A surfactant used for preparation of niosomes
must have a hydrophilic head and
hydrophobic tail. The hydrophobic tail may
consist of one or two alkyl or perfluoroalkyl
groups or in some cases a single steroidal
group19.
The ether type surfactants with single chain
alkyl as hydrophobic tail is more toxic than
corresponding dialkylether chain .The ester
type surfactants are chemically less stable than
ether type surfactants and the former is less
toxic than the latter due to ester-linked
surfactant degraded by esterases to
triglycerides and fatty acid in vivo20