pH-responsive CAP-co-poly(methacrylic acid)-based hydrogel as an efficient platform for controlled gastrointestinal delivery: fabrication, characterization, in vitro and in vivo toxicity evaluation

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.

26SCS-Loaded SilMA/Col Composite Sponge with Well-Arranged Layers Promotes Angiogenesis-Based Diabetic Wound Repair by Mediating Macrophage Inflammatory Response

Diabetic wound healing is a significant clinical challenge because abnormal immune cells in the wound cause chronic inflammation and impair tissue regeneration. Therefore, regulating the behavior and function of macrophages may be conducive to improving treatment outcomes in diabetic wounds. Herein, sulfated chitosan (26SCS)-containing composite sponges (26SCS-SilMA/Col-330) with well-arranged layers and high porosity were constructed based on collagen and silk fibroin, aiming to induce an appropriate inflammatory response and promote angiogenesis. The results indicated that the ordered topological structure of composite sponges could trigger the pro-inflammatory response of Mφs in the early stage, and rapid release of 26SCS in the early and middle stages (within the concentration range of 1-3 mg/mL) induced a positive inflammatory response; initiated the pro-inflammatory reaction of Mφs within 3 days; shifted M1 Mφs to the M2 phenotype within 3-7 days; and significantly up-regulated the expression of two typical angiogenic growth factors, namely VEGF and PDGF-BB, on day 7, leading to rapid HUVEC migration and angiogenesis. In vivo data also demonstrated that on the 14th day after surgery, the 26SCS-SilMA/Col-330-implanted areas exhibited less inflammation, faster re-epithelialization, more abundant collagen deposition and a greater number of blood vessels in the skin tissue. The composite sponges with higher 26SCS contents (the (5.0) 26SCS-SilMA/Col-330 and the (7.5) 26SCS-SilMA/Col-330) could better orchestrate the phenotype and function of Mφs and facilitate wound healing. These findings highlight that the 26SCS-SilMA/Col-330 sponges developed in this work might have great potential as a novel dressing for the treatment of diabetic wounds.

Fabrication and characterization of tamarind seed gum based novel hydrogel for the targeted delivery of omeprazole magnesium

The tamarind seed gum based novel hydrogel was fabricated by varying concentration of polymer, monomer and crosslinker for the targeted delivery of omeprazole magnesium at stomach pH of 1.5. The free radical graft copolymerization of 2-acrylamido-2-methyl propane sulfonic acid with tamarind seed gum backbone resulted in hydrogel. The formation of sulfonic acid pendant groups in hydrogel was observed by the existence of an infrared absorption band at 1152 cm-1 for SO group. The conversion to semicrystalline nature on incorporation of drug evidenced by powder X-ray diffraction studies with peaks at 2θ = 20.4° 31.5° and 52.2°. The scanning electron microscopy images showed bigger voids which narrowed down for drug loaded matrix, supported by the presence of a peak for magnesium in the energy dispersive X-ray spectroscopy. The greatest swelling was observed at pH 7 with second-order rate constant 1.5371 (g/g)/min and drug release was found to be 97.85 ± 1 % over 1200 min at pH 1.5. The drug release transport was found combination of diffusion and erosion of polymer chain to be super case II diffusion and Hill equation model was good fit. The hydrogel drug conjugate found to be non-toxic at tested concentrations (17 mg/50 mg) on in-vivo testing in Drosophila model.

Recent advances in cellulose, pectin, carrageenan and alginate-based oral drug delivery systems

Polymers-based drug delivery systems constitute one of the highly explored thrust areas in the field of the medicinal and pharmaceutical industries. In the past years, the properties of polymers have been modified in context to their solubility, release kinetics, targeted action site, absorption, and therapeutic efficacy. Despite the availability of diverse synthetic polymers for the bioavailability enhancement of drugs, the use of natural polymers is still highly recommended due to their easy availability, accessibility, and non-toxicity. The aim of the review is to provide the available literature of the last five years on oral drug delivery systems based on four natural polymers i.e., cellulose, pectin, carrageenan, and alginate in a concise and tabulated manner. In this review, most of the information is in tabulated form to provide easy accessibility to the reader. The data related to active pharmaceutical ingredients and supported components in different formulations of the mentioned polymers have been made available.

Formulation of pH-responsive highly swellable hydrogel scaffolds for controlled release of tramadol HCl: characterization and biocompatibility evaluation

Introduction: The objective of current project was to formulate a system for controlled delivery of Tramadol HCl (TRD), an opioid analgesic used in the treatment of moderate to severe pain. Methods: For this purpose, a pH responsive AvT-co-poly hydrogel network was formulated through free radical polymerization by incorporating natural polymers i.e., aloe vera gel and tamarind gum, monomer and crosslinker. Formulated hydrogels were loaded with Tramadol HCl (TRD) and evaluated for percent drug loading, sol-gel fraction, dynamic and equilibrium swelling, morphological characteristics, structural features and in-vitro release of Tramadol HCl. Results and Discussions: Hydrogels were proved to be pH sensitive as remarkable dynamic swelling response ranging within 2.94g/g-10.81g/g was noticed at pH 7.4 as compared to pH 1.2. Percent drug loading was in the range of 70.28%-90.64% for all formulations. Thermal stability and compatibility of hydrogel components were validated by DSC analysis and FTIR spectroscopy. Controlled release pattern of Tramadol HCl from the polymeric network was confirmed as maximum release of 92.22% was observed for over a period of 24 hours at pH 7.4. Moreover, oral toxicity studies were also conducted in rabbits to investigate the safety of hydrogels. No evidence of any toxicity, lesions and degeneration was reported, confirming the biocompatibility and safety of grafted system.

Preparation of combined hydrogel solution that is suitable to control the emission of odor pollutants from brownfield site and its control effects

Odor pollution caused by brownfield site has attracted increasing attention. However, to date, fewer suitable materials can be used to control the emission of odor pollutant from brownfield site during remediation. This study prepared a kind of combined hydrogel solution based on sodium alginate and carboxymethyl cellulose sodium (CHS-SC) and tested the possibility of its membrane in controlling the emission of three odor pollutants (trichloroethylene, dimethyl disulfide, and p-xylene) from polluted soil. Our results showed that CHS-SC membrane could effectively control the emission of three odor pollutants from polluted soil. Comparatively, CHS-SC membrane had higher control rates for three odor pollutants at high ambient temperature (32 °C), short storage time of CHS-SC (5 days, 25 °C), and low odor pollutant concentration (2 ml/kg soil) than at low ambient temperature (2 °C), long storage time of CHS-SC (10 d, 25 °C), and high odor pollutant concentration (4 ml/kg soil), respectively. CHS-SC membrane was degraded by 79.23% after 150 days in soil and slightly changed soil bacterial community, indicating that it had good biodegradability and environmental friendliness. In addition, CHS-SC cost was the lowest among the products with similar function. This study shows that CHS-SC is effective in short-timely controlling the emission of odor pollutants from brownfield site.

A pH responsive and superporous biocomposite hydrogel of Salvia spinosa polysaccharide-co-methacrylic acid for intelligent drug delivery

Herein, a drug delivery system (SSH-co-MAA) based on the mucilage from seeds of Salvia spinosa (SSH; polymer) and methacrylic acid (MAA; monomer) is introduced for the controlled delivery of venlafaxine HCl using a sustainable chemical approach. The optimized conditions for the designing of the ideal formulation (M4) of SSH-co-MAA were found to be 2.5% (w/w) of SSH, 30.0% (w/w) of MAA, 0.4% (w/w) of both N,N'-methylene-bis-acrylamide (MBA; cross-linker) and potassium persulfate (KPS; initiator). The structure characterization of SSH-co-MAA by Fourier transform infrared and solid-state CP/MAS ¹³C-NMR spectroscopy has confirmed the grafting of MAA onto SSH. The thermogravimetric analysis revealed that SSH-co-MAA is a stable entity before and after loading of the venlafaxine HCl-loaded SSH-co-MAA (VSSH-co-MAA). Scanning electron microscopy images of SSH-co-MAA after swelling then freeze drying showed the superporous nature of the hydrogel. The gel fraction (%) of SSH-co-MAA depended upon concentration of SSH, MAA, and MBA. The porosity (%) was increased with the increase in the concentration of SSH and decreased with the decrease in the concentration of MAA and MBA. The swelling indices, venlafaxine HCl loading, and release (24 h at the pH of the gastrointestinal tract) from VSSH-co-MAA were found to be dependent on the pH of the swelling media and the concentration of SSH, MAA, and MBA. The release of venlafaxine HCl followed non-Fickian diffusion mechanism. Conclusively, SSH-co-MAA is a novel material for potential application in targeted drug delivery applications.

Development and Evaluation of Sodium Alginate/Carbopol 934P-Co-Poly (Methacrylate) Hydrogels for Localized Drug Delivery

This research was carried out to create a pH-responsive polymeric system for the targeted drug delivery of Diloxanide furoate. It relied on sodium alginate (Na-Alg) and Carbopol 934P as building blocks. Using an aqueous free radical polymerization method, SCH1-SCH12 was created with varying polymer, MAA, and MBA input ratios. Positive outcomes were seen in the swelling and release profiles at higher pH levels. Hydrogel formation, as well as component compatibility, thermal stability, and Diloxanide furoate loading, were all validated by instrumental characterization. A drug loading percentage of 83.56% was determined, with the swelling reaching 743.19%. For the formulation with MBA, the gel fraction was 94.58%. The release of diloxanide furoate increased to 91.77% at neutral pH. The formulation containing Carbopol 934P provided the highest mucoadhesion force (3993.42 dynes/cm²). The created hydrogel has been shown to be biocompatible by toxicological testing of the network. Based on the findings, the created polymeric nexus proved promising for pH-dependent localized and regulated delivery of Diloxanide furoate.

Development and Optimization of Tamarind Gum-β-Cyclodextrin-g-Poly(Methacrylate) pH-Responsive Hydrogels for Sustained Delivery of Acyclovir

Acyclovir has a short half-life and offers poor bioavailability. Its daily dose is 200 mg five times a day. A tamarind gum and β-cyclodextrin-based pH-responsive hydrogel network for sustained delivery of acyclovir was developed using the free-radical polymerization technique. Developed networks were characterized by FTIR, DSC, TGA, PXRD, EDX, and SEM. The effect of varying feed ratios of polymers, monomers, and crosslinker on the gel fraction, swelling, and release was also investigated. FTIR findings confirmed the compatibility of the ingredients in a new complex polymer. The thermal stability of acyclovir was increased within the newly synthesized polymer. SEM photomicrographs confirmed the porous texture of hydrogels. The gel fraction was improved (from 90.12% to 98.12%) with increased reactant concentrations. The pH of the dissolution medium and the reactant contents affected swelling dynamics and acyclovir release from the developed carrier system. Based on the R2 value, the best-fit model was zero-order kinetics with non-Fickian diffusion as a release mechanism. The biocompatibility of the developed network was confirmed through hematology, LFT, RFT, lipid profile, and histopathological examinations. No sign of pathology, necrosis, or abrasion was observed. Thus, a pH-responsive and biocompatible polymeric system was developed for sustained delivery of acyclovir to reduce the dosing frequency and improve patient compliance.

Extracellular vesicle: A magic lamp to treat skin aging, refractory wound, and pigmented dermatosis?

Exposure of the skin to an external stimulus may lead to a series of irreversible dysfunctions, such as skin aging, refractory wounds, and pigmented dermatosis. Nowadays, many cutaneous treatments have failed to strike a balance between cosmetic needs and medical recovery. Extracellular vesicles (EVs) are one of the most promising therapeutic tools. EVs are cell-derived nanoparticles that can carry a variety of cargoes, such as nucleic acids, lipids, and proteins. They also have the ability to communicate with neighboring or distant cells. A growing body of evidence suggests that EVs play a significant role in skin repair. We summarize the current findings of EV therapy in skin aging, refractory wound, and pigmented dermatosis and also describe the novel engineering strategies for optimizing EV function and therapeutic outcomes.

Polyvinylpyrrolidone K-30-Based Crosslinked Fast Swelling Nanogels: An Impeccable Approach for Drug's Solubility Improvement

Poor solubility is a global issue of copious pharmaceutical industries as large number of drugs in development stage as well as already marketed products are poorly soluble which results in low dissolution and ultimately dosage increase. Current study is aimed at developing a polyvinylpyrrolidone- (PVP-K30-) based nanogel delivery system for solubility enhancement of poorly soluble drug olanzapine (OLP), as solubilization enhancement is the most noteworthy application of nanosystems. Crosslinking polymerization with subsequent condensation technique was used for the synthesis of nanogels, a highly responsive polymeric networks in drug's solubility. Developed nanogels were characterized by percent entrapment efficiency, sol-gel, percent swelling, percent drug loaded content (%DLC), percent porosity, stability, solubility, in vitro dissolution studies, FTIR, XRD, and SEM analysis. Furthermore, cytotoxicity study was conducted on rabbits to check the biocompatibility of the system. Particle size of nanogels was found with 178.99 ± 15.32 nm, and in vitro dissolution study exhibited that drug release properties were considerably enhanced as compared to the marketed formulation OLANZIA. The solubility studies indicated that solubility of OLP was noticeably improved up to 36.7-fold in phosphate buffer of pH 6.8. In vivo cytotoxicity study indicated that prepared PVP-K30-based formulation was biocompatible. On the basis of results obtained, the developed PVP-K30-co-poly (AMPS) nanogel delivery system is expected to be safe, effective, and cost-effective for solubility improvement of poorly soluble drugs.

Synthesis of Chemically Cross-Linked pH-Sensitive Hydrogels for the Sustained Delivery of Ezetimibe

In recent years, pH-sensitive hydrogels have been developed for the delivery of therapeutic agents to specific target sites that have a defined pH range. The use of pH-responsive polymers in hydrogels allows drug delivery to the desired pH range of the target organ. The primary aim is to increase the retention time of the drug in the small intestine by utilizing the swelling mechanism of the hydrogel at intestinal pH. In this study, polyethylene glycol (PEG) was used as a polymer to formulate a pH-sensitive hydrogel of Ezetimibe to deliver the drug to the small intestine where it inhibits the absorption of cholesterol. Design Expert software was applied to design and optimize the trial formulations in order to obtain an optimized formulation that has all the desired characteristics of the hydrogels. The PEG/Acrylic Acid hydrogels showed the maximum swelling at pH 6.8, which is consistent with the pH of the small intestine (pH 6–7.4). The maximum entrapment efficiency of the hydrogels was 99%. The hydrogel released 80–90% of the drug within 24 h and followed first-order release kinetics, which showed that the release from the drug was sustained. Hence, the results showed that the choice of a suitable polymer can lead to the development of an efficient drug-loaded hydrogel that can deliver the drug at the specific pH of the target organ.

Orally Administered, Biodegradable and Biocompatible Hydroxypropyl–β–Cyclodextrin Grafted Poly (Methacrylic Acid) Hydrogel for pH Sensitive Sustained Anticancer Drug Delivery

In the current study, a pH sensitive intelligent hydroxypropyl–β–cyclodextrin-based polymeric network (HP-β-CD-g-MAA) was developed through a solution polymerization technique for site specific delivery of cytarabine in the colonic region. Prepared hydrogel formulations were characterized through cytarabine loading (%), ingredient’s compatibility, structural evaluation, thermal integrity, swelling pattern, release behavior and toxicological profiling in rabbits. Moreover, the pharmacokinetic profile of cytarabine was also determined in rabbits. New polymer formation was evident from FTIR findings. The percentage loaded into the hydrogels was in the range of 37.17–79.3%. Optimum swelling ratio of 44.56 was obtained at pH 7.4. Cytarabine release was persistent and in a controlled manner up to 24 h. In vitro degradation of hydrogels was more pronounced at intestinal pH as compared to acidic pH. Toxicity studies proved absence of any ocular, skin and oral toxicity, thus proving biocompatibility of the fabricated network. Hydrogels exhibited longer plasma half-life (8.75 h) and AUC (45.35 μg.h/mL) with respect to oral cytarabine solution. Thus, the developed hydrogel networks proved to be excellent and biocompatible cargo for prolonged and site-specific delivery of cytarabine in the management of colon cancer.

Biofunctional Hyaluronic Acid/κ-Carrageenan Injectable Hydrogels for Improved Drug Delivery and Wound Healing

The in situ injectable hydrogel system offers a widespread range of biomedical applications in prompt chronic wound treatment and management, as it provides self-healing, maintains a moist wound microenvironment, and offers good antibacterial properties. This study aimed to develop and evaluate biopolymer-based thermoreversible injectable hydrogels for effective wound-healing applications and the controlled drug delivery of meropenem. The injectable hydrogel was developed using the solvent casting method and evaluated for structural changes using proton nuclear magnetic resonance, Fourier transforms infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. The results indicated the self-assembly of hyaluronic acid and kappa-carrageenan and the thermal stability of the fabricated injectable hydrogel with tunable gelation properties. The viscosity assessment indicated the in-situ gelling ability and injectability of the hydrogels at various temperatures. The fabricated hydrogel was loaded with meropenem, and the drug release from the hydrogel in phosphate buffer saline (PBS) with a pH of 7.4 was 96.12%, and the simulated wound fluid with a pH of 6.8 was observed to be at 94.73% at 24 h, which corresponds to the sustained delivery of meropenem. Antibacterial studies on P. aeruginosa, S. aureus, and E. coli with meropenem-laden hydrogel showed higher zones of inhibition. The in vivo studies in Sprague Dawley (SD) rats presented accelerated healing with the drug-loaded injectable hydrogel, while 90% wound closure with the unloaded injectable hydrogel, 70% in the positive control group (SC drug), and 60% in the negative control group was observed (normal saline) after fourteen days. In vivo wound closure analysis confirmed that the developed polymeric hydrogel has synergistic wound-healing potential.

Formulation and evaluation of interpenetrating polymeric network for controlled drug delivery

Novel Cytarabine-loaded agarose and fenugreek-based hydrogel were formulated via the crosslinking process. Graft copolymerization of methacrylic acid (MAA) on agarose and fenugreek was carried out by using methylene bisacrylamide (MBA) as a crosslinker and potassium persulfate as an initiator. The influence of different formulation ingredients (fenugreek, agarose, MBA, MAA) on swelling index, percentage drug release, and percentage gel content were investigated. It was observed that an increase in the concentration of fenugreek and agarose resulted in an increase in the swelling index (72.45-97.17%). However, an increase in the amount of MBA led to a decrease in the swelling index from 74.23% to 57.74%. A similar result tendency was noted in the case of drug release. FTIR was employed to elucidate effective grafting. The thermal behavior of hydrogel was evaluated through TGA and DSC analysis whereas surface morphology was elucidated through SEM. Release studies were performed at both acidic and basic pH, that is, 1.2 and 7.4. Hence, formulated biocompatible hydrogels proved to be a promising system for the controlled delivery of Cytarabine.

Formulation, In Vitro Evaluation, and Toxicity Studies of A. vulgaris-co-AAm Carrier for Vildagliptin

This study investigated the use of Artemisia vulgaris L. seed mucilage as a new excipient for sustained delivery of Vildagliptin. Copolymeric carrier of A. vulgaris seed mucilage-co-AAm was devised by using acrylamide (AAm) as a monomer, methylene-bis-acrylamide (MBA) as a crosslinker, and potassium persulfate (KPS) as an initiator through free radical polymerization. Different formulations of A. vulgaris-co-AAm were devised by varying contents of polymer, monomer, crosslinking agent, initiator, and reaction temperature. Copolymeric structures were characterized through XRD analysis, Fourier transform infrared (FTIR) spectroscopy, TGA and DSC analysis, and scanning electron microscopy. Porosity, gel fraction, and Vildagliptin loading capacity of copolymers were also established. Swelling and in vitro drug release studies were conducted. XRD evaluation showed the alteration of the crystalline structure of Vildagliptin into an amorphous form. FTIR analysis confirmed the successful grafting of AAm to A. vulgaris seed mucilage backbone. Porosity was increased with increasing polymer concentration and reaction temperature while it was decreased with an increasing amount of AAm, MBA, and KPS. Gel content was decreased with increasing polymer concentration and reaction temperature while it was increased with an increasing amount of AAm, MBA, and KPS. Acute oral toxicity of copolymeric network was done in animal models to evaluate the safety. Copolymers showed the same swelling behavior at all pH 1.2, 4.5, 6.8, and 7.4. Vildagliptin release from copolymer showed a cumulative trend by increasing polymer content and reaction temperature, while a declining trend was observed with increasing contents of monomer, crosslinking agent, and initiator. Sustained release of Vildagliptin was observed from copolymers and release followed the Korsmeyer-Peppas model. From the acute oral toxicity studies, it is evident that newly synthesized copolymeric carriers are potentially safe for eyes, skin, and vital organs.

Improved drug delivery and accelerated diabetic wound healing by chondroitin sulfate grafted alginate-based thermoreversible hydrogels

Injectable hydrogels with multifunctional tunable properties comprising biocompatibility, anti-oxidative, anti-bacterial, and/or anti-infection are highly preferred to efficiently promote diabetic wound repair and its development remains a challenge. In this study, we report chondroitin sulphate (CS) and sodium alginate (SA)-based injectable hydrogel using solvent casting method loaded with curcumin that could potentiate reepithelization, increase angiogenesis, and collagen deposition at wound microenvironment to endorse healing cascade. The physical interaction and self-assembly of chondroitin sulfate grafted alginate (CS-Alg-g-PF127) hydrogel were confirmed using nuclear magnetic resonance (¹H NMR) and Fourier transformed infrared spectroscopy (FT-IR), and cytocompatibility was confirmed by fibroblast viability assay. The Masson's trichrome (MT) and hematoxylin and eosin (H&E) results revealed that blank chondroitin sulfate grafted alginate (CS-Alg-g-PF127) and CUR loaded CS-Alg-g-PF127 hydrogel had promising tissue regenerative ability, and showing enhanced wound healing compared to other treatment groups. The controlled release of CUR from injectable hydrogel was evaluated by drug release studies and pharmacokinetic profile (PK) using high-performance liquid chromatography (HPLC) that exhibited the mean residence time (MRT) and area under the curve (AUC) was increased up to 16.18 h and 203.64 ± 30.1 μg/mL*h, respectively. Cytotoxicity analysis of the injectable hydrogels using 3 T3-L1 fibroblasts cells and in vivo toxicity evaluated by subcutaneous injection for 24 h followed by histological examination, confirmed good biocompatibility of CUR loaded CS-Alg-g-PF127 hydrogel. Interestingly, the results of in vivo wound healing by injectable hydrogel showed the upregulation of fibroblasts-like cells, collagen deposition, and differentiated keratinocytes stimulating dermo-epidermal junction, which might endorse that they are potential candidates for excisional wound healing models.

Synthesis of PEG-4000-co-poly (AMPS) nanogels by cross-linking polymerization as highly responsive networks for enhancement in meloxicam solubility

Poor solubility is an ongoing issue and the graph of poorly soluble drugs has increased markedly which critically affect their dissolution, bioavailability, and clinical effects. This common issue needs to be addressed, for this purpose a series of polyethylene glycol (PEG-4000) based nanogels were developed by free radical polymerization technique to enhance the solubility, dissolution, and bioavailability of poorly soluble drug meloxicam (MLX), as improved solubility is the significant application of nanosystems. Developed nanogels formulations were characterized by FTIR, XRD, SEM, zeta sizer, percent equilibrium swelling, drug loaded content (DLC), drug entrapment efficiency (DEE), solubility studies, and in vitro dissolution studies. Furthermore, cytotoxicity studies were conducted in order to determine the bio-compatibility of the nanogels drug delivery system to biological environment. Nanogels particle size was found to be 156.19 ± 09.33 d.nm. Solubility study confirmed that the solubility of poorly soluble drug MLX was significantly enhanced up to 36 folds as compared to reference product (Mobic^®). The toxicity study conducted on rabbits and MTT assay endorsed the safety of the developed nanogels formulations to the biological system.

Bio-functional hydrogel membranes loaded with chitosan nanoparticles for accelerated wound healing

Wounds are often recalcitrant to traditional wound dressings and a bioactive and biodegradable wound dressing using hydrogel membranes can be a promising approach for wound healing applications. The present research aimed to design hydrogel membranes based on hyaluronic acid, pullulan and polyvinyl alcohol and loaded with chitosan based cefepime nanoparticles for potential use in cutaneous wound healing. The developed membranes were evaluated using dynamic light scattering, proton nuclear magnetic resonance, Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. The results indicated the novel crosslinking and thermal stability of the fabricated hydrogel membrane. The in vitro analysis demonstrates that the developed membrane has water vapors transmission rate (WVTR) between 2000 and 2500 g/m²/day and oxygen permeability between 7 and 14 mg/L, which lies in the range of an ideal dressing. The swelling capacity and surface porosity to liberate encapsulated drug (cefepime) in a sustained manner and 88% of drug release was observed. The cefepime loaded hydrogel membrane demonstrated a higher zone of inhibition against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli and excisional rat model exhibit expeditious recovery rate. The developed hydrogel membrane loaded with cefepime nanoparticles is a promising approach for topical application and has greater potential for an accelerated wound healing process.

Potential Applications of Nanomaterials and Technology for Diabetic Wound Healing

Diabetic wound shows delayed and incomplete healing processes, which in turn exposes patients to an environment with a high risk of infection. This article has summarized current developments of nanoparticles/hydrogels and nanotechnology used for promoting the wound healing process in either diabetic animal models or patients with diabetes mellitus. These nanoparticles/hydrogels promote diabetic wound healing by loading bioactive molecules (such as growth factors, genes, proteins/peptides, stem cells/exosomes, etc.) and non-bioactive substances (metal ions, oxygen, nitric oxide, etc.). Among them, smart hydrogels (a very promising method for loading many types of bioactive components) are currently favored by researchers. In addition, nanoparticles/hydrogels can be combined with some technology (including PTT, LBL self-assembly technique and 3D-printing technology) to treat diabetic wound repair. By reviewing the recent literatures, we also proposed new strategies for improving multifunctional treatment of diabetic wounds in the future.

Nanoparticle Interactions with the Tumor Microenvironment

Compared to normal tissues, the tumor microenvironment (TME) has a number of aberrant characteristics including hypoxia, acidosis, and vascular abnormalities. Many researchers have sought to exploit these anomalous features of the TME to develop anticancer therapies, and several nanoparticle-based cancer therapeutics have resulted. In this Review, we discuss the composition and pathophysiology of the TME, introduce nanoparticles (NPs) used in cancer therapy, and address the interaction between the TME and NPs. Finally, we outline both the potential problems that affect TME-based nanotherapy and potential strategies to overcome these challenges.

Biopolymer-based biomaterials for accelerated diabetic wound healing: A critical review

Non-healing, chronic wounds place a huge burden on healthcare systems as well as individual patients. These chronic wounds especially diabetic wounds will ultimately lead to compromised mobility, amputation of limbs and even death. Currently, wounds and limb ulcers associated with diabetes remain significant health issues; the associated healthcare cost ultimately leads to the increased clinical burden. The presence of diabetes interrupts a highly coordinated cascade of events in the wound closure process. Advances in the understanding of pathophysiological conditions associated with diabetic wounds lead to the development of drug delivery systems which can enhance wound healing by targeting various phases of the impaired processes. Wound environments typically contain degradative enzymes, along with an elevated pH and demonstrate a physiological cascade involved in the regeneration of tissue, which requires the application of an effective delivery system. This article aims to review the pathophysiological conditions associated with chronic and diabetic wounds. The delivery systems, involved in their treatment are described, highlighting potential biomaterials and polymers for establishing drug delivery systems, specifically for the treatment of diabetic wounds and the promotion of the associated mechanisms involved in advanced wound healing. Emerging approaches and engineered devices for effective wound care are reported. The discussion will give insight into the mechanisms relevant to all stages of wound healing.

Development and in vitro evaluation of (β-cyclodextrin-g-methacrylic acid)/Na+-montmorillonite nanocomposite hydrogels for controlled delivery of lovastatin

Background: Hyperlipidemia is the elevation of low density lipoprotein levels resulting in fat deposites in arteries and their hardening and blockage.  It is the leading cause of several life threatening pathological conditions like hypertension, cardiovascular diseases, diabetes etc. Purpose: The objective of this study was to prepare and optimize nontoxic, biocompatible β-CD-g-MAA/Na+-MMT nanocomposite hydrogels with varying content of polymer, monomer and montmorillonite. Moreover, lipid lowering potentials were determined and compared with other approaches. Methods: β-CD-g-MAA/Na+-MMT nanocomposite hydrogels (BM-1 to BM9) were prepared through free radical polymerization by using  β-CD  as polymer, MAA as monomer, MBA as crosslinker and montmorillonite as clay. Developed networks were evaluated for FTIR, DSC, TGA, PXRD, SEM, sol-gel fraction (%), swelling studies, antihyperlipidemic studies and toxicity studies. Results: Optimum swelling (94.24%) and release (93.16%) were obtained at higher pH values. Based on R2 and "n" value LVT release followed zero order kinetics with Super Case II transport release mechanism, respectively. Tensile strength and elongation at break were found to be 0.0283MPa and 94.68%, respectively. Gel fraction was between 80.55 - 98.16%. Antihyperlipidemic studies revealed that LDL levels were markedly reduced from 522.24 ± 21.88mg/dl to 147.63 ± 31.5mg/dl. Toxicity studies assured the safety of developed network. Conclusion: A novel pH responsive crosslinked network containing β-CD - g - poly (methacrylic acid) polymer and MMT was developed and optimized with excellent mechanical, swelling and release properties and lipid lowering potentials.