Synthesis of sodium alginate based sprayable new soft gel system

Abstract

Chemical reaction of sodium alginate (Na-Alg) with o-aminobenzoic acid (OABA) and m-aminobenzoic acid (MABA) in the presence of 1-ethyl-3-[3-(dimethylamino)propyl]-carbodiimide hydrochloride (EDC) afforded amide derivatives capable of forming viscous hydrogel systems exhibiting thixotropic behaviour. Characterization of the amide materials was done by employing FT-IR and 13C NMR, wherein amide formation between Na-Alg and OABA or MABA was confirmed. The thixotropic behaviour was evaluated by rheology and viscometry showing superior thixotropicity of OABA based amide to its MABA counterpart. The characteristic of the soft gel turning into a flowing liquid on gentle stirring predisposes it for possible application as a delivery system or sprayable gel material for transporting small active molecules to the targeted locations in health and personal care formulations.