Nanoemulsion-based film formulation for transdermal delivery of carvedilol

The objective of the present study was to investigate an oil in water nanoemulsion-loaded film as a transdermal delivery vehicle for the poorly-soluble drug, carvedilol. An optimized carvedilol-loaded nanoemulsion containing 10% w/w oil phase, 50% w/w surfactant: cosurfactant and 40% water was selected based on various parameters, including nanoemulsion mean droplet size, clarity, stability, and flowability, and this was then incorporated into the film. Carvedilol-loaded nanoemulsion films were prepared from 55% w/w hydroxypropyl methylcellulose (HPMC), 23% w/w chitosan, 5% w/w isopropanol and 17%w/w carvedilol-loaded nanoemulsion at a concentration of 25 mg/ml. Films were characterized for weight variation, thickness, moisture content and drug-excipient incompatibility. In addition, the in-vitro release of carvedilol from these films was determined using Franz diffusion cells and compared to control film prepared from aqueous blends containing 55% w/w HPMC, 23% w/w chitosan, 5% w/w isopropanol and 17%w/w polyethylene glycol (PEG 400) in which carvedilol was dissolved in PEG 400 at the same concentration of 25 mg/ml. Significant increases in the steady state flux (J(ss)), permeability coefficient (p) and flux enhancement ratio were observed in the nanoemulsion-based film (p < 0.05), when compared to the control film. These results suggest that nanoemulsion could be used as a potential vehicle for improved transdermal delivery of carvedilol.