Exploration of arabinogalactan of gum polysaccharide potential in hydrogel formation and controlled drug delivery applications

Functionalization of almond gum through covalent and non-covalent interactions for biomedical applications

The versatile properties of carbohydrate polymers make them a relevant, promising precursor to design innovative materials for use in biomedical applications. Recent research mainly focuses on the development of the polysaccharide based functional materials. Hydrogel derived materials are a source of great motivation for the development of drug delivery (DD) carriers with inherent therapeutic potential. Herein, almond gum-based hydrogels were synthesized for the delivery of the anticancer drug methotrexate after impregnation to improve the DD profile. Hydrogels were characterized by FESEM, EDS, AFM, 13C NMR, FTIR, TGA, DSC, XRD, mechanical strength & biomedical assay. The optimized network hydrogel exhibited a mesh size of 19.764 mm and a cross-linking density of 5.002 × 10-5 mol/cm3 of the hydrogels. Morphological features revealed irregular, uneven internal morphology of hydrogels in FE-SEM. The inclusion of sulphated and amide polymers in hydrogels was found in elemental composition (C = 60.72 %, O = 29.79 %, N = 6.63 % and S = 2.86 %) of hydrogels inferred from EDS. Spectroscopic characterization by FT-IR and 13C NMR confirmed the inclusion of PVP and PVSA through grafting reaction. The crosslinked product formed was found thermally stable and amorphous in nature through TGA and XRD analysis. The sustained release was found through supramolecular interactions and release complied a non-Fickian mechanism for drug diffusion (n = 0.73) and the release profile was best described by the Hixson-Crowell kinetic model in colonic pH. The hydrogels were mucoadhesive in nature and required 144 ± 10.54 mN force for the separation of hydrogels from the mucosal surface during the adhesion test. Hydrogel illustrated antioxidant activity (32.68 ± 0.83 μg GAE) during their radical scavenging test by FC reagent assay. Drug encapsulated hydrogels demonstrated antimicrobial efficacy against microbes. The results of physico-chemical and biomedical properties of hydrogels suggested their suitability for biomedical uses.

Immobilization of α-amylase in calcium alginate-gum odina (CA-GO) beads: An easily recoverable and reusable support

A natural polysacharide, gum odina was collected from Odina wodier tree and purified. Purified gum odina was used with sodium alginate for immobilization of α-amylase. Calcium alginate-gum odina (CA-GO) beads were prepared by ionotropic gelation method to find the improvement of immobilization efficiency and reusability of α-amylase over calcium alginate (CA) beads. XRD, SEM, FTIR, beads diameter, enzyme leaching from beads, moisture content, total soluble matter and swelling study have been carried out to understand the physical morphology and mechanism of immobilization of enzyme in beads matrix. It has been observed that if the polymer ratio changes (keeping enzyme conc. & calcium Chloride conc. constant) then the size and shape of the beads will vary and at a particular range of polymer ratio, the optimal beads forms. At a certain conc.(4%w/v of SA and 1%w/v GO), the immobilization efficiency of CA-GO and CA beads were 92.71 ± 0.85 % (w/w) and 89.19 ± 0.35 %(w/w) respectively. After 8th time use, the CA-GO beads remain (~4 fold) more active than that of CA beads. The FTIR confirms that GO does not interfere with α-Amylase and alginate. Here, it can be concluded that CA-GO beads show better efficiency in respect to immobilization, reusability than CA beads only.

Antioxidant Activities of Natural Polysaccharides and Their Derivatives for Biomedical and Medicinal Applications

Many chronic diseases such as Alzheimer's disease, diabetes, and cardiovascular diseases are closely related to in vivo oxidative stress caused by excessive reactive oxygen species (ROS). Natural polysaccharides, as a kind of biomacromolecule with good biocompatibility, have been widely used in biomedical and medicinal applications due to their superior antioxidant properties. In this review, scientometric analysis of the highly cited papers in the Web of Science (WOS) database finds that antioxidant activity is the most widely studied and popular among pharmacological effects of natural polysaccharides. The antioxidant mechanisms of natural polysaccharides mainly contain the regulation of signal transduction pathways, the activation of enzymes, and the scavenging of free radicals. We continuously discuss the antioxidant activities of natural polysaccharides and their derivatives. At the same time, we summarize their applications in the field of pharmaceutics/drug delivery, tissue engineering, and antimicrobial food additives/packaging materials. Overall, this review provides up-to-date information for the further development and application of natural polysaccharides with antioxidant activities.

Preparation and characterization of starch-cellulose interpenetrating network hydrogels based on sequential Diels-Alder click reaction and photopolymerization

Herein, starch-cellulose interpenetrating network (IPN) hydrogels were fabricated by sequential Diels-Alder click reaction and photopolymerization in water. Moreover, β-cyclodextrin, a commonly used host molecule in supramolecular chemistry, was also introduced to improve the performance of the IPN hydrogel. Firstly, the starch-based dienes were synthesized by modifying starch with N-maleoyl-β-alanine, and the cellulose-based dienophiles were obtained by the reaction of cellulose and furfurylamide succinate; Secondly, the as-synthesized starch-based dienes, cellulose-based dienophiles, polymerizable β-cyclodextrin, crosslinker, and acrylamide were dissolved in water and obtained a transparent solution. The solution was maintained in a water bath of 50 °C for 3 h, forming the first network via catalyst-free click Diels-Alder reaction, subsequently, the second network was formed by photopolymerization. Their preparation conditions were optimized via one-factor experiments and their properties and structures were characterized. Finally, 5- fluorouracil (5-Fu) was used as a model drug to study the sustained release behavior of the drug-loaded hydrogels. Release profile was found to fit in Ritger-Peppas kinetic model and polymer relaxation and drug diffusion made a valuable contribution to drug release. Taking into account the virtues of easily controllable photopolymerization and catalyst-free Diels-Alder reaction, the strategy described here has a potential application in the preparation of IPN hydrogels.

Hydrogels as Drug Delivery Systems: A Review of Current Characterization and Evaluation Techniques

Owing to their tunable properties, controllable degradation, and ability to protect labile drugs, hydrogels are increasingly investigated as local drug delivery systems. However, a lack of standardized methodologies used to characterize and evaluate drug release poses significant difficulties when comparing findings from different investigations, preventing an accurate assessment of systems. Here, we review the commonly used analytical techniques for drug detection and quantification from hydrogel delivery systems. The experimental conditions of drug release in saline solutions and their impact are discussed, along with the main mathematical and statistical approaches to characterize drug release profiles. We also review methods to determine drug diffusion coefficients and in vitro and in vivo models used to assess drug release and efficacy with the goal to provide guidelines and harmonized practices when investigating novel hydrogel drug delivery systems.

Moringa gum and its modified form as a potential green polymer used in biomedical field

Over the past few decades, natural gums are extensively investigated by the researchers due to their beneficial physicochemical properties. Among them, the polysaccharide exudates obtained from the stem of the plant Moringa oleifera, known as moringa gum, is investigated widely in the food, pharmaceutical, and other areas. The moringa gum is used in the form of dried powder as a pharmaceutical excipient in various formulations. It is also derivatized either by grafting or by other chemical modifications for enhancing its properties. The research on moringa gum and modified moringa gum has diversified in numerous biomedical fields. However, summarization of these progress are not available in the literature. This article gives an overview of the collection, purification, structural elucidation, and modification of moringa gum. Moreover, the present review furnishes complete information on the various aspects of moringa gum and its applications in various industrial and biomedical fields.

Surface Morphology and Physicochemical Characterization of Thermostable Moringa Gum: A Potential Pharmaceutical Excipient

An efficient protocol for physico-chemical characterization of gum exudates collected from the drumstick tree (Moringa oleifera Lam.) has been reported in the present study. Extraction of gum metabolites was done using a series of water, alcohol, acid, and alkali solvent systems. The gum was sparingly soluble in water at room temperature and formed a colloidal solution. Solubility of the gum gradually increased in the solvent gradient (80% ethanol, deionized water, 0.05 M HCl, and 0.05 M NaOH) at 90 °C. Further, electron microscopy revealed that the acetyl group is essential in maintaining the structural integrity, and deacetylation of gum resulted in formation of a mesh of scattered and fibrous particles. Treatment of gum with deionized water resulted in development of a hydrocolloidal matrix with a pore size of 0.5 μm, which upon deacetylation was reduced up to 0.2 μm. The polymer was amorphous in nature and showed maximum thermal stability in ethanol. Gas chromatography-mass spectrometry of the gum polymer revealed that carbohydrate derivatives constituted its major part (>75%). Maximum carbohydrate concentration was obtained in the ethanol soluble fraction, along with fatty acids (10%) and secondary metabolites (9%). The results provided very first confirmation of the hydrocolloidal properties and thermostability of the gum exudates obtained from the drumstick tree, which can further be used to develop an eco-friendly and nontoxic bioligand.