Background: Conventional dosage forms of neomycin sulphate suffer from different
drawbacks like spillage, poor penetration, low bioavailability, etc. In situ ophthalmic
gel can overcome these problems by improving bioavailability, decreasing spillage and diminish
the need for recurrent application. Thus, the aim of the present work was to prepare
and evaluate in situ ophthalmic gel of neomycin sulphate for sustained ocular delivery.
Method: Two polymers, sodium alginate (0.2-0.7%) and HPMC K4M, were used in different
concentrations for the preparation of neomycin sulphate insitu gel. The prepared gel
was subjected for rheological study, in vitro gelation, drug release study, antimicrobial
study by disk diffusion method and others.
Result: All formulations were found to be transparent and clear; pH of the formulations
was within 6.8 to 6.9; drug content was found within 92-98% in all optimized in situ gelling
systems. Viscosity of all formulations decreased as the shear rate increased, which indicated
the character of pseudoplastic fluid. Optimized formulations F6 (0.5% Sodium alginate
and HPMC K4M 1.5%), F7 (0.3% Sodium alginate and HPMC K4M 1.7%) and F8
(0.4% sodium alginate and HPMC K4M 2%) were liquid before instillation to the eye and
underwent rapid gelation upon instillation to the eye. In vitro release through diffusion cell
using cellophane membrane for 8 hours revealed sustained release of the drug from sodium
alginate polymeric network over 6 hours. Study of antimicrobial efficacy using Pseudomonas
aeruginosa for 24 hours showed all formulations to have effective antimicrobial action.
Stability study for 6 months had revealed no changes in visual appearance, clarity, pH
and % drug content.
Conclusion: Hence, from the above results we can conclude that in situ ophthalmic gels of
neomycin sulphate can be a good option for the treatment of various bacterial eye infections.