Elastic liposomal formulation for sustained delivery of antimigraine drug: In vitro characterization and biological evaluation

The aim of this study was to prepare and characterize a topical formulation for sustained delivery of rizatriptan. Elastic liposomal formulation of rizatriptan was prepared and characterized for different characteristics by evaluating in vitro and in vivo parameters. The in vivo performance of optimized formulation was evaluated for antimigraine activity in mice using morphine withdrawal-induced hyperalgesia. The in vitro skin permeation study across rat skin suggested carrier-mediated transdermal permeation for different elastic liposomal formulation to range between 18.1 +/- 0.6 and 42.7 +/- 2.3 mu g/h/cm(2), which was approximately 8-19 times higher than that obtained using drug solution. The amount of drug deposited was 10-fold higher for elastic liposome (39.9 +/- 3.2%) than using drug solution (3.8 +/- 1%); similarly the biological activity of optimized elastic liposome formulation was found to be threefold higher than the drug solution. On the basis of the results, it can be concluded that the elastic liposomal formulation provided sustained action of rizatriptan due to depot formation in the deeper layer of skin.