چکیده (انگلیسی):

The objective of the present research was to investigate the feasibility of using non-ionic
surfactant vesicles (niosomes) as carriers for the ophthalmic controlled delivery of a water soluble local
antibiotic; gentamicin sulphate. Niosomal formulations were prepared using various surfactants (Tween
60, Tween 80 or Brij 35), in the presence of cholesterol and a negative charge inducer dicetyl phosphate
(DCP) in different molar ratios and by employing a thin film hydration technique. The ability of these
vesicles to entrap the studied drug was evaluated by determining the entrapment efficiency %EE after
centrifugation and separation of the formed vesicles. Photomicroscopy and transmission electron
microscopy as well as particle size analysis were used to study the formation, morphology and size of
the drug loaded niosomes. Results showed a substantial change in the release rate and an alteration in
the %EE of gentamicin sulphate from niosomal formulations upon varying type of surfactant, cholesterol
content and presence or absence of DCP. In-vitro drug release results confirmed that niosomal
formulations have exhibited a high retention of gentamicin sulphate inside the vesicles such that their in
vitro release was slower compared to the drug solution. A preparation with 1:1:0.1 molar ratio of Tween
60, cholesterol and DCP gave the most advantageous entrapment (92.02%±1.43) and release results
(Q8h=66.29%±1.33) as compared to other compositions. Ocular irritancy test performed on albino
rabbits, showed no sign of irritation for all tested niosomal formulations.