Physico-chemical interactions between negatively charged hyaluronan and positively charged surfactant result in self-assembly nanoparticles formation. These particles have a core-shell like structure and can be used in targeted delivery of hydrophobic active substances. A hydrophobic inner core contains aggregated surfactant molecules and hyaluronan create a hydrophilic shell layer.
The aim of our study was to prepare and study hyaluronic acid nanoparticles based on electrostatic interactions with oppositely charged surfactant molecules.
Interactions of hyaluronan and surfactants were investigated using dynamic light scattering and Laser Doppler Velocimetry methods. Titration experiments (size distribution and zeta potential measurement and isoelectric point) were utilized to explore the formation of aggregates. Hyaluronan or surfactant was used as titrant for creation of different type of aggregates. Effect of molecular weight of hyaluronan and ionic strength of solvent were investigated.
Aggregates formation is influenced by preparation of system. Different particles are formed if hyaluronan is added to surfactant solution or vice versa. Molecular weights of hyaluronan have inconsiderable effect on interactions of components. If hyaluronan have a role of titrant, final particles are smaller than in the case of surfactant as titrant and can be more suitable for drug delivery applications.
Presence of low molecular weight electrolyte in the system has a significant effect on isoelectric point achievement and stability of the system due to reduction of electrostatic repulsion between oppositely charged components.
Assuming in the isoelectric point is reached compensation of charges of hyaluronan and surfactant, real degrees of hyaluronan dissociation were determined. Concentration of hyaluronan and conformation of hyaluronan in the system have a significant effect on established degree of dissociation.
