Dermal targeting of Centella asiatica extract using hyaluronic acid surface modified niosomes.

The work aimed to develop Centella asiatica extract-loaded niosomes (CAE-Nio) and surface modified niosomes by hyaluronic acid (CAE-Nio-HA) to enhance transdermal penetration. Niosome formulations were prepared by film hydration method using Tween 60 and Span 60 as nonionic surfactants, cholesterol and various CAE contents. Various HA concentrations were investigated to obtain optimized CAE-Nio enhancing further skin penetration. Results showed that niosomes prepared from Tween 60 yielded suitable CAE encapsulated niosomes with mean particle size and zeta-potential of 155 nm and -15 mV, respectively. The niosomes exhibited high encapsulation efficiency (%EE) and drug loading capacity (%DL) of 71-77% and 3-7%, respectively. Incorporating HA to niosome decreased %DL and caused larger particle size and increased zeta-potential in a dose dependent manner while %EE remained unaffected. The sustained-release behaviour of CAE from all niosomes was under a diffusion controlled mechanism. Asiaticoside, a relatively polar compound from CAE-Nio-HA could penetrate through the stratum corneum and dermis in a larger amount than from CAE-Nio and CAE solution. CAE-Nio-HA formulations showed good stability under low temperature (4 °C and 25 °C) for periods longer than 4 months. In conclusion, the developed Nio-HA is a promising delivery system for asiaticoside to enhanced dermal absorption, permeation and accumulation in viable epidermis and dermis layers. This system can also be applied to other hydrophilic natural active compounds.