Synthesis of Gallic Acid-Loaded Chitosan-Grafted-2-Acrylamido-2-Methylpropane Sulfonic Acid Hydrogels for Oral Controlled Drug Delivery: In Vitro Biodegradation, Antioxidant, and Antibacterial Effects

Gallic acid: a dietary metabolite's therapeutic potential in the management of atherosclerotic cardiovascular disease

Atherosclerotic cardiovascular disease (ASCVD) causes significant morbidity and mortality globally. Most of the chemicals specifically target certain pathways and minimally impact other diseases associated with ASCVD. Moreover, interactions of these drugs can cause toxic reactions. Consequently, the exploration of multi-targeted and safe medications for treating and preventing ASCVD has become an increasingly popular trend. Gallic acid (GA), a natural secondary metabolite found in various fruits, plants, and nuts, has demonstrated potentials in preventing and treating ASCVD, in addition to its known antioxidant and anti-inflammatory effects. It alleviates the entire process of atherosclerosis (AS) by reducing oxidative stress, improving endothelial dysfunction, and inhibiting platelet activation and aggregation. Additionally, GA can treat ASCVD-related diseases, such as coronary heart disease (CHD) and cerebral ischemia. However, the pharmacological actions of GA in the prevention and treatment of ASCVD have not been comprehensively reviewed, which limits its clinical development. This review primarily summarizes the in vitro and in vivo pharmacological actions of GA on the related risk factors of ASCVD, AS, and ASCVD. Additionally, it provides a comprehensive overview of the toxicity, extraction, synthesis, pharmacokinetics, and pharmaceutics of GA,aimed to enhance understanding of its clinical applications and further research and development.

Gallic acid-guar gum and chitosan-based polyelectrolyte complex film exhibited enhanced wound healing in full-thickness excision wound model

Recently, there has been a great interest in the development of innovative wound dressing materials based on natural bioactives, as they can accelerate the healing process and address the issues related to traditional wound dressings. The current study focuses on developing a novel derivative of guar gum (GG) and gallic acid (GA) using a simple, free radical-mediated polymerization reaction aimed at enhancing the antioxidant properties of GG. Multiple spectroscopic investigations were performed to validate the GA-GG conjugate. NMR and FTIR confirmed GA integration, UV spectroscopy indicated changes in electronic transition, DSC analysis suggested a reduction in crystallinity, and XRD revealed structural modifications. SEM revealed a porous structure that reflected its polymerized nature. Due to inadequate mechanical strength and film-forming ability of the synthesized GA-GG conjugate, polyelectrolyte complexation method using chitosan was explored to form a polyelectrolyte complex (PEC) film. The film exhibited a high swelling rate, excellent antioxidant properties, and was both hemocompatible and exhibited improved antimicrobial properties. In vitro, in ovo, and in vivo characterizations were performed to compare the performance of these biocomposite films to those of their counterparts. It promoted angiogenesis in the chick yolk sac membrane and demonstrated good cytocompatibility in cell proliferation studies on the viability of the L929 mouse fibroblast cell line. In vivo wound healing efficacy of the PEC film in wound closure was 94.5% as compared to the untreated disease control group (p < 0.001). This work highlights the development of an innovative GA-GG conjugate/chitosan PEC-based film with significant potential for wound healing applications.

Development of pH-responsive Hydrogel from Copolymers of Artemisia vulgaris Seed Mucilage, Mucin, and poly(methacrylate) for Controlled Delivery of Acyclovir Sodium

To cope with the constraints of conventional drug delivery systems, site-specific drug delivery systems are the major focus of researchers. The present research developed water-swellable, pH-responsive methacrylic acid-based hydrogel scaffolds of Artemisia vulgaris seed mucilage with mucin and loaded with acyclovir sodium as a model drug. The developed hydrogel discs are evaluated for diverse parameters. Drug loading efficiency in all formulations ranges from 63% to 75%. The hydrogels exhibited pH-dependent swelling, displaying optimum swelling in a phosphate buffer (pH 7.4), and insignificant swelling in an acidic buffer (pH 1.2), in addition, they responded well to electrolyte concentrations. The sol-gel fraction is estimated ranging from 60 to 95%. Dissolution studies unveiled sustained drug release for 24 h in a phosphate buffer of pH 7.4, exhibiting zero-order release kinetics. Moreover, FTIR spectra confirmed the drug-excipient compatibility. SEM photomicrographs revealed a rough and porous surface of hydrogel discs with several pores and channels. The PXRD diffractograms exposed the amorphous nature of the polymeric blends. The findings of acute toxicity studies proved the developed hydrogel network is biocompatible. Therefore, these outcomes connote the newly created network as a smart delivery system, able to dispatch acyclovir sodium into the intestinal segment for a prolonged period.

Recent Advancements in Gallic Acid-Based Drug Delivery: Applications, Clinical Trials, and Future Directions

Gallic acid (GA) is a well-known herbal bioactive compound found in many herbs and foods like tea, wine, cashew nuts, hazelnuts, walnuts, plums, grapes, mangoes, blackberries, blueberries, and strawberries. GA has been reported for several pharmacological activities, such as antioxidant, inflammatory, antineoplastic, antimicrobial, etc. Apart from its incredible therapeutic benefits, it has been associated with low permeability and bioavailability issues, limiting their efficacy. GA belongs to BCS (Biopharmaceutics classification system) class III (high solubility and low probability). In this context, novel drug delivery approaches played a vital role in resolving these GA issues. Nanocarrier systems help improve drug moiety's physical and chemical stability by encapsulating them into a lipidic or polymeric matrix or core system. In this regard, researchers have developed a wide range of nanocarrier systems for GA, including liposomes, transfersomes, niosomes, dendrimers, phytosomes, micelles, nanoemulsions, metallic nanoparticles, solid lipid nanoparticles (SLNs), nanoparticles, nanostructured lipid carriers, polymer conjugates, etc. In the present review, different search engines like Scopus, PubMed, ScienceDirect, and Google Scholar have been referred to for acquiring recent information on the theme of the work. Therefore, this review paper aims to emphasize several novel drug delivery systems, patents, and clinical updates of GA.

Fisetin-loaded pluronic-based nanogel: Radiation synthesis for alleviating neurocognitive impairments in a rat model of alzheimer's disease via modulation of the apoptotic cascade

Alzheimer's disease (AD) is a neurodegenerative disorder marked by cognitive impairment and memory loss. In this study, AD was experimentally induced in rats using aluminum chloride (AlCl3) and D-galactose (D-gal). Fisetin (Fis), a natural compound with antioxidant and anti-inflammatory properties, has potential for neurodegeneration management, but its low bioavailability limits clinical applications. To address this, we synthesized and characterized Pluronic-2-Acrylamido-2-methylpropane sulfonic acid (PLUR-PAMPS) nanogels using gamma radiation and successfully loaded Fis onto them (Fis-PLUR-PAMPS). The optimal formulation exhibited minimal particle size, a highly acceptable polydispersity index, and the highest zeta-potential, enhancing stability and solubilization efficiency. Our goal was to improve Fis's bioavailability and assess its efficacy against AlCl3/D-gal-induced AD. Male albino Wistar rats were pre-treated orally with Fis (40 mg/kg) or Fis-PLUR-PAMPS for seven days, followed by a seven-day intraperitoneal injection of AlCl3 and D-gal. Behavioral assessments, histopathological analysis, and biochemical evaluation of markers related to AD pathology were conducted. Results demonstrated that Fis-PLUR-PAMPS effectively mitigated cognitive impairments and neurodegenerative signs induced by AlCl3/D-gal. These findings suggest that Fis-PLUR-PAMPS nanogels enhance Fis's bioavailability and therapeutic efficacy, offering a promising approach for AD management.

Design and Characterization of Chitosan-Based Smart Injectable Hydrogel for Improved Sustained Release of Antinarcotics

The treatment adherence of narcotics-addicted individuals with reduced incidences of relapse can be enhanced by a sustained drug release formulation of antinarcotics. So far, different drug formulations have been reported with sustained drug release periods of 28 and 35 days. To further enhance this duration, different formulations of injectable hydrogels (IHs) have been developed by combining low molecular weight (LMW) and high molecular weight (HMW) chitosan (CS) with guar gum (GG) and crosslinking them by sodium bi phosphate dibasic. The structural, morphological, and physicochemical properties of LMW-CS IH, and HMW-CS IH were evaluated using Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), and rheological, swelling, and biodegradation analysis. The HMW-CS IH showed high crosslinking, increased thermal stability, high mechanical strength, elevated swelling, and low biodegradation. The antinarcotic drugs naltrexone (NTX) and disulfiram (DSF) were loaded separately into the HMW-CS IH and LMW-CS IH. The release of NTX and DSF was investigated in phosphate buffer saline (PBS) and ethanol (0.3%, 0.4%, and 0.5%) over a 56-day period using an UV spectrophotometer. The drug release data were tested in zero-order, first-order, and Korsemeyer-Peppas mathematical models. In PBS, all prepared formulations followed non-Fickian drug release, while in ethanol, only NTX HMW-CS IH followed non-Fickian release in all three different concentrations of ethanol.

Porous antimicrobial crosslinked film of hydroxypropyl methylcellulose/carboxymethyl starch incorporating gallic acid for wound dressing application

Because of weak mechanical qualities and low degree of swelling of hydroxypropyl methylcellulose/carboxymethyl starch (HP/CMS) blended films for wound dressing application, this work prepared a unique antimicrobial crosslinked film utilizing succinic acid (SA) as a non-toxic crosslinker and gallic acid (GAL) as an antibacterial agent. It was observed that the infrared-shifted peak position of OH stretching and bending in HP/CMS/SA/GAL films was caused by hydrogen bond formation among HP, CMS and GAL components. The antimicrobial crosslinked films considerably enhanced their mechanical properties and swelling degree. After adding SA and GAL, the films retained their porosity structure as observed by scanning electron images. Moreover, GAL-loaded HP/CMS/SA films could inhibit Staphylococcus aureus and Escherichia coli growth, showing their wound dressing potential. Crystallinity percentage, water vapor transmission rate, gel fraction, water solubility, water uptake and cytotoxicity were also investigated.

Effects of Phenolics on the Physicochemical and Structural Properties of Collagen Hydrogel

In the current era, the treatment of collagen hydrogels with natural phenolics for the improvement in physicochemical properties has been the subject of considerable attention. The present research aimed to fabricate collagen hydrogels cross-linked with gallic acid (GA) and ellagic acid (EA) at different concentrations depending on the collagen dry weight. The structural, enzymatic, thermal, morphological, and physical properties of the native collagen hydrogels were compared with those of the GA/EA cross-linked hydrogels. XRD and FTIR spectroscopic analyses confirmed the structural stability and reliability of the collagen after treatment with either GA or EA. The cross-linking also significantly contributed to the improvement in the storage modulus, of 435 Pa for 100% GA cross-linked hydrogels. The thermal stability was improved, as the highest residual weight of 43.8% was obtained for the hydrogels cross-linked with 50% GA in comparison with all the other hydrogels. The hydrogels immersed in 30%, 50%, and 100% concentrations of GA also showed improved swelling behavior and porosity, and the highest resistance to type 1 collagenase (76.56%), was obtained for 50% GA cross-linked collagen hydrogels. Moreover, GA 100% and EA 100% obtained the highest denaturation temperatures (Td) of 74.96 °C and 75.78 °C, respectively. In addition, SEM analysis was also carried out to check the surface morphology of the pristine collagen hydrogels and the cross-linked collagen hydrogels. The result showed that the hydrogels cross-linked with GA/EA were denser and more compact. However, the improved physicochemical properties were probably due to the formation of hydrogen bonds between the phenolic hydroxyl groups of GA and EA and the nitrogen atoms of the collagen backbone. The presence of inter- and intramolecular cross-links between collagen and GA or EA components and an increased density of intermolecular bonds suggest potential hydrogen bonding or hydrophobic interactions. Overall, the present study paves the way for further investigations in the field by providing valuable insights into the GA/EA interaction with collagen molecules.

Multifunctional and theranostic hydrogels for wound healing acceleration: An emphasis on diabetic-related chronic wounds

Hydrogels represent intricate three-dimensional polymeric structures, renowned for their compatibility with living systems and their ability to naturally degrade. These networks stand as promising and viable foundations for a range of biomedical uses. The practical feasibility of employing hydrogels in clinical trials has been well-demonstrated. Among the prevalent biomedical uses of hydrogels, a significant application arises in the context of wound healing. This intricate progression involves distinct phases of inflammation, proliferation, and remodeling, often triggered by trauma, skin injuries, and various diseases. Metabolic conditions like diabetes have the potential to give rise to persistent wounds, leading to delayed healing processes. This current review consolidates a collection of experiments focused on the utilization of hydrogels to expedite the recovery of wounds. Hydrogels have the capacity to improve the inflammatory conditions at the wound site, and they achieve this by diminishing levels of reactive oxygen species (ROS), thereby exhibiting antioxidant effects. Hydrogels have the potential to enhance the growth of fibroblasts and keratinocytes at the wound site. They also possess the capability to inhibit both Gram-positive and Gram-negative bacteria, effectively managing wounds infected by drug-resistant bacteria. Hydrogels can trigger angiogenesis and neovascularization processes, while also promoting the M2 polarization of macrophages, which in turn mitigates inflammation at the wound site. Intelligent and versatile hydrogels, encompassing features such as pH sensitivity, reactivity to reactive oxygen species (ROS), and responsiveness to light and temperature, have proven advantageous in expediting wound healing. Furthermore, hydrogels synthesized using environmentally friendly methods, characterized by high levels of biocompatibility and biodegradability, hold the potential for enhancing the wound healing process. Hydrogels can facilitate the controlled discharge of bioactive substances. More recently, there has been progress in the creation of conductive hydrogels, which, when subjected to electrical stimulation, contribute to the enhancement of wound healing. Diabetes mellitus, a metabolic disorder, leads to a slowdown in the wound healing process, often resulting in the formation of persistent wounds. Hydrogels have the capability to expedite the healing of diabetic wounds, facilitating the transition from the inflammatory phase to the proliferative stage. The current review sheds light on the biological functionalities of hydrogels, encompassing their role in modulating diverse mechanisms and cell types, including inflammation, oxidative stress, macrophages, and bacteriology. Additionally, this review emphasizes the significance of smart hydrogels with responsiveness to external stimuli, as well as conductive hydrogels for promoting wound healing. Lastly, the discussion delves into the advancement of environmentally friendly hydrogels with high biocompatibility, aimed at accelerating the wound healing process.

Hydroxyethyl Cellulose-Based Hydrogels as Controlled Release Carriers for Amorphous Solid Dispersion of Bioactive Components of Radix Paeonia Alba

Radix Paeoniae Alba (RPA) has been used extensively in Chinese traditional medicine to treat gastrointestinal disorders, immune-modulating diseases, cancers, and numerous other conditions. A few of its active components include paeoniflorin, albiflorin, lactiflorin, and catechin. However, their therapeutic effectiveness is compromised by poor pharmacokinetic profiles, low oral bioavailability, short half-lives, and poor aqueous solubility. In this study, hydroxyethyl cellulose-grafted-2-acrylamido-2-methylpropane sulfonic acid (HEC-g-AMPS) hydrogels were successfully prepared for the controlled release of Radix Paeonia Alba-solid dispersion (RPA-SD). A total of 43 compounds were identified in RPA-SD using UHPLC-Q-TOF-MS analysis. The hydrogel network formation was confirmed by FTIR, TGA, DSC, XRD, and SEM. Hydrogels' swelling and drug release were slightly higher at pH 1.2 (43.31% swelling, 81.70% drug release) than at pH 7.4 (27.73% swelling, 72.46% drug release) after 48 h. The gel fraction, drug release time and mechanical strength of the hydrogels increased with increased polymer and monomer concentration. Furthermore, the hydrogels were porous (84.15% porosity) and biodegradable (8.9% weight loss per week). Moreover, the synthesized hydrogels exhibited excellent antimicrobial and antioxidative properties.

pH Modulated Formation of Complexes with Various Stoichiometry between Polymer Network and Fe(III) in Thermosensitive Gels Modified with Gallic Acid

Thermoresponsive gels based on N-isopropylacrylamide functionalized with amino groups were modified with gallic acid, with gallate (3,4,5-trihydroxybenzoic) groups being introduced into the polymer network. We investigated how the properties of these gels were affected at varying pH, by the formation of complexes between the polymer network of the gels and Fe³⁺ ions (which form stable complexes with gallic acid, exhibiting 1:1, 1:2, or 1:3 stoichiometry, depending on pH). The formation of complexes with varying stoichiometry within the gel was confirmed using UV-Vis spectroscopy, and the influence of such complexes on swelling behavior and volume phase transition temperature were investigated. In the appropriate temperature range, complex stoichiometry was found to strongly affect the swelling state. Changes in the pore structure and mechanical properties of the gel caused by the formation of complexes with varying stoichiometry were investigated using scanning electron microscopy and rheological measurements, respectively. The volume changes exhibited by p(NIPA-5%APMA)-Gal-Fe gel were found to be greatest at close to human body temperature (~38 °C). Modification of thermoresponsive pNIPA gel with gallic acid opens new opportunities for the development of pH- and thermosensitive gel materials.

Ellagic Acid Inclusion Complex-Loaded Hydrogels as an Efficient Controlled Release System: Design, Fabrication and In Vitro Evaluation

Oxidants play a crucial role in the development of oxidative stress, which is linked to disease progression. Ellagic acid is an effective antioxidant with applications in the treatment and prevention of several diseases, since it neutralizes free radicals and reduces oxidative stress. However, it has limited application due to its poor solubility and oral bioavailability. Since ellagic acid is hydrophobic, it is difficult to load it directly into hydrogels for controlled release applications. Therefore, the purpose of this study was to first prepare inclusion complexes of ellagic acid (EA) with hydroxypropyl-β-cyclodextrin and then load them into carbopol-934-grafted-2-acrylamido-2-methyl-1-propane sulfonic acid (CP-g-AMPS) hydrogels for orally controlled drug delivery. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) were used to validate ellagic acid inclusion complexes and hydrogels. There was slightly higher swelling and drug release at pH 1.2 (42.20% and 92.13%) than at pH 7.4 (31.61% and 77.28%), respectively. Hydrogels had high porosity (88.90%) and biodegradation (9.2% per week in phosphate-buffered saline). Hydrogels were tested for their antioxidant properties in vitro against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). Additionally, the antibacterial activity of hydrogels was demonstrated against Gram-positive bacterial strains (Staphylococcus aureus and Escherichia coli) and Gram-negative bacterial strains (Pseudomonas aeruginosa).

Study of Hydroxypropyl β-Cyclodextrin and Puerarin Inclusion Complexes Encapsulated in Sodium Alginate-Grafted 2-Acrylamido-2-Methyl-1-Propane Sulfonic Acid Hydrogels for Oral Controlled Drug Delivery

Puerarin has been reported to have anti-inflammatory, antioxidant, immunity enhancement, neuroprotective, cardioprotective, antitumor, and antimicrobial effects. However, due to its poor pharmacokinetic profile (low oral bioavailability, rapid systemic clearance, and short half-life) and physicochemical properties (e.g., low aqueous solubility and poor stability) its therapeutic efficacy is limited. The hydrophobic nature of puerarin makes it difficult to load into hydrogels. Hence, hydroxypropyl-β-cyclodextrin (HP-βCD)-puerarin inclusion complexes (PIC) were first prepared to enhance solubility and stability; then, they were incorporated into sodium alginate-grafted 2-acrylamido-2-methyl-1-propane sulfonic acid (SA-g-AMPS) hydrogels for controlled drug release in order to increase bioavailability. The puerarin inclusion complexes and hydrogels were evaluated via FTIR, TGA, SEM, XRD, and DSC. Swelling ratio and drug release were both highest at pH 1.2 (36.38% swelling ratio and 86.17% drug release) versus pH 7.4 (27.50% swelling ratio and 73.25% drug release) after 48 h. The hydrogels exhibited high porosity (85%) and biodegradability (10% in 1 week in phosphate buffer saline). In addition, the in vitro antioxidative activity (DPPH (71%), ABTS (75%), and antibacterial activity (Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa) indicated the puerarin inclusion complex-loaded hydrogels had antioxidative and antibacterial capabilities. This study provides a basis for the successful encapsulation of hydrophobic drugs inside hydrogels for controlled drug release and other purposes.

Synthesis and Evaluation of Rutin–Hydroxypropyl β-Cyclodextrin Inclusion Complexes Embedded in Xanthan Gum-Based (HPMC-g-AMPS) Hydrogels for Oral Controlled Drug Delivery

Oxidants play a significant role in causing oxidative stress in the body, which contributes to the development of diseases. Rutin—a powerful antioxidant—may be useful in the prevention and treatment of various diseases by scavenging oxidants and reducing oxidative stress. However, low solubility and oral bioavailability have restricted its use. Due to the hydrophobic nature of rutin, it cannot be easily loaded inside hydrogels. Therefore, first rutin inclusion complexes (RIC) with hydroxypropyl-β-cyclodextrin (HP-βCD) were prepared to improve its solubility, followed by incorporation into xanthan gum-based (hydroxypropyl methylcellulose-grafted-2-acrylamido -2-methyl-1-propane sulfonic acid) hydrogels for controlled drug release in order to improve the bioavailability. Rutin inclusion complexes and hydrogels were validated by FTIR, XRD, SEM, TGA, and DSC. The highest swelling ratio and drug release occurred at pH 1.2 (28% swelling ratio and 70% drug release) versus pH 7.4 (22% swelling ratio, 65% drug release) after 48 h. Hydrogels showed high porosity (94%) and biodegradation (9% in 1 week in phosphate buffer saline). Moreover, in vitro antioxidative and antibacterial studies (Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli) confirmed the antioxidative and antibacterial potential of the developed hydrogels.