Effect of Lyophilization on the Size and Polydispersity of Unilamellar and Multilamellar Liposomes

Abstract

With the emergence of drug delivery systems, liposome's attracted many attentions as drug and gene delivery vehicles. In this regard, long-term stability of liposomes becomes important in the clinical use of these particles and their success in the market of therapeutics. Lyophilisation is one of the most common methods for preservation of liposome nanoparticles. This process may change some key properties of particles such as size and polydispersity. Hence, in this article we investigated the effects of lyophilization process on these two parameters. A multilamellar liposomal formulation of DOTAP/DOPE/Cholesterol was fabricated through modified lipid film hydration method while extrusion was employed to obtain unilamellar ones. Lyophilization was performed in the presence of sucrose used as the cryoprotectant. The results show that after lyophilization, the mean particle size of both multilamellar and unilamellar vesicles had no significant change (p > 0.1) in contrast to poly dispersity index (p < 0.05