Investigating the effect of solvent polarity environment differences in electrolyte and non-electrolyte systems

To address the knowledge gap regarding the polarity of excipient solutions and the impact on biologically relevant systems, a comprehensive exploration of the polarity of solutions is essential. This study explores the solvatochromic response of Reichardt's dye to solvent polarity in aqueous solutions, focusing on structurally similar electrolytes and non-electrolytes at concentrations typically used in pharmaceutical formulations. UV absorbance measurements demonstrated sensitivity to subtle structural differences, such as counterion variations or glycosidic bonds. Here, chloride salts and disaccharides were analyzed and notable polarity differences between similar systems were found. Additionally, unexpected similarities between sodium chloride and trehalose were observed. This investigation underscores the potential of readily accessible solvent polarity and solvatochromic studies to deepen the understanding of aqueous solutions and extend their application to pharmaceutical excipients and their roles in protein formulation.