Effect of terpene liposomes on the transdermal delivery of hydrophobic model drug, nimesulide: Characterization, stability and in vitro skin permeation

Abstract

This study evaluates the ability of the terpenes incorporated in liposomes on the in vitro skin delivery of hydrophobic model drug, nimesulide (NE). To this purpose, so-called terpene liposomes (TPs), which are composed of phospholipid and three types of terpene, citral, limonene and cineole. The obtained formulations were characterized in terms of size distribution, zeta potential and morphology. The efficiency of TPs on skin delivery of NE was studied using in vitro Franz diffusion cells and abdominal rat skin in comparison with conventional liposomes and ethanolic solutions of NE. Results showed that all the used TPs had spherical structures with negative zeta potential, low polydispersity (PDI < 0.2), nanometric size range (z-average no more than 150 nm). TPs improved the entrapment efficiency (EE%) and gave good physical stability. In vitro skin permeation data showed that TPs were able to give a significant improvement of NE permeation through the rat skin in comparison with conventional liposomes and drug solution. Moreover, the TPs prepared with limonene were also able to deliver a higher amount of NE than the other formulation, thus suggesting that NE delivery to the skin was strictly correlated to type of terpenes incorporated liposomes.