Delivery of gatifloxacin using microemulsion as vehicle: formulation, evaluation, transcorneal permeation and aqueous humor drug determination

The successful ophthalmic delivery system is reliant on the diminution in the precorneal loss of drugs by increasing the corneal contact time and increasing the transcorneal permeability, which may enhance the bioavailability of drug to the eyes. The objective of this investigation was to develop and evaluate the potential of microemulsions of gatifloxacin with respect to the conventional eye drops of gatifloxacin. Oil-in-water microemulsions were prepared with different concentrations of oil, surfactant and co-surfactant using aqueous titration method. All formulations showed circular shape droplets, displayed an average droplet size ranged between 51 and 74nm and absolute zeta potential values ranged from 15 to 24mV, with optimum physicochemical characteristics suitable for eye. The optimized microemulsion possessed good stability, showed greater adherence to corneal surface and good permeation of gatifloxacin in the anterior chamber of the eye, resulting in a twofold increase in gatifloxacin concentration than the conventional dosage form. Hence, the optimized microemulsions showed increased intraocular penetration and enhance ocular bioavailability of gatifloxacin.