Effect of Charged and Non-ionic Membrane Additives on Physicochemical Properties and Stability of Niosomes

Abstract

The aim of this study was to investigate an influence of different types of membrane additives including negative charge (dicetylphosphate, DCP), positive charge (stearylamine, STR) and non-ionic molecule (cholesteryl poly-24-oxyethylene ether, SC24) on the physicochemical properties of drug-free and drug-loaded niosomes. Salicylic acid having different proportions of ionized and unionized species at different pH was selected as a model drug. The niosomes were composed of 1:1 mole ratio of Span 60: cholesterol as vesicle forming agents. The results show that incorporation of salicylic acid to the niosomes did not affect zeta potential values; however, addition of the membrane additives changed the zeta potential depending on the type of the additives. Transmission electron microscopy revealed that niosomes had unilamellar structure. The particle sizes of all developed niosomes were between 217 to 360 nm. The entrapment efficiency (%E.E.) of all salicylic acid niosomes at pH 3 was higher than that of niosomes at pH 5, indicating that salicylic acid in unionized form was preferably incorporated in niosomes. Furthermore, the positively charged niosomes showed the highest %E.E. of salicylic acid owing to electrostatic attraction between STR and salicylic acid. After 3 months of storage at 4 degrees C, the particle size of the niosomes remained in the nanosize range except for DCP salicylic acid niosomes at pH 3 whose size increased due to an instability of DCP at low pH. In addition, all niosomes showed no leakage of the salicylic acid after 3 months of storage indicating the good stability.

Development of a novel niosomal system for oral delivery of Ginkgo biloba extract

“…All of the formulations showed negative zeta potential values, which could reflect adsorption of counter ions or preferential adsorption of hydroxyl ions at the niosomal surface. 36 The zeta potential was higher in the spray-dried niosomes than in the freeze-dried niosomes, indicating that the spray-dried niosomal powder was more stable against aggregation and fusion than the freeze-dried niosomal powder.…”

Niosomes: A Controlled and Novel Drug Delivery System

“…Various types of surfactants have been reported to form vesicles, and have the capacity to entrap and retain the hydrophilic and hydrophobic solute particles. [1][2][3] Niosomes mainly contain two types of components i.e., nonionic surfactant and the additives. The non-ionic surfactants form the vesicular layer and the additives used in niosome preparation are cholesterol and the charged molecules.…”

Preparation of Salicylic Acid Loaded Nanostructured Lipid Carriers Using Box-Behnken Design: Optimization, Characterization and Physicochemical Stability

“…The present of salicylic acid in the dispersion might attribute to the increase in zeta potential of NLCs-SA 17,19 . In general, the suspended particles are considered to be physically stable when the absolute value of zeta potential is above 30 mV because the system is dominantly stabilized by electrostatic repulsion.…”