Role of Temperature on the Size of Niosomes Formed by the Ether Injection Method

Niosomes are lamellar vesicles formed by self-association of non-ionic surfactants and cholesterol having good compatibility with the biological system and low toxicity. Their ability to encapsulate both hydrophilic and hydrophobic drugs, their potential use in protection of drugs, controlled release and targeted drug delivery makes them a promising drug delivery system. Various factors like nature of drug, amount and type of surfactant used, method of preparation, amount and charge of cholesterol used, type and volume of hydrating medium, speed of agitation, time and temperature of hydration medium affect the type and characteristics of niosomes formed. Therefore, a study was conducted to determine the effect of hydration temperature on the size of niosomes formed by ether injection method. Aceclofenac was used as the model drug as it is lipophilic and shows good encapsulation in niosomes. Span 20 was used as the non-ionic surfactant. The study was conducted at three temperatures of hydration and all the other variables were kept constant. The niosomes formed at the different hydration temperatures were evaluated for shape and size by optical microscopy and mean vesicle size determined at each temperature. The data obtained for size was statistically analysed by the software Graphpad prism version 7 using ordinary one-way ANOVA. The p value obtained (at 95% confidence interval: p< 0.05) was used to determine significant difference between the mean vesicle sizes at the three temperatures. The study showed that hydration temperature played a major role in the size of niosomes formed by ether injection method.