The chain length and hydrophilic head of nonionic
surfactants affect entrapment efficiency,
such as stearyl chain C18 non-ionic surfactant
vesicles show higher entrapment efficiency
than lauryl chain C12 non-ionic surfactant
vesicles . The tween series surfactants bearing
a long alkyl chain and a large hydrophilic
moiety in the combination with cholesterol
at1:1 ratio have highest entrapment efficiency
for water soluble drugs27. HLB value of
surfactants affects entrapment efficiency, such
as HLB value of 14 to 17 is not suitable for
niosomes but HLB value of 8.6 has highest
entrapment efficiency and entrapment
efficiency decreases with decrease in HLB
value from 8.6 to 1.730