants by applying hydroxyapatite/chitosan (HA/Cs) nanocomposite coatings embedded with carboxylic acids. The coatings were fabricated by electrodeposition, wherein various acid concentrations (acrylic and acetic acids) were employed as Cs electrolyte solvents to enhance the adhesion and bond strength with the titanium metal substrate. The microstructures of the HA/Cs coatings were analyzed using X-ray diffraction. The results demonstrated that the structure of HA was affected by the type of acid used and its concentration as the crystallinity increased with a high concentration of acrylic acid. Additionally, the morphology of HA/Cs was analyzed using a transmission electron microscope. The results showed that the morphology of HA/Cs changed from a hexagonal rod-like shape with acrylic acid samples into a needle-like shape in acetic acid samples. The corrosion behavior was investigated using electrochemical impedance spectroscopy (EIS) in a simulated body fluid (SBF) at 37±2ºC. The EIS results showed a high corrosion resistance with phase angles close to −80° and high impedance values of 80.5 kΩ cm2 with a high concentration of acrylic acid. These results indicated the formation of a highly adhesive and stable film on the implants in the test solution. In conclusion, based on this study and our previous work, the corrosion resistance, good biocompatibility, and biomineralization properties of the prepared HA/Cs-coated Ti recommend it as an alternative implant for clinical applications.

Dielectric elastomers with large actuation strain and high output force

AbstractDielectric elastomer actuator (DEA) is considered as an ideal artificial muscle with soft and light in nature, widespread application in soft robotics and sensors. Dielectric elastomer (DE), the core component of DEA, with high output force and large actuation strain under relatively low driving electric field is critical for high‐performance DEA. However, the widely used VHB series (3M) DE suffered from very large pre‐strain and high driving voltage to get their high actuation performance, limiting their scope of application. In this work, the DEs with good mechanical and dielectric properties were prepared via UV curing method consisting of acrylic acid (AA) with strong polar groups as functional monomer, n‐butyl acrylate (BA) as soft monomer and urethane acrylate as cross‐linker (c‐p(BA‐AA)). The c‐p(BA‐AA) DE films obtained the simultaneous increasing of dielectric constant and breakdown strength with the increasing content of AA, which guaranteed the good actuation performance. The c‐p(BA‐AA) film exhibited excellent actuating performance (44.11% actuation strain at 45 kV/mm) without pre‐strain. Besides, a simple linear actuator based on the c‐p(BA‐AA) film could easily output weight that is tens of times of its own active weight (654.1 mN/g at 30 kV/mm).

Innovative sodium acrylate wastewater resource recovery through electrodialysis with integrated bipolar membranes

With the process of industrialization, many production fields produce high-salt organic wastewater. In this work, we have employed an electrodialysis (ED)-resin-bipolar membrane electrodialysis (BMED) mixed process to address sodium acrylate wastewater, achieving resource recovery. The influences of the initial volume ratio and applied voltage were investigated. In the ED-resin, the separation of organic compounds and pigments such as sodium acrylate and phenol was realized. The desalting rate could reach 93.1%, the energy consumption is 0.6 kWh/kg C3H3O2Na, and the chroma removal rate can reach 99%. In the subsequent BMED phase, we attain notable acrylic acid and base concentrations, reaching levels of 1.59 mol/L and 3.12 mol/L, with a current efficiency of 58.14% and an energy consumption of 3.28 kWh/kg NaOH. In addition, economic and environmental evaluations verify the feasibility of this process, which is indicative of its prospect of industrial application.

Effect of acrylic acid on water‐whitening resistance of polyacrylate latex films and its mechanism

AbstractTwo groups of polyacrylate latexes with higher (21 ~ 35 °C) or lower (−33 ~ −43 °C) glass transition temperatures (Tg) were prepared by adjusting the monomer ratio of butyl acrylate (BA) and styrene (St), and the effect of acrylic acid (AA) on water‐whitening resistance of these latex films was investigated. It was found that the water‐whitening resistance of the two groups of latex films was different. With the increase of AA content, the water whitening resistance of the latex films with higher Tg continued to improve, while that of the latex films with lower Tg increased first and then decreased. A series of characterizations, such as light transmittance, water whitening, water absorption, static water contact angle, surface morphology, and optical microscope test of the latex film, and so forth, showed that the reason for this difference was that under higher AA content (≥5%), compared with the polyacrylate latex films with lower Tg, the latex films with higher Tg could reach the saturation state of water absorption quickly, and water in these latex films exhibited continuous and large area distribution, rather than formation of many so‐called micro‐ or nano‐scale water sacs that can scatter light as found in the latex films with lower Tg.

Anisotropically self-oscillating gels by spatially patterned interpenetrating polymer network.

Here we introduce sub-millimeter self-oscillating gels that undergo the Belousov-Zhabotinsky (BZ) reaction and can anisotropically oscillate like cardiomyocytes. The anisotropically self-oscillating gels in this study were realized by spatially patterning an acrylic acid-based interpenetrating network (AA-IPN). We found that the patterned AA-IPN regions, locally introduced at both ends of the gels through UV photolithography, can constrain the horizontal gel shape deformation during the BZ reaction. In other words, the two AA-IPN regions could act as a physical barrier to prevent isotropic deformation. Furthermore, we controlled the anisotropic deformation behavior during the BZ reaction by varying the concentration of acrylic acid used in the patterning process of the AA-IPN. As a result, a specific directional deformation behavior (66% horizontal/vertical amplitude ratio) was fulfilled, similar to that of cardiomyocytes. Our study can provide a promising insight to fabricating robust gel systems for cardiomyocyte modeling or designing novel autonomous microscale soft actuators.

Environmentally friendly radiation EDTA modified hydrogel based on gelatin for adsorptive removal of cationic and anionic dye from synthetic wastewater

Colored wastewater discharge from several industries, including paper, cosmetics, leather, dying, and textile industries, is a significant environmental management issue, especially in developing countries. Copolymerization of acrylic acid (AAc) as well as gelatin (Gltn) was performed in different compositions and crosslinked utilizing gamma irradiation to form Gltn/AAc hydrogel. EDTA has modified the hydrogel to improve adsorption properties. The effect of irradiation dose, the composition of Gltn-AAc, EDTA content, and AAc content on gel percentage was studied. The swelling behavior were studied as a time function. The prepared hydrogels’ surface morphologies and structure were confirmed with FTIR, SEM, as well as XRD. Modified hydrogel used in batch adsorption was studied to remove anionic and cationic dyes, namely methyl orange (MO) and methylene blue (MB), from simulated wastewater. The parameters of adsorption, like pH, time, and initial metals concentration, were studied. The removal of MB dye by modified Gltn/AAc/EDTA hydrogel was found to be greater than that of MO dye.

Selective Adsorption of Ionic Species Using Macroporous Monodispersed Polyethylene Glycol Diacrylate/Acrylic Acid Microgels with Tunable Negative Charge.

Monodispersed polyethylene glycol diacrylate (PEGDA)/acrylic acid (AA) microgels with a tuneable negative charge and macroporous internal structure have been produced using a Lego-inspired droplet microfluidic device. The surface charge of microgels was controlled by changing the content of AA in the monomer mixture from zero (for noncharged PEGDA beads) to 4 wt%. The macroporosity of the polymer matrix was introduced by adding 20 wt% of 600-MW polyethylene glycol (PEG) as a porogen material into the monomer mixture. The porogen was successfully leached out with acetone after UV-crosslinking, which resulted in micron-sized cylindrical pores with crater-like morphology, uniformly arranged on the microgel surface. Negatively charged PEGDA/AA beads showed improved adsorption capacity towards positively charged organic dyes (methylene blue and rhodamine B) compared to neutral PEGDA beads and high repulsion of negatively charged dye molecules (methyl orange and congo red). Macroporous microgels showed better adsorption properties than nonporous beads, with a maximum adsorption capacity towards methylene blue of 45 mg/g for macroporous PEGDA/AA microgels at pH 8.6, as compared to 23 mg/g for nonporous PEGDA/AA microgels at the same pH. More than 98% of Cu(II) ions were removed from 50 ppm solution at pH 6.7 using 2.7 mg/mL of macroporous PEGDA/AA microgel. The adsorption of cationic species was significantly improved when pH was increased from 3 to 9 due to a higher degree of ionization of AA monomeric units in the polymer network. The synthesized copolymer beads can be used in drug delivery to achieve improved loading capacity of positively charged therapeutic agents and in tissue engineering, where a negative charge of scaffolds coupled with porous structure can help to achieve improved permeability of high-molecular-weight metabolites and nutrients, and anti-fouling activity against negatively charged species.

Synthesis and application of super absorbent polymers synthesized with ammonia solution and diatomaceous earth with low toxic residues

Water-soluble harmful components that remained in SAPs pose potential risks to crop growth, resulting in decreased seed germination rate, reduced yield, and inhibited root system growth. These factors restrict its widespread use in agriculture and forestry. In this study, a new type of super absorbent polymers (AD-SAP) with low residual acrylic acid and sodium ions was synthesized by using ammonia solution instead of strong alkali sodium hydroxide for neutralization and adding modified diatomaceous earth to improve the grafting efficiency. The prepared samples were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS), and the influence of the dosage of acrylic acid and ammonia solution used for preparation on the residual content of water-soluble harmful components in AD-SAPs was investigated. When 28% of acrylic acid, 24% of ammonia solution, and 5% of diatomaceous earth were used for synthesis, the residual acrylic acid content in AD-SAP was 0.03%, and the sodium ion content was reduced to 0.12 g/kg, which is much lower than the three commercially available SAPs. However, its water-absorption capacity has not decreased and its salt resistance has improved. The water absorption ratio of AD-SAP is 578g/g, and the salt-absorption ratio is 87 g/g. Pot experiments showed that AD-SAP eliminated the adverse effects of commercial SAPs on crop growth. The research provided technical support for the production of SAPs, and offer scientific guidance for how to mitigate the adverse effects of SAPs on crop growth.

Cydonia oblonga-Seed-Mucilage-Based pH-Sensitive Graft Copolymer for Controlled Drug Delivery-In Vitro and In Vivo Evaluation.

The primary objective of this study was to assess the potential utility of quince seed mucilage as an excipient within a graft copolymer for the development of an oral-controlled drug delivery system. The Cydonia oblonga-mucilage-based graft copolymer was synthesized via a free radical polymerization method, employing potassium per sulfate (KPS) as the initiator and N, N-methylene bisacrylamide (MBA) as the crosslinker. Various concentrations of monomers, namely acrylic acid (AA) and methacrylic acid (MAA), were used in the graft copolymerization process. Metoprolol tartarate was then incorporated into this graft copolymer matrix, and the resultant drug delivery system was subjected to comprehensive characterization using techniques such as Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The swelling behavior of the drug delivery system was evaluated under different pH conditions, and in vitro drug release studies were conducted. Furthermore, pharmacokinetic parameters including the area under the curve (AUC), maximum plasma concentration (Cmax), time to reach Cmax (Tmax), and half-life (t1/2) were determined for metoprolol-loaded hydrogel formulations in rabbit plasma, and these results were compared with those obtained from a commercially available product. The key findings from the study include observations that higher concentrations of acrylic acid (AA) and Cydonia oblonga mucilage (CM) in the graft copolymer enhanced swelling, while the opposite trend was noted at elevated concentrations of methacrylic acid (MAA) and N, N-methylene bisacrylamide (MBA). FTIR analysis confirmed the formation of the graft copolymer and established the compatibility between the drug and the polymer. SEM imaging revealed a porous structure in the prepared formulations. Additionally, the swelling behavior and drug release profiles indicated a pH-sensitive pattern. The pharmacokinetic assessment revealed sustained release patterns of metoprolol from the hydrogel network system. Notably, the drug-loaded formulation exhibited a higher Cmax (156.48 ng/mL) compared to the marketed metoprolol product (96 ng/mL), and the AUC of the hydrogel-loaded metoprolol was 2.3 times greater than that of the marketed formulation. In conclusion, this study underscores the potential of quince seed mucilage as an intelligent material for graft-copolymer-based oral-controlled release drug delivery systems.

Enhancement of adhesion strength and in-vivo evaluation of electrodeposited calcium phosphate/chitosan biocoatings on titanium substrate

Chitosan/calcium phosphate nanocomposites are widely used as a biocompatible coatings for titanium bioimplants in the fields of dentistry and orthopedics to enhance the integration between the implants and the hard bone. However, the poor adhesion strength between the coating and the metal substrate was found to be one of the major problems in the clinical application of these implants. In the current study, we reported the formation of Ca/P coating on titanium (Ti) substrate using electrodeposition. The key factor of the bath ingredients is the change of chitosan's solvent from a commonly used acetic acid to acrylic acid in the electrolyte. The structural analysis including X-ray diffraction (XRD), Raman spectroscopy, and attenuated total reflectance (ATR) confirmed the formation of three phases of Ca/P octacalcium phosphate (OCP), dicalcium phosphate dihydrate (DCPD) brushite, and hydroxyapatite (HA). The bond strength was performed by the tape test (ASTM D3359-09) which showed that nearly 65% of the coatings were removed in the case of using 2, 4, and 6% (v/v) acetic acid as chitosan solvent, while only 5% of the coatings were removed when high concentrations (4 and 6%) of acrylic acid is used in addition to increasing of the surface wettability. Furthermore, the morphology and thickness of the calcium phosphate layer coated on the surface of Ti metal were inspected by scanning electron microscopy (SEM). Finally, an in vivo application was conducted on the optimized coating by surgically placing the coated and control discs into rats’ clavicular bones for 2-weeks healing period. Then biomechanical evaluation was performed to verify the effect of treatment on the interface resistance to shear force, and histological analysis was performed to evaluate the bone tissue reactions to coated discs. The results showed that using acrylic acid instead of acetic acid to dissolve chitosan before in-situ electrodeposition might be an innovative approach to enhance the adhesion strength between chitosan/calcium phosphate-based coatings and titanium metal to be used in orthopedic and dental implant technology.

Optimising reaction variables for the preparation of superabsorbent iron fertiliser hydrogel using sugarcane bagasse: A sustainable approach to improve crop nutrient release

Iron (Fe) is a vital micronutrient essential for crop growth and development. Utilisation of bio-based, environmentally friendly functional polymers is inevitable for society. As an alternative to the conventional Fe fertiliser, the present study aimed to synthesise a higher Fe percentage containing hydrogel with organic substances that can facilitate the slow release of nutrients, reduce fertiliser nutrient fixation, and minimise environmental pollution. The reaction variables were optimised for the preparation of superabsorbent using sugarcane bagasse and nano-zeolite-based slow-release Fe fertiliser (SR Fe) hydrogel. This was formulated by graft, co-polymerising acrylic acid, acrylamide, sugarcane bagasse, and nano-zeolite with N,N'-methylene bis-acrylamide as a crosslinker and ammonium persulfate as an initiator. Based on the swelling percentage, the reaction variables of the SR Fe fertiliser were standardised. The crosslinker (MBA - 10 wt%), the initiator (APS - 10 wt%), the filler (Nano-zeolite - 10 wt%), the monomer acrylamide composition (AAm - 2g), the acrylic acid content (AA - 7 ml), the reaction temperature (60oC), and the drying temperature (40oC) were chosen based on desirable swelling percentage and loaded with Fe fertiliser. The Fe fertiliser was loaded to sugarcane bagasse in different ratios (1:0.5, 1:1, 1:1.5, 1:2). The present study showed that the SR Fe fertiliser with the highest percentage of Fe (6.4%) in the ratio of sugarcane bagasse to Fe fertiliser of 1:2 could be used as an effective SR Fe fertiliser to supply nutrients slowly to crops to meet their nutrient needs and improve nutrient use efficiency.

Fabrication and In vitro Evaluation of Carbopol/Polyvinyl Alcohol-based pH-sensitive Hydrogels for Controlled Drug Delivery.

Diclofenac sodium has a short half-life (about 1.5 hours), requiring repeated administration, and as a result, serious complications, such as GI bleeding, peptic ulcer, and kidney and liver dysfunction, are generated. Hence, a sustained/controlled drug delivery system is needed to overcome the complications caused by the administration of diclofenac sodium. This study aimed to fabricate and evaluate carbopol/polyvinyl alcohol-based pH-sensitive hydrogels for controlled drug delivery. pH-sensitive carbopol/polyvinyl alcohol graft-poly(acrylic acid) hydrogels (Cp/PVA-g-PAa hydrogels) were developed for the controlled delivery of diclofenac sodium. The combination of carbopol/polyvinyl alcohol, acrylic acid, and ethylene glycol dimethacrylate was used as polymer, monomer, and cross-linker, respectively. The effects of the formulation's composition on porosity, swelling index, and release pattern of diclofenac sodium from the developed hydrogels were investigated. An increase in porosity and swelling was observed with the increasing amounts of carbopol and acrylic acid, whereas polyvinyl alcohol showed the opposite effect. Due to the formation of a highly viscous system, the drug release decreased with the increasing concentrations of carbopol and polyvinyl alcohol while increased with increasing acrylic acid concentration. The pH-responsive properties of the fabricated hydrogels were demonstrated by dynamic swelling and drug release studies at three different pH values. Higher dynamic swelling and diclofenac sodium (model drug) release were found at high pH values compared to low pH values, i.e., pH 7.4 > 4.6 > 1.2, respectively. Cytotoxicity studies reported no toxic effect of the prepared hydrogels, thus indicating that the prepared hydrogels are safe to be used on clinical basis. The prepared carbopol/polyvinyl alcohol crosslinked hydrogel can be used as a promising carrier for the controlled release of drugs.

The Aptness of Organic Diluents with Tri‐n‐Butyl Phosphate for Liquid‐Liquid Equilibria of Acrylic Acid

AbstractSeparation of carboxylic acids from downstream is a bottleneck in the chemical industry since it takes nearly 30–50 % of the overall production cost. In view of this, an attempt was made for the extraction of acrylic acid from aqueous solution with tri‐n‐butyl phosphate dissolved in organic diluents like benzene, toluene, xylene, hexane, and petroleum ether. The results are explained in terms of distribution coefficient (σ), extraction efficacy (η%), equilibrium complexation constant (Kε), loading ratio (ϕ), and coextraction of water. At lower concentration of acrylic acid and higher concentration of tri‐n‐butyl phosphate for the acrylic acid‐tri‐n‐butyl phosphate system, maximum extraction efficacy and distribution coefficient for benzene was found as 88.60 % and 7.772, respectively. Coextraction of water in the extract phase and law of mass action were discussed, too. Diffusivity of acrylic acid to the interface of extract (organic) and raffinate (aqueous) phases was calculated using the Wilke‐Chang equation and Reddy‐Doraiswamy equation. In view of designing a continuous extraction column, the number of theoretical stages and minimum solvent‐to‐feed ratio were also determined.

Xanthan-Gum/Pluronic-F-127-Based-Drug-Loaded Polymeric Hydrogels Synthesized by Free Radical Polymerization Technique for Management of Attention-Deficit/Hyperactivity Disorder.

Smart and intelligent xanthan gum/pluronic F-127 hydrogels were fabricated for the controlled delivery of atomoxetine HCl. Different parameters such as DSC, TGA, FTIR, XRD, SEM, drug loading, porosity, swelling index, drug release, and kinetics modeling were appraised for the prepared matrices of hydrogels. FTIR confirmed the successful synthesis of the hydrogel, while TGA and DSC analysis indicated that the thermal stability of the reagents was improved after the polymerization technique. SEM revealed the hard surface of the hydrogel, while XRD indicated a reduction in crystallinity of the reagents. High gel fraction was achieved with high incorporated contents of the polymers and the monomer. An increase in porosity, drug loading, swelling, and drug release was observed with the increase in the concentrations of xanthan gum and acrylic acid, whereas Pluronic F-127 showed the opposite effect. A negligible swelling index was shown at pH 1.2 and 4.6 while greater swelling was observed at pH 7.4, indicating a pH-responsive nature of the designed hydrogels. Furthermore, a higher drug release was found at pH 7.4 compared to pH 1.2 and 4.6, respectively. The first kinetics order was followed by the prepared hydrogel formulations. Thus, it is signified from the discussion that smart xanthan gum/pluronic F-127 hydrogels have the potential to control the release of the atomoxetine HCl in the colon for an extended period of time.