Transfersomes--a novel vesicular carrier for enhanced transdermal delivery: development, characterization, and performance evaluation.

This work describes the use of a novel vesicular drug carrier system called transfersomes, which is composed of phospholipid, surfactant, and water for enhanced transdermal delivery. The transfersomal system was much more efficient at delivering a low and high molecular weight drug to the skin in terms of quantity and depth. In the present study transfersomes and liposomes were prepared by using dexamethasone as a model drug. The system was evaluated in vitro for vesicle shape and size, entrapment efficiency, degree of deformability, number of vesicles per cubic mm, and drug diffusion across the artificial membrane and rat skin. The effects of surfactant type, composition, charge, and concentration of surfactant were studied. The in vivo performance of selected formulation was evaluated by using a carrageenan-induced rat paw edema model. Fluorescence microscopy by using rhodamine-123 and 6-carboxyfluorescein as fluorescence probe was performed. The stability study was performed at 4 degrees C and 37 degrees C. An in vitro drug release study has shown a nearly zero order release of drug and no lag phase. The absence of lag phase in comparison to liposomes and ointment is attributed to the greater deformability, which may account for better skin permeability of transfersomes. In vivo studies of transfersomes showed better antiedema activity in comparison to liposomes and ointment, indicating better permeation through the penetration barrier of the skin. This was further confirmed through a fluorescence microscopy study. Finally, it may be concluded from the study that complex lipid molecules, transfersomes, can increase the transdermal flux, prolong the release, and improve the site specificity of bioactive molecules.