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Enteric-coated application on drug is used to prevent the drug from inactivation which are degraded by gastric enzyme. The present study is aimed at achieving controlled drug delivery in acidic medium of gastrointestinal tract (GIT) by enteric coating of hydroxy propyl methylcellulose (HPMC) and Eudragit L100 on carboxylated agarose hydrogel, creating a pH-dependent delivery system. Fourier-transformed infrared spectroscopy (FTIR) was for the detection of carboxylic group on agarose hydrogel, and scanning electron microscope (SEM) was used for the determination surface of prepared formulation. To check the pH sensitivity of enteric-coated formulation, different pH solution was used. It was found that the formulation was not dissolved in 1.2 but dissolve in pH 6.8 similarly; hydrogels lacking coating showed that tartrazine was more dissolved in pH 1.2, and less dissolved at pH 6.8. The release of tartrazine from the hydrogels was measured by using spectrophotometer and using a scanning electron microscope to examine the morphology and surface appearance of hydrogel capsules. This study revealed cracks on coated samples, while noncoated samples showed clear appearance with no cracks. Our findings revealed that this method could be useful for the development of an enteric coating drug delivery system., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2022 Muhammad Junaid Khan et al.)

Stimuli-responsive hydrogels have drawn increasing research interest in regenerative medicine due to their tunable molecular structures and functional properties for both providing a suitable microenvironment for wound healing and to serve as a sustainable therapeutic. Hence, we developed a stimuli-responsive drug-loaded hydrogel wound dressing for sustained, controlled release of the drug and accelerating wound healing. Hydrogel dressings with stimuli-responsive properties were prepared using carboxymethyl agarose (CMA) with various degrees of substitution and calcium ion crosslinking, followed by the loading of recombinant human epidermal growth factor (Rh-EGF) on the CMA hydrogel. Experimental results indicated that these hydrogel composites showed pH and temperature stimuli-responsive behaviors and released the encapsulated drug sustainedly in various release media. Moreover, the hydrogel dressings exhibited a porous network structure, stable physical properties, and excellent biocompatibility. The investigation in vivo showed that the Rh-EGF-loaded CMA hydrogel dressing significantly enhanced wound healing and reduced inflammatory responses by upregulating the transforming growth factor-beta, vascular endothelial growth factor, and cluster of differentiation 31 (CD31). These results confirm that Rh-EGF-loaded CMA hydrogel dressings possess potential application in accelerating wound healing and tissue regeneration.

Here, a novel double‐crosslinked hydrogel dressing with enhanced antibacterial and anti‐inflammatory activities is reported. Carboxymethyl chitosan is crosslinked with silane and Ca2+ to form a double‐crosslinked hydrogel, and silver nanoparticles are loaded to introduce antibacterial properties to the hydrogel. The covalent crosslinking preserves the integrity of the hydrogel matrix, while the ionic crosslinking dissipates the energy under deformation. It combines high stretchability, toughness, tissue adhesion, and antimicrobial function. This hydrogel exhibits excellent cytocompatibility and hemocompatibility. Moreover, in vitro and in vivo investigations demonstrate its efficacy in accelerating bacterial‐infected wound healing. Given its excellent cytocompatibility and mechanical properties, this hydrogel is anticipated to be widely used in bacteria‐associated wound management. [ABSTRACT FROM AUTHOR]

Here, a multifunctional film (MFF) as an alternative tissue adhesive in the form of an interpenetrating network consisting of self‐crosslinked aldehyde‐functionalized chitosan (AC) and crosslinked poly(acrylic acid) (PAA) further coordinated with Ag+ is reported. The MFF combines enhanced toughness and stretchability, which is attributed to the synergistic effects of the double‐network design. Covalent crosslinking maintains the overall integrity of the MFF matrix, while noncovalent crosslinking dissipates energy under deformation. Upon contact, the MFF quickly dries the tissue surface followed by instant physical crosslinking to the tissue. Subsequent covalent crosslinking between the aldehyde groups of the MFF and the primary amine groups on the surface of the tissue further stabilizes the adhesion. Meanwhile, Ag+ provides strong antibacterial properties to the MFF. Notably, in vivo studies demonstrate that the MFF allows facile and tough attachment to the wet and dynamic surface of rabbit liver and presents superior hemostasis and sealing properties. Furthermore, the MFF can be safely degraded without causing abnormal defects in vivo. The outstanding physicochemical properties of the MFF can potentially be a good alternative to existing sutures or staples and has potential for use in clinical practice. [ABSTRACT FROM AUTHOR]

Here, a novel macroporous hydrogel dressing is presented that can accelerate wound healing and guard against bacteria‐associated wound infection. Carboxymethyl agarose (CMA) is successfully prepared from agarose. The CMA molecular chains are cross‐linked by hydrogen bonding to form a supramolecular hydrogel, and the hydroxy groups in the CMA molecules complex with Ag+ to promote hydrogel formation. This hydrogel composite exhibits pH‐responsiveness and temperature‐responsiveness and releases Ag+, an antibacterial agent, over a prolonged period of time. Moreover, this hydrogel exhibits outstanding cytocompatibility and hemocompatibility. In vitro and in vivo investigations demonstrate that the hydrogel has enhanced antibacterial and anti‐inflammatory capabilities and can significantly accelerate skin tissue regeneration and wound closure. Astonishingly, the hydrogel can cause the inflammation process to occur earlier and for a shorter amount of time than in a normal process. Given its excellent antibacterial, anti‐inflammatory, and physicochemical properties, the broad application of this hydrogel in bacteria‐associated wound management is anticipated. [ABSTRACT FROM AUTHOR]

Macroporous Hydrogel Dressing: A Macroporous Hydrogel Dressing with Enhanced Antibacterial and Anti-Inflammatory Capabilities for Accelerated Wound Healing (Adv. Funct. Keywords: agarose; antibacterial; biopolymers; hydrogels; wound healing EN agarose antibacterial biopolymers hydrogels wound healing 1 1 1 05/23/20 20200520 NES 200520 In article number 2000644, Changhu Xue, Xiangzhao Mao, and co-workers develop a macroporous hydrogel dressing with antibacterial and anti-inflammatory properties for accelerated wound healing. Agarose, antibacterial, biopolymers, hydrogels, wound healing. [Extracted from the article]

Inspired by disulfide bonding mediated mucin adhesion, a probiotic delivery carrier with intestinal targeting and mucoadhesion properties is developed. Alginate is thiolated with cysteine and the hydrogel carrier is formed by self-assembling of thiolated alginate (alg-thiol) through disulfide bonding. The alg-thiol hydrogel can effectively protect probiotics against gastric acids and digestive enzymes in the stomach because of the protonation of the carboxyl groups and the survival ratio of probiotics increases about 105 times compared to that of unencapsulated probiotics. Then, deprotonation of the carboxyl groups results in swelling of the alg-thiol hydrogel and spontaneous release of the encapsulated probiotics in the small intestine. After arriving at the colon, the alg-thiol hydrogel quickly degrades under reducing condition, and completely releases rest of the encapsulated probiotics due to disruption of the disulfide bonds. • Alg-hydrogel shows pH/redox dual responsiveness. • The survival rate of encapsulated probiotics is increased by 106 times in SGF. • Alg-hydrogel has a mucoadhesive capacity. [ABSTRACT FROM AUTHOR]

Dialdehyde-based cross-linking agents are widely used in the cross-linking of amino group-containing macromolecules. However, the most commonly used cross-linking agents, glutaraldehyde (GA) and genipin (GP), have safety issues. In this study, a series of dialdehyde derivatives of polysaccharides (DADPs) were prepared by oxidation of polysaccharides, and their biocompatibility and cross-linking properties were tested using chitosan as a model macromolecule. The DADPs showed outstanding cross-linking and gelation properties comparable to GA and GP. The DADPs and hydrogels cross-linked with the DADPs exhibited excellent cytocompatibility and hemocompatibility with different concentrations while significant cytotoxicity was observed in GA and GP. The experimental results showed that the cross-linking effect of DADPs increased along with their oxidation degree. The outstanding cross-linking effect of the DADPs show a potential for use in the cross-linking of biomacromolecules with amino groups and could be an adequate alternative to existing cross-linkers. [ABSTRACT FROM AUTHOR]