Obtaining and studying the properties of a polyvinyl alcohol/sodium alginate hydrogels

Sodium alginate (SA), due to its properties, including its ability to form pH-sensitive hydrogels, is a promising material as a potential platform for gut targeted delivery systems. However, pure sodium alginate systems have serious drawbacks. Firstly, this is the leakage of substances during the formation of the gel due to the long immersion time, which reduces the efficiency of encapsulation and secondly, the drug is released from the matrix too quickly. The development of drug delivery systems based on mixtures of sodium alginate and polyvinyl alcohol (PVA) can help solve these problems. Hydrogels based on a mixture of polyvinyl alcohol and sodium alginate can have great potential for use as functional biomaterials, therefore, studying the effect of the preparation method and mixture composition on the properties of the obtained materials is an urgent task. In this paper, hydrogels were obtained from a PVA/SA mixture with different SA content. The samples were obtained in two stages: first, a mixture of aqueous solutions of PVA/SA was subjected to several freeze-thaw cycles to physically crosslink the PVA chains to form a cryogel, and then in the matrix of the obtained PVA cryogel, the SA chains were crosslinked with calcium ions to form interpenetrating networks of PVA and SA. We investigated the swelling properties of the obtained PVA/SA hydrogels by measuring the swelling coefficient of predried hydrogel samples at different times of immersion in distilled water at 37°C. All samples had a similar tendency to swelling, and an increase in the content of polyvinyl alcohol in the mixture led to an increase in the equilibrium swelling constant of the mixture. In paper, the properties of the obtained PVA / AN hydrogels were investigated by measuring the swelling parameters of the tested hydrogel samples at different times of immersion in distilled water at 37 ° C. The process of release of a model compound (chloramphenicol) from PVA / AN polymer matrices was also studied. All samples had a similar tendency to swelling; an increase in the amount of polyvinyl alcohol in the mixture led to an increase in the equilibrium swelling constant of the mixture. The release of chloramphenicol in the pH 7.4 buffer solution was much higher than in the pH 1.2 solution, and with an increase in the PVA content in the mixture, the drug release rate decreased.

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