This work reports synthesis of pH-responsive alginate/chitosan hydrogel spheres with the average diameter of 2.0 ± 0.05 mm, which contain cefotaxime that is an antibiotic of the cefalosporine group. The spheres provided the cefotaxime encapsulation efficiency of 95 ± 1%. An in vitro release of cefotaxime from the spheres in the media that simulate human biological fluids in peroral delivery conditions was found to be a pH-dependent process. The analysis of cefotaxime release kinetics by the Korsmeyer–Peppas model revealed a non-Fickian mechanism of its diffusion, which may be related to intermolecular interactions occurring between the antibiotic and chitosan. Conductometry, UV spectroscopy, and IR spectroscopy were used to study complexation of chitosan with cefotaxime in aqueous media with varied pH, characterize the composition of the complexes, and calculate their stability constants. The composition of the cefotaxime–chitosan complexes was found to correspond to the 1.0:4.0 and 1.0:2.0 molar ratios of the components at pH 2.0 and 5.6, respectively. Quantum chemical modeling was used to evaluate energy characteristics of chitosan–cefotaxime complexation considering the influence of a solvent.

中文翻译：

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海藻酸盐/壳聚糖水凝胶作为头孢噻肟的透视运输系统

这项工作报告了平均直径为 2.0 ± 0.05 mm 的 pH 响应型藻酸盐/壳聚糖水凝胶球的合成，其中含有头孢噻肟（头孢菌素类抗生素）。该球体的头孢噻肟包封率为 95 ± 1%。头孢噻肟从模拟人体生物体液口服给药条件的介质中的球体的体外释放被发现是一个 pH 依赖性过程。通过 Korsmeyer-Peppas 模型对头孢噻肟释放动力学的分析揭示了其扩散的非菲克机制，这可能与抗生素和壳聚糖之间发生的分子间相互作用有关。利用电导法、紫外光谱和红外光谱研究了壳聚糖与头孢噻肟在不同 pH 值的水介质中的络合情况，表征了络合物的组成，并计算了其稳定常数。发现头孢噻肟-壳聚糖复合物的组成在pH 2.0和5.6下分别对应于1.0:4.0和1.0:2.0的组分摩尔比。考虑溶剂的影响，使用量子化学模型评估壳聚糖-头孢噻肟络合的能量特性。