Formulation and Evaluation of Liposomes for Transdermal Delivery of Celecoxib

BACKGROUND: Celecoxib is a selective cyclo-oxygenase-2 inhibitor recommended orally to treat arthritis and osteoarthritis. It is a highly lipophilic, poorly soluble drug with oral bioavailability of around 40%. Long term oral administration of celecoxib causes serious gastrointestinal side effects. OBJECTIVES: The current study aimed to assess the skin permeation of celecoxib by a transdermally applied liposomal formulation. MATERIALS AND METHODS: Liposomes were prepared by thin film method using soya lecithin and cholesterol. Physicochemical characteristics of the liposomes such as, particle size, drug encapsulation efficiency were determined. Also, drug release and in vitro skin permeability through rat skin were evaluated using Franz diffusion cells. RESULTS: The results showed that the maximum drug encapsulation efficiency was 43.24%. Drug release profile showed that 81.25% of the drugs released in the first 24 hours of the experiment. Fluxes (Jss), permeability coefficient (P), diffusivity coefficient (D) parameters of the optimum liposomal formulation were significantly higher than those of saturated aqueous solution of celecoxib. The decrease of lecithin increased values. Particle sizes of the formulations ranged from 0.117 to 1.123 µm. J(ss), D(app) and P parameters in L - 8 formulations were 29.18, 60.95, and 3.21 times higher than those of saturated water solution of celecoxib, respectively. The results of vesicles characterization indicated the potential application of celecoxib loaded liposome as carrier system. CONCLUSIONS: In conclusion, the components such as lecithin and cholesterol, and vortex time in liposomal formulations have an essential role in the physicochemical properties and celecoxib permeability through rat skin.