Bietsch Jonathan, Baker Logan, Duffney Anna, Mao Alice, Foutz Mary, Ackermann Cheandri, Wang Guijun
Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA 23529, USA.
Gels. 2023 May 27;9(6):445. doi: 10.3390/gels9060445.
Carbohydrate-based low molecular weight gelators (LMWGs) are compounds with the capability to self-assemble into complex molecular networks within a solvent, leading to solvent immobilization. This process of gel formation depends on noncovalent interactions, including Van der Waals, hydrogen bonding, and π-π stacking. Due to their potential applications in environmental remediation, drug delivery, and tissue engineering, these molecules have emerged as an important area of research. In particular, various 4,6--benzylidene acetal-protected D-glucosamine derivatives have shown promising gelation abilities. In this study, a series of C-2-carbamate derivatives containing a para-methoxy benzylidene acetal functional group were synthesized and characterized. These compounds exhibited good gelation properties in several organic solvents and aqueous mixtures. Upon removal of the acetal functional group under acidic conditions, a number of deprotected free sugar derivatives were also synthesized. Analysis of these free sugar derivatives revealed two compounds were hydrogelators while their precursors did not form hydrogels. For those protected carbamates that are hydrogelators, removal of the 4,6-protection will result in a more water-soluble compound that produces a transition from gel to solution. Given the ability of these compounds to form gels from solution or solution from gels in situ in response to acidic environments, these compounds may have practical applications as stimuli-responsive gelators in an aqueous medium. In turn, one hydrogelator was studied for the encapsulation and release of naproxen and chloroquine. The hydrogel exhibited sustained drug release over a period of several days, with the release of chloroquine being faster at lower pH due to the acid lability of the gelator molecule. The synthesis, characterization, gelation properties, and studies on drug diffusion are discussed.
基于碳水化合物的低分子量凝胶剂（LMWGs）是一类能够在溶剂中自组装成复杂分子网络，从而使溶剂固定化的化合物。这种凝胶形成过程依赖于非共价相互作用，包括范德华力、氢键和π-π堆积。由于它们在环境修复、药物递送和组织工程中的潜在应用，这些分子已成为一个重要的研究领域。特别是，各种4,6-亚苄基缩醛保护的D-葡萄糖胺衍生物已显示出有前景的凝胶化能力。在本研究中，合成并表征了一系列含有对甲氧基亚苄基缩醛官能团的C-2-氨基甲酸酯衍生物。这些化合物在几种有机溶剂和水性混合物中表现出良好的凝胶化性能。在酸性条件下去除缩醛官能团后，还合成了许多脱保护的游离糖衍生物。对这些游离糖衍生物的分析表明，有两种化合物是水凝胶剂，而它们的前体不形成水凝胶。对于那些作为水凝胶剂的受保护氨基甲酸酯，去除4,6-保护基将产生一种水溶性更高的化合物，导致从凝胶到溶液的转变。鉴于这些化合物能够在酸性环境中原位从溶液形成凝胶或从凝胶形成溶液，这些化合物可能作为水性介质中的刺激响应凝胶剂具有实际应用。反过来，对一种水凝胶剂进行了萘普生和氯喹的包封和释放研究。该水凝胶在几天内表现出持续的药物释放，由于凝胶剂分子的酸敏感性，氯喹在较低pH下的释放更快。讨论了合成、表征、凝胶化性能以及药物扩散研究。
