Hydroxypropyl Methylcellulose Hydrogel Research Articles

Dexamethasone nanocrystals-embedded hydroxypropyl methylcellulose hydrogel increases cochlear delivery and attenuates hearing loss following intratympanic injection

Herein, dexamethasone (DEX) nanocrystalline suspension (NS)-embedded hydrogel (NS-G) was constructed using a hydroxypropyl methylcellulose (HPMC) polymer to enhance cochlear delivery and attenuate hearing loss following intratympanic (IT) injection. Hydrophobic steroidal nanocrystals were prepared using a bead milling technique and incorporated into a polysaccharide hydrogel. The NS-G system with HPMC (average molecular weight, 86,000 g/mol; 15 mg/mL) was characterized as follows: rod-shaped drug crystalline; particle size <300 nm; and constant complex viscosity ≤1.17 Pa·s. Pulverization of the drug particles into submicron diameters enhanced drug dissolution, while the HPMC matrix increased the residence time in the middle ear cavity, exhibiting a controlled release profile. The IT NS-G system elicited markedly enhanced and prolonged drug delivery (> 9 h) to the cochlear tissue compared with that of DEX sodium phosphate (DEX-SP), a water-soluble prodrug. In mice with kanamycin- and furosemide-induced ototoxicity, NS-G markedly enhanced hearing preservation across all frequencies (8–32 kHz), as revealed by an auditory brainstem response test, compared with both saline and DEX-SP. Moreover, treatment with NS-G showed enhanced anti-inflammatory effects, as evidenced by decreased levels of inflammation-related cytokines. Therefore, the IT administration of DEX NS-loaded HPMC hydrogels is a promising strategy for treating hearing loss.

Rheological and osteogenic effect of Agaricus blazei Murill polysaccharides on composite hydrogels based on HPMC/graphene oxide – A preliminary study

This study aimed to prepare and preliminarily characterize the potential bone restorative effect of composite hydrogels based on hydroxypropylmethylcellulose (HPMC), graphene oxide (GO), and polysaccharides from Agaricus blazei Murill mushroom (PAb). The chemical composition and morphology of the biomaterials were analyzed using FTIR, XRD, SEM, and EDS. Rheological tests were conducted on the hydrogels to assess their flow properties for in vivo application and product stability. Cytotoxicity assays were performed using the GO (1 – 100 µg mL–1) against human neutrophils. Additionally, an in vivo tooth extraction test was carried out by applying HPMC hydrogels containing GO and PAb directly into the alveoli to enhance oral bone restoration. The rheological behavior of the hydrogels followed the Ostwald de Waele model (R² > 0.99), with flow index (n) values below 1.0, indicating a pseudoplastic behavior. Furthermore, the consistency index (k) values increased with the addition of GO and PAb, suggesting a more complex structure, and altered flow behavior at lower shear rates. In the MTT assay, GO exhibited low cytotoxicity towards human neutrophils, maintaining cell viability above 95.0 % even at high concentrations. For the in vivo study, a bisphosphonate-induced osteonecrosis model was used to assess bone tissue healing through macroscopic and radiographic analyses. A significant improvement was observed in the reduction of bone tissue loss in rats treated with the hydrogels compared to the negative control (ZA group). These findings indicate that composite hydrogels containing HMPC/GO/PAb have the potential to be used as biomaterials for mitigating bone loss.

Tailoring of Bilosomal Nanogel for Augmenting the Off-Label Use of Sildenafil Citrate in Pediatric Pulmonary Hypertension.

Pediatric pulmonary hypertension is a serious syndrome with significant morbidity and mortality. Sildenafil is widely used off-label in pediatric patients with pulmonary arterial hypertension. In this study, bile salt-stabilized nanovesicles (bilosomes) were screened for their efficacy to enhance the transdermal delivery of the phosphodiesterase type 5 inhibitor, sildenafil citrate, in an attempt to augment its therapeutic efficacy in pediatric pulmonary hypertension. A response surface methodology was implemented for fabricating and optimizing a bilosomal formulation of sildenafil (SDF-BS). The optimized SDF-BS formulation was characterized in terms of its entrapment efficiency (EE), zeta potential, vesicle size, and in vitro release profile. The optimized formula was then loaded onto hydroxypropyl methyl cellulose (HPMC) hydrogel and assessed for skin permeation, in vivo pharmacokinetics, and pharmacodynamic studies. The optimized SDF-BS showed the following characteristic features; EE of 88.7 ± 1.1%, vesicle size of 185.0 + 9.2 nm, zeta potential of -20.4 ± 1.1 mV, and efficiently sustained SDF release for 12 h. Skin permeation study revealed a remarkable improvement in SDF penetration from bilosomal gel compared to plain SDF gel. In addition, pharmacokinetic results revealed that encapsulating SDF within bilosomal vesicles significantly enhanced its systemic bioavailability (∼3 folds), compared to SDF oral suspension. In addition, pharmacodynamic investigation revealed that, compared to plain SDF gel or oral drug suspension, SDF-BS gel applied topically triggered a significant elevation (p < 0.05) in cGMP serum levels, underscoring the superior therapeutic efficacy of SDF-BS gel. Conclusively, bilosomes can be viewed as a promising nanocarrier for transdermal delivery of SDF that would grant higher therapeutic efficiency while alleviating the limitations encountered with SDF oral administration.

Development of mucoadhesive methacrylic anhydride-modified hydroxypropyl methylcellulose hydrogels for topical ocular drug delivery

Oxidative stress is a key factor involved in the development and progression of glaucoma. Curcumin is a natural phenolic compound with antioxidant and ant-inflammatory properties. Due to the ocular physiological and anatomical barriers, conventional eye drops with low ocular bioavailability and high dosing frequency remain challenges in ophthalmic drug delivery. Hydroxypropyl methylcellulose (HPMC) is a hydrophilic polymer and has been widely used as an ocular lubricant. In the study, methacrylated HPMC (HPMC-MA) hydrogels were developed for curcumin delivery. The synthesis processes of HPMC-MA were characterized by Fourier transform infrared spectrophotometer and nuclear magnetic resonance spectrometer. The results of rheological analysis revealed that methacrylation of HPMC could increase the bioadhesive force and exhibit the shear-thinning and self-recovery behaviors. Optimal concentration of curcumin and in-vitro biocompatibility of HPMC-MA were evaluated by cell viability of corneal epithelial cells. The optimized HPMC-MA containing 20 μM of curcumin (HMC) with sustained drug release properties could decrease the oxidative damage in trabecular meshwork cells via decrease of the inflammation and apoptosis. In-vivo biocompatibility of topical administration of HMC was demonstrated in rabbits. The results suggested that HMC with sustained drug release and mucoadhesive properties might has potential in the treatment of glaucoma.

Statement of Retraction: Synthesis of Chemically Cross-Linked Hydroxypropyl Methyl Cellulose Hydrogels and their Application in Controlled Release of 5-Amino Salicylic Acid

Statement of Retraction: Synthesis of Chemically Cross-Linked Hydroxypropyl Methyl Cellulose Hydrogels and their Application in Controlled Release of 5-Amino Salicylic Acid

Development of polymeric IPN hydrogels by free radical polymerization technique for extended release of letrozole: Characterization and toxicity evaluation

Abstract This research study’s objective was to formulate interpenetrating pH-sensitive polymeric networks interpenetrating networks (IPNs) based on hydroxypropylmethylcellulose (HPMC)/Primojel for use in the treatment of various malignant conditions. For controlled release, letrozole (LTZ) was selected as a model drug in HPMC and Primojel-based IPN hydrogels. HPMC and Primojel based IPN hydrogels were fabricated through the free radical polymerization method by utilizing HPMC and Primojel as polymers, methacrylic acid as monomer, ammonium persulfate as initiator, and methylenebisacrylamide as cross-linker. For structural characterization, various techniques such as Fourier transform infrared spectroscopy, Scanning electron microscopy (SEM), DSC, TGA, and Powder x-ray diffraction (PXRD) were applied to IPN samples. In vitro and swelling studies were also employed to observe the response of these polymeric networks against 1.2 and 7.4 pH. TGA and DSC of an optimized loaded formulation possess better thermal stability as compared to individual drug. PXRD depicted minor crystallinity and a significant amorphous nature. SEM images show that polymeric networks possess an uneven and porous surface. Significant swelling and enhanced in-vitro outcomes at a high pH of 7.4 confirmed the IPN pH responsive properties. Toxicological studies performed on rabbits revealed no harm in the results. Thus, IPN based on HPMC/Primojel was successfully synthesized and can be used for LTZ’s controlled release.

Hydroxypropyl Methylcellulose Bioadhesive Hydrogels for Topical Application and Sustained Drug Release: The Effect of Polyvinylpyrrolidone on the Physicomechanical Properties of Hydrogel.

Hydrogels are homogeneous three-dimensional polymeric networks capable of holding large amounts of water and are widely used in topical formulations. Herein, the physicomechanical, rheological, bioadhesive, and drug-release properties of hydrogels containing hydroxypropyl methylcellulose (HPMC) and polyvinylpyrrolidone (PVP) were examined, and the intermolecular interactions between the polymers were explored. A three-level factorial design was used to form HPMC-PVP binary hydrogels. The physicomechanical properties of the binary hydrogels alongside the homopolymeric HPMC hydrogels were characterized using a texture analyzer. Rheological properties of the gels were studied using a cone and plate rheometer. The bioadhesiveness of selected binary hydrogels was tested on porcine skin. Hydrophilic benzophenone-4 was loaded into both homopolymeric and binary gels, and drug-release profiles were investigated over 24 h at 33 °C. Fourier transform infrared spectroscopy (FTIR) was used to understand the inter-molecular drug-gel interactions. Factorial design analysis supported the dominant role of the HPMC in determining the gel properties, rather than the PVP, with the effect of both polymer concentrations being non-linear. The addition of PVP to the HPMC gels improved adhesiveness without significantly affecting other properties such as hardness, shear-thinning feature, and viscosity, thereby improving bioadhesiveness for sustained skin retention without negatively impacting cosmetic acceptability or ease of use. The release of benzophenone-4 in the HPMC hydrogels followed zero-order kinetics, with benzophenone-4 release being significantly retarded by the presence of PVP, likely due to intermolecular interactions between the drug and the PVP polymer, as confirmed by the FTIR. The HPMC-PVP binary hydrogels demonstrate strong bioadhesiveness resulting from the addition of PVP with desirable shear-thinning properties that allow the formulation to have extended skin-retention times. The developed HPMC-PVP binary hydrogel is a promising sustained-release platform for topical drug delivery.

Arthroscopic repair of full-thickness cartilage defects in horses with autologous nasal chondrocytes seeded in an injectable hydrogel: from preclinical development to clinical cases

This study aimed at evaluating the ability of autologous equine nasal chondrocytes (EqNCs) embedded in a silanised hydroxypropyl methylcellulose (Si-HPMC) hydrogel to repair cartilage defects in horses. Autologous EqNCs from the nasal septum were cultured in vitro and mixed with Si-HPMC. This hybrid construct was injected arthroscopically to experimental full-thickness critical-sized cartilage defects in a pilot horse. After this preliminary test, it was implanted in 6 experimental horses and compared with microfracture (positive control) and with debridement only (negative control) using experimental defects created bilaterally on radial carpal bones and medial femoral condyles. Cartilage tissue repair was subsequently investigated arthroscopically, macroscopically and histologically 18 months after the surgical procedure. Two client-owned horses presenting with cartilage damage were also treated using hybrid EqNCs/Si-HPMC constructs. We developed an injection technique for a 3D hybrid construct of EqNC and Si-HPMC under gas arthroscopy. The in situ reticulation and adhesion properties of the construct ensured its stability after injection. The hybrid construct was well tolerated and Si-HPMC was estimated as a safe scaffold for horses. We found a better cartilage healing with our hybrid construct compared to microfracture or defect left empty characterized by an increased type II collagen content in the defects filled with the hybrid construct. In the 2 clinical cases, hybrid construct injection led to the formation of repair tissue exhibiting the gross appearance of articular cartilage and both returned to intended use. This study revealed that EqNCs/Si-HPMC constructs can support the formation of a healing tissue with hyaline cartilage features.

Rheological and mechanical properties of hydroxypropyl methylcellulose-based hydrogels and cryogels controlled by AOT and SDS micelles

HypothesisThe type and concentration of surfactants affect the rheological behavior of hydroxypropyl methylcellulose (HPMC) chains in hydrogels, influencing the microstructure and mechanical properties of HPMC cryogels. ExperimentsHydrogels and cryogels containing HPMC, AOT (bis (2-ethylhexyl) sodium sulfosuccinate or dioctyl sulfosuccinate salt sodium, two C8 chains and sulfosuccinate head group), SDS (sodium dodecyl sulfate, one C12 chain and sulfate head group), and sodium sulfate (salt, no hydrophobic chain) at different concentrations were investigated using small-angle X-ray scattering (SAXS), scanning electron microscopy (SEM), rheological measurements, and compressive tests. FindingsSDS micelles bound to the HPMC chains building “bead necklaces”, increasing considerably the storage modulus G’ values of the hydrogels and the compressive modulus E values of the corresponding cryogels. The dangling SDS micelles promoted multiple junction points among the HPMC chains. AOT micelles and HPMC chains did not form “bead necklaces”. Although AOT increased the G’ values of the hydrogels, the resulting cryogels were softer than pure HPMC cryogels. The AOT micelles are probably embedded between HPMC chains. The AOT short double chains rendered softness and low friction to the cryogel cell walls. Therefore, this work demonstrated that the structure of the surfactant tail can tune the rheological behavior of HPMC hydrogels and hence the microstructure of the resulting cryogels.

Formulation and Evaluation of Diazepam as a Rectal Preparation

Diazepam has become a commonly used drug for treatment of acute repetitive epileptic seizures and febrile convulsions in children. Considering the advantages of rectal administration of diazepam, the objective of this study was to formulate and evaluate rectal hydrogels containing diazepam as a drug substance in combination with suitable co - solvents and preservatives.Prepared HPMC (hydroxypropyl methylcellulose) hydrogels containing different concentrations of diazepam (2, 4 and 6 mg I ml) manifested good quality in respect to physicochemical parameters (pH value, drug content, ingredients content and viscosity), antimicrobial efficiency and microbiological quality. Under the proposed HPLC conditions, satisfactory separation of diazepam and the preservatives used was achieved. In vitro release studies have shown that the total amount ofdiazepam was released in a period of 3 hours. Prepared formulations were stable for four months at 26 C (ambient temperature characteristic of the second climate zone

Thermo-Responsive Poly(N-isopropylacrylamide)/Hydroxypropylmethyl Cellulose Hydrogel with High Luminous Transmittance and Solar Modulation for Smart Windows.

Thermochromic smart windows are considered to be promising energy-saving devices for reducing energy consumption in buildings. The ideal materials for thermochromic smart windows should have high transmittance, high solar modulation, low phase-transition temperature, and excellent high-temperature thermal stability, which are difficult to achieve simultaneously. This work reports a simple one-step low-temperature polymerization method to prepare a thermo-responsive poly(N-isopropylacrylamide)/hydroxypropylmethyl cellulose (PNIPAM/HPMC) hydrogel achieving the above performances simultaneously. The low-temperature polymerization environment endowed the hydrogel with a high luminous transmittance (Tlum) of 90.82%. HPMC as a functional material effectively enhanced the mechanical properties and thermal stability of the hydrogel. Meanwhile, the PNIPAM/HPMC hydrogel showed a low phase-transition temperature (∼32 °C) and high solar modulation (ΔTsol = 81.52%), which proved that it is an ideal material for thermochromic smart windows. Moreover, a PNIPAM/HPMC smart window exhibited high light transmittance (T380-760 = 86.27%), excellent light modulation (ΔT365 = 74.27%, ΔT380-760 = 86.17%, and ΔT940 = 63.93%), good indoor temperature regulation ability and stability, which indicated that it was an attractive candidate for application in reducing energy consumption in buildings. This work also provides an option and direction for modifying PNIPAM-based thermochromic smart windows.

Novel bigels constructed from oleogels and hydrogels with contrary thermal characteristics: Phase inversion and 3D printing applications

In this study, bigels systems with semi-solid properties were prepared by using the mixture of beeswax oleogels and hydroxypropyl methylcellulose (HPMC) hydrogels in different proportions. The observation by confocal laser scanning microscopy (CLSM) showed that bigels with varying oleogel contents presented different types of O/W (20%, 40%, and 50%), semi-bicontinuous (55%), and W/O bigels (60% and 80%), respectively. FTIR results indicated that the spectra of different types of bigels exhibited significant variations between 3600 and 3300 cm −1 (O–H stretching) and 1250-1000 cm −1 (characteristic absorption peaks of HPMC) ranges, which could be used for further determination of the type of bigels. Rheological experimental results showed that W/O bigels and O/W bigels exhibited diametrically opposed thermal properties. In terms of 3D printing capability, W/O bigels with 60% oleogel content exhibited the best printing integrity, while semi-bicontinuous bigels showed the worst extrusion capability due to the inhomogeneity of the system. By printing under different models, it was found that W/O bigels seemed to be more suitable for flat stacked models, while O/W bigels had better performance in models with small-area monolayer structures. These results guided the development of bigels systems that could be applied for food 3D printing. • The variation of oleogel/hydrogel content in bigels led to the phase inversion. • FTIR spectra can be used for further determination of the type of bigels. • W/O bigels and O/W bigels exhibited diametrically opposed thermal properties. • O/W bigels were more suitable for printing small-area monolayer structure models. • The extrusion process of printing had less destructive effect on O/W bigels.

Enhancing the Antifungal Activity and Ophthalmic Transport of Fluconazole from PEGylated Polycaprolactone Loaded Nanoparticles

Fungal eye infections are caused mainly by an eye injury and can result in serious eye damage. Fluconazole (FLZ), a broad-spectrum antifungal agent, is a poorly soluble drug with a risk of hepatotoxicity. This work aimed to investigate the antifungal activity, ocular irritation, and transport of FLZ-loaded poly (ε-caprolactone) nanoparticles using a rabbit eye model. Three formulation factors affecting the nanoparticle's size, zeta potential, and entrapment efficiency were optimized utilizing the Box-Behnken design. Morphological characteristics and antifungal activity of the optimized nanoparticles were studied. The optimized nanoparticles were loaded into thermosensitive in situ hydrogel and hydroxypropylmethylcellulose (HPMC) hydrogel ophthalmic formulations. The rheological behavior, in vitro release and in vivo corneal transport were investigated. Results revealed that the percentage of poly (ε-caprolactone) in the nanoparticle matrix, polymer addition rate, and mixing speed significantly affected the particle size, zeta potential, and entrapment efficiency. The optimized nanoparticles were spherical in shape and show an average size of 145 nm, a zeta potential of -28.23 mV, and a FLZ entrapment efficiency of 98.2%. The antifungal activity of FLZ-loaded nanoparticles was significantly higher than the pure drug. The developed ophthalmic formulations exhibited a pseudoplastic flow, prolonged the drug release and were found to be non-irritating to the cornea. The prepared FLZ pegylated nanoparticles were able to reach the posterior eye segment without eye irritation. As a result, the developed thermosensitive in situ hydrogel formulation loaded with FLZ polymeric nanoparticles is a promising drug delivery strategy for treating deep fungal eye infections.

Pharmaceutical Development of Nanostructured Vesicular Hydrogel Formulations of Rifampicin for Wound Healing.

Chronic wounds exhibit elevated levels of inflammatory cytokines, resulting in the release of proteolytic enzymes which delay wound-healing processes. In recent years, rifampicin has gained significant attention in the treatment of chronic wounds due to an interesting combination of antibacterial and anti-inflammatory effects. Unfortunately, rifampicin is sensitive to hydrolysis and oxidation. As a result, no topical drug product for wound-healing applications has been approved. To address this medical need two nanostructured hydrogel formulations of rifampicin were developed. The liposomal vesicles were embedded into hydroxypropyl methylcellulose (HPMC) gel or a combination of hyaluronic acid and marine collagen. To protect rifampicin from degradation in aqueous environments, a freeze-drying method was developed. Before freeze-drying, two well-defined hydrogel preparations were obtained. After freeze-drying, the visual appearance, chemical stability, residual moisture content, and redispersion time of both preparations were within acceptable limits. However, the morphological characterization revealed an increase in the vesicle size for collagen-hyaluronic acid hydrogel. This was confirmed by subsequent release studies. Interactions of marine collagen with phosphatidylcholine were held responsible for this effect. The HPMC hydrogel formulation remained stable over 6 months of storage. Moving forward, this product fulfills all criteria to be evaluated in preclinical and clinical studies.

Novel color stability and colorimetry-enhanced intelligent CO2 indicators by metal complexation of anthocyanins for monitoring chicken freshness

This study aims to improve the color stability of anthocyanins and develop a CO2-sensitive indicator based on black goji anthocyanin (BGA) extract. Although the BGA extracts showed distinct color changes, such as red–purple–blue, their intrinsic color diminished after 24 h. A metal complexation method was used for the high color stability of BGA. BGA extracts were chelated with various concentrations of Al3+ [0 – 20% (w/w)]. It showed high color stability and strong intensity in a dose-dependent manner. A CO2-sensitive indicator sachet was developed using hydroxypropyl methylcellulose hydrogel, based on 5% (w/w) Al3+-BGA complexes. The indicator was applied to the chicken breast and detected its spoilage after 3 days with its changing color to greyish blue, due to the microbial growth to 7.00 log CFU/g. These results demonstrated the possibility of chelated anthocyanin complexes as indicating dyes and the ability to monitor the food quality changes through noticeable color changes.

DEVELOPMENT OF BIGELS CONTAINING ANTIFUNGAL AGENT FOR VAGINAL INFECTION

Objective: Bigels are unique semi-solid preparations that have piqued the focus of numerous scientists owing to their significant advantages over ordinary gels. The purpose of this study was to develop and characterize innovative Bigels for applications in drug delivery by combining Hydroxypropyl methylcellulose hydrogel and sorbitan monostearate, oils like coconut and olive-based organogel. The existence of both aqueous and oil phases as bigel was revealed by microscopy. Methods: Hydrogels and organogels were prepared separately, and bigels were formed by combining hydrogel and organogel in a predetermined ratio. They were then analyzed employing various physicochemical tests i. e in vitro drug release, microscopy, and other techniques. Microscopy, viscosity measurement, mechanical analysis, and differential scanning calorimetry were used to examine the bigel's microstructures and physicochemical properties. Results: Tube inversion tests reveal that the bigel doesn’t flow under its own weight till 167 min. The microscopy suggested that the gels exhibited fiber-like structures due to the trapping of the organogel inside hydrogel molecules; this entrapment was demonstrated to be uniformly accomplished, resulting in formulation stability, and the DSC study reveals that the terbinafine is not decomposed also after formulating in bigel, and the terbinafine bigel was also found to be stable. The drug-loaded gels demonstrated effective antibacterial activity against Candida species. The formulated bigel shows initial release in 2 h and slowly release later in 4 h. The formed bigel is found to be stable after 3 mo with a pH range of 7.07±0.04, showing good spreadability and drug content was 99.99±0.75. Conclusion: Terbinafine, the drug of preference for the treatment of bacterial vaginosis, demonstrated diffusion-mediated drug release when placed into bigels. In general, the produced bigels might be employed as delivery vehicles for drugs delivered vaginally.

Modularized bioceramic scaffold/hydrogel membrane hierarchical architecture beneficial for periodontal tissue regeneration in dogs

BackgroundDestruction of alveolar bone and periodontal ligament due to periodontal disease often requires surgical treatment to reconstruct the biological construction and functions of periodontium. Despite significant advances in dental implants in the past two decades, it remains a major challenge to adapt bone grafts and barrier membrane in surgery due to the complicated anatomy of tooth and defect contours. Herein, we developed a novel biphasic hierarchical architecture with modularized functions and shape based on alveolar bone anatomy to achieve the ideal outcomes.MethodsThe integrated hierarchical architecture comprising of nonstoichiometric wollastonite (nCSi) scaffolds and gelatin methacrylate/silanized hydroxypropyl methylcellulose (GelMA/Si-HPMC) hydrogel membrane was fabricated by digital light processing (DLP) and photo-crosslinked hydrogel injection technique respectively. The rheological parameters, mechanical properties and degradation rates of composite hydrogels were investigated. L-929 cells were cultured on the hydrogel samples to evaluate biocompatibility and cell barrier effect. Cell scratch assay, alkaline phosphatase (ALP) staining, and alizarin red (AR) staining were used to reveal the migration and osteogenic ability of hydrogel membrane based on mouse mandible-derived osteoblasts (MOBs). Subsequently, a critical-size one-wall periodontal defect model in dogs was prepared to evaluate the periodontal tissue reconstruction potential of the biphasic hierarchical architecture.ResultsThe personalized hydrogel membrane integrating tightly with the nCSi scaffolds exhibited favorable cell viability and osteogenic ability in vitro, while the scratch assay showed that osteoblast migration was drastically correlated with Si-HPMC content in the composite hydrogel. The equivalent composite hydrogel has proven good physiochemical properties, and its membrane exhibited potent occlusive effect in vivo; meanwhile, the hierarchical architectures exerted a strong periodontal regeneration capability in the periodontal intrabony defect models of dogs. Histological examination showed effective bone and periodontal ligament regeneration in the biomimetic architecture system; however, soft tissue invasion was observed in the control group.ConclusionsOur results suggested that such modularized hierarchical architectures have excellent potential as a next-generation oral implants, and this precisely tuned guided tissue regeneration route offer an opportunity for improving periodontal damage reconstruction and reducing operation sensitivity.Graphical

Preparation and Evaluation of Hydrogel Film Containing Tramadol for Reduction of Peripheral Neuropathic Pain

To develop and assess new dosage forms for the alternative to existing oral medication for peripheral neuropathy, a hydrogel film in the skin patch formation containing tramadol hydrochloride (TRA), a water-soluble drug used as an analgesic, was prepared and evaluated. A hydrogel film composed of 20%(w/w) hydroxypropyl methylcellulose (HPMC) irradiated with electron beams had high transparency and elasticity similar to commercially available wound dressings and soft tissues, suggesting that it is a suitable substrate for TRA. The inclusion of TRA was enabled by immersing the HPMC hydrogel film in TRA aqueous solution. The release and skin permeation of TRA from TRA-containing hydrogel films differed depending on the electron beam dose. Moreover, the analgesic effects in mice were confirmed in a dose-dependent manner. This study demonstrated the usefulness of a hydrogel film containing TRA as a new dosage form alternative to the existing oral medication for peripheral neuropathy.

Thermo-rheological properties of chitosan hydrogels with hydroxypropyl methylcellulose and methylcellulose

Thermal and rheological properties of methylcellulose (MC) and hydroxypropyl methylcellulose (HPMC) hydrogels with chitosan (CHI) were investigated to verify the potential application of these blends as structured systems for oil transport (emulgel, oleogels, and bigels). FTIR confirmed hydrophobic interactions of cellulosic polymers with chitosan. In the temperature sweep, the thermosensitive hydrogels showed their reduced gel point compared to the original polymers. The gelation temperature was reduced from 66.9 °C for pure HPMC to 43.6 °C and 43.6 °C (MC pure polymer) to 39.3 °C when 30% CHI was added for both cases. The addition of 20 and 30% chitosan is enough to modify the extension of the gelation temperature of these polymers. These results indicate that the addition of chitosan enables MC and HPMC to form gels at lower temperatures, which could allow milder thermal conditions to be applied in processing oil carrier systems.

HPMC Hydrogel Formation Mechanisms Unveiled by the Evaluation of the Activation Energy.

Aqueous solutions of hydroxypropyl methylcellulose (HPMC) show inverse thermoreversible gelation, i.e., they respond to small temperature variations exhibiting sol–gel transition during heating, and reversibly gel–sol transition during cooling. According to the pertinent literature on HPMC aqueous systems, at room temperature, the loss modulus (G”) is higher than the storage modulus (G’). During the heating ramp, the viscoelastic response follows a peculiar path: initially, G” and G’ smoothly decrease, then drop to a minimum and finally increase. Eventually, G’ overcomes G”, indicating the gel formation. A recent explanation of this behaviour considers a two-step mechanism: first, phase separation occurs, then fibrils form from a polymer-rich phase and entangle, leading to a three-dimensional network. Based on this, our research focuses on the rheological analysis of the different steps of the sol–gel transition of an HPMC aqueous solution. We perform different viscoelastic tests: thermal ramps, time sweeps, and frequency sweeps at selected characteristic temperatures. We couple classical analysis of the SAOS experiments with an innovative approach based on the evaluation of the activation energy (Ea), made possible by the instrument intrinsic temperature oscillations around the target value. Results show that Ea can be a valid tool that contributes to further clarifying the peculiar microstructural evolution occurring in this kind of thermoreversible gel.