Development and optimization of rizatriptan benzoate ethosomes

Abstract

Objective: The objective of this study was to assess the development of ethosomal drug delivery system for site-specific topical delivery of rizatriptan benzoate (RBZ) for sustained action. Methods: In the present study ethosomes were prepared using the cold method. The formulation was optimized using 33 full factorial designs. The lipid concentration (X1), ethanol concentration (X2) and stirring speed (X3) were selected as independent factors and the vesicle size (Y1) and % entrapment efficiency (Y2) were selected as dependent variables. Results: The equation of multiple regression revealed that there was no significant interaction among factors. The lipid concentration had a positive effect on vesicle size while ethanol concentration and stirring speed had a negative effect. For entrapment efficiency, all factors showed a positive effect while lipid concentrative found to be the main influencing factor. The formulation F4E459 (4% SPC, 45% v/v ethanol 900 RPM), which was characterized by optimum vesicle size (5.5 µm) and high entrapment efficiency (93.32%), was considered to be an optimal formulation. The scanning electron microscopy (SEM) results showed that RBZ ethosome have a smooth surface. The polydispersity index (PI) and zeta potential of the optimized formulation were found to be 0.493±0.021and-21.3 mV respectively. In vitro permeation through rat abdominal skin from the ethosomal gel followed Higuchi diffusion model over a period of 8 h. Conclusion: The results obtained in this research work clearly indicated a promising potential of ethosomal carrier system of RBZ for migraine treatment with a topical approach for sustained action.