Exploration of nonionic surfactant based aggregates as controlled release vehicles

Abstract

Microstructural transitions occur frequently in water-soluble nonionic amphiphiles as solution temperature and solvent polarity change. This enables tuning of the assemblies at various length scales. Possible risks in lower order self-assembled systems include premature payload discharge, which can result in undesirable pharmacokinetic events and off-target effects. This is avoidable by transforming micelles into structurally robust vesicular assemblies. D-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS) has been widely employed as a solubilizer, permeation enhancer, emulsifier, bioavailability enhancer, and stabiliser in many self-assembly and dispersion systems because it is a nonionic amphiphile with a low critical micelle concentration (CMC) and excellent biosafety profile. In addition to making hydrophobic medications soluble, TPGS has apoptogenic and P-glycoprotein inhibitory action. As a result of these properties, possibility of creating its higher order assemblies were explored. It was combined with routinely consumed sugars glucose, mannose, and galactose. The incorporation of sugars for achieving higher order structures appears intriguing in formulation research as it avoids the use of chemical cross linking agents, initiators and catalysts. In addition, sodium cholate(a bile salt) was also tested. Using dynamic light scattering (DLS), small angle neutron scattering (SANS), electron microscopy, and nuclear magnetic resonance (NMR) techniques, these transitions were assessed in relation to the external parameters (namely; temperature, electrolytes, and pH). These aggregates were examined for loading and released characteristics using quercetin as a model natural antioxidant. Its release profile was examined using several mathematical models.The findings demonstrate that the micellar system was indeed transformed by bile salts, but monosaccharides supported the higher order transitioning accordance to their concentration and structure.