Nanoemulsion and Nanoemulsion Gel: A Novel Drug Delivery System

The current research work in all technical and biomedical fields is based on nanosize. Nanoemulsions are defined as transparent dispersions of oil and water stabilized as an interfacial film of surfactant and co-surfactant molecules having droplet size less than a micron. Nanoemulsions are thermodynamically stable dispersed system. Nanoemulsions were previously proved to be potential drug delivery tool for ocular, pulmonary, nasal, vaginal, and parental. In recent times, they have shown promising potential as transdermal drug delivery in delivering drug across the skin than other conventional transdermal delivery system. Nanoemulsions can be prepared by high-pressure homogenization, microfludization, ultrasonication and phase inversion method.Incorporating the preparation of nanoemulsion with hydrogel matrix to produce nanoemulgel exhibited by the two separate systems that forming it. Nanoemulgel possesses the properties of thixotropic, non-greasy, effortlessly spreadable, easily be removed, emollient, not staining, soluble in water, longer shelf life, bio-friendly, translucent and agreeable appearance. To enhance the solubility and permeability of poorly water soluble Valdecoxib, Nanoemulsion gel was formulated for the treatment of rheumatoid arthritis. Among the oils, surfactants and co-surfactants elainic acid, tween80 and ethanol were selected as they showed maximum solubility to Valdecoxib. The pseudo ternary phase-diagrams was constructed to find optimal concentration that provided the highest drug loading. The prepared Nanoemulsions were subjected trough thermodynamic stability testing.The droplet size, scanning electron microscopy (SEM) and zeta-potential were investigated.The optimized formulation of Nanoemusion NE2 which was showing 87.63% drug release was incorporated into polymeric gel of Carbopol940 for convenient application and evaluated for viscosity, PH, in-vitro permeations studies, skin irritation test and anti-inflammatory activity. The in-vitro skin permeations profile of optimized formulation was compared with normal Valdecoxib gel and Nanoemulsiongel NG2.The significant increase in permeability ratio (Kp), flux (Jss) and enhancement ratio (Er) was observed.The anti-inflammatory effect of formulation NG2 showed significant increase 72% inhibition effect in 24hrs when compared to Valdecoxib gel on Carrgeenan induced paw edema in rats. The results suggested that Nanoemulsion gels are potential vehicles for improved transdermal delivery of Valdecoxib.