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Gellan gum (GG) emerges as a promising candidate for developing polymeric carriers with extended retention on the ocular surface, aiming to enhance the efficacy of topical ocular drug delivery systems. This study undertakes the purification of commercial GG through fractional dissolution and ultrasonic treatment, producing fractions characterized by 1H, 13C NMR, FTIR spectroscopy and thermogravimetric analysis. The intrinsic viscosity of GG samples was measured in a 0.025 M tetramethylammonium chloride solution and their molecular weights were calculated via the Mark‐Kuhn‐Houwink equation. Methodological choices regarding synthetic procedures, solvents and reagents were guided by considerations of biocompatibility, aligning with the end goal of drug delivery applications. The study further explores the mucoadhesive potential of GG fractions with varying molecular weights for ocular drug delivery, utilizing an in vitro flow‐through technique with fluorescent detection on freshly excised bovine corneal mucosa surfaces. The findings under‐score the viability of GG formulations in enhancing ocular drug retention and pave the way for future applications in topical ocular therapeutics. [ABSTRACT FROM AUTHOR]

Commercial low acyl gellan (LAG) is purified by the fractional dissolution method. An aqueous solution of purified commercial LAG exhibits polyelectrolyte character due to its high molar mass and carboxylic groups in glucuronic acid fragments. The empirical Fuoss equation determines the intrinsic viscosity of purified LAG in salt‐less water. Fractionation of commercial LAG is carried out by ultrasound treatment. LAG fractions are characterized by 1H NMR and FTIR spectroscopy. The intrinsic viscosities of ultrasonically treated LAG samples are measured in 0.025 m of tetramethylammonium chloride (TMACl). The molecular weights of LAG fractions are determined by the Mark–Kuhn–Houwink equation. [ABSTRACT FROM AUTHOR]

Gellan gum prepared from the domestic raw materials of Kazakhstan is studied by methods of 1H NMR spectroscopy, FTIR, GPC, TGA, and compared with characteristics of commercial gellan gum. Fermentation on glucose‐fructose syrup of Zharkent and Burunday corn starch plants (Kazakhstan) by Sphingomonas paucimobilis ATCC 31461 produces a biomass containing a high acyl gellan gum (HAG). The average molecular weights, Mw, Mn, Mz, and polydispersity index (PDI) of HAG are determined by GPC. Low acyl gellan (LAG) is obtained by treatment of HAG with alkaline solution. It is shown that the spectral and thermal characteristics of HAG and LAG produced from the glucose‐fructose syrup and commercial gellan gum are similar. [ABSTRACT FROM AUTHOR]

ABSTRACT Macroporous amphoteric cryogels based on N, N-dimethylaminoethylmethacrylate and methacrylic acid p(DMAEM- co-MAA) crosslinked by N, N′-methylenebisacrylamide (MBAA) were synthesized by radical copolymerization of monomer mixtures in cryoconditions. The structure and morphology of cryogels were evaluated by FTIR and SEM. Cryogels exhibited interconnected porous structure with pore size ranging from 40 to 80 µm, which depended on their crosslinking degree. The value of the isoelectric point (IEP) of equimolar amphoteric cryogel determined from the water flux was equal to 4.4, while the IEP of cryogel with the excess of DMAEM units was equal to 7.1. The mechanical strength of equimolar amphoteric cryogels increases with increasing amount of crosslinking agent. The complexation ability of amphoteric cryogels with respect to surfactant, dyes, and protein was demonstrated. The adsorption isotherms with respect to anionic surfactant-sodium dodecylbenzene sulfonate (SDBS) and protein-lysozyme correspond to Langmuir equation, while adsorption isotherms of anionic and cationic dyes-methylene blue (MB) and methyl orange (MO) are well described by Freundlich equation. It was found that the binding ability of p(DMAEM- co-MAA) with respect to various low- and high-molecular weight compounds changes in the following order: SDBS > lysozyme ≫ MO > MB. The preferential adsorption of MB from the mixture of protein and MB was shown. The quantitative release of protein, surfactant and dye molecules from the matrix of cryogels takes place at the IEP of cryogel. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43784. [ABSTRACT FROM AUTHOR]