Non-Ionic Surfactant Vesicles (Niosomes) as New Drug Delivery Systems

Introduction

There are versatile lists of amphiphilic compounds for production of lipid vesicles which on the basis of used amphiphiles or structural compounds, different nomenclature has been used such as liposomes (Kaminskas et al. 2012), niosomes (Moazeni et al. 2010; Akbari et al. 2013), ufasomes (Patel et al. 2011), ethosomes (Liu et al. 2012), eliposomes (Lattin et al. 2012) and so on. In lipid vesicular systems, polar headgroups of amphiphilic molecules are oriented into aqueous compartments and their lipophilic parts form bilayer membranes. Niosomes are bilayer vesicles composed mainly of hydrated non-ionic surfactants in addition to, in many cases, cholesterol (CHOL) or its derivatives (Pardakhty and Moazeni 2013). Cosmetic industry was the place for the first account of niosome production (Handjani‐Vila et Al. 1979) after which a large number of niosome applications in drug, vaccine and gene delivery have been explored. While most niosomes are in the nano or sub-micron (colloidal) size range, not many authors used the “nanoniosome” or “nanovesicle” titles in their published articles due to introduction the new nanotechnology related phrases during the few recent years. Niosomes are capable to encapsulate both hydrophilic and lipophilic substances which the first ones usually are entrapped in vesicular aqueous core or adsorbed on the bilayer surfaces, and lyophobic molecules are encapsulated by their partitioning into the lipophilic domain of the bilayers. Incorporation of charged molecules into non-ionic surfactant vesicles forms charged or hybrid niosomes (Sennato et al. 2008). Vesicles can be also prepared from the mixed cationic and anionic surfactant systems such as cetyltrimethylammonium bromide and sodium lauryl sulfate (CTAB-SLS) (Aiello et al. 2010). These types of vesicles are presented as “cat-anionic” or “catanionic” vesicles. Catanionic vesicles can also be formed from electrostatic interaction between an ionized drug, such as diclofenac (Zhao et al. 2013) or alprenolol (Dew et al. 2012) and a positively/negatively charged surfactant.

Non-ionic surfactants have more chemical stability against oxidation and are less thermo-labile in comparison to phospholipids, the main constituent of liposomes (Fang et al. 2001; Tarekegn et al. 2010)thus less significant care in handling and storage are needed. Furthermore, greater versatility and lower cost make this type of vesicles more attractive in drug, gene and vaccine delivery (Florence 1993). From the pharmaceutical manufacturing stand of view the superiority of niosomes is simple methods required for industrialized and large–scale production of them without the use of pharmaceutically unacceptable solvents (Sahin 2007). In this chapter the most important aspects of niosomes and drug delivery potentials will be reviewed. Application of niosomes as gene or vaccine delivery tools will not discussed in this chapter.

Figure 1.

α,ω-trioxyethylene-bis (sodium 2-dodecyloxy-propylenesulfonate), an anionic gemini surfactant, used for preparation of niosomes

Muzzalupo et al. 2008.