Intravitreal Liposome-Encapsulated Genfamicin in a Rabbit Model Prolonged Theropeuric Levels

The authors investigated the effect of Hposome encapsulation on the pharmacokinetics of gentamicin after intravitreal injection in albino rabbits, using immunofluorescent assay. Centamicin was encapsulated into liposomes of phosphatidylcholine, phosphatidic acid, and alpha-tocopherol. The final liposomal suspension contained gentamicin, 10 mg/ml, 95% encapsulated. One eye of each rabbit received an intravitreal injection (100 mg gentamicin per 0.1 ml) of either liposome-encapsulated gentamicin (LEG) or gentamicin in phosphate-buffered saline (G s ). Equilibrium dialysis separated free from encapsulated drug in vitreous samples. The peak free drug concentration was significantly less (P < .01, unpaired t-test) with LEG than with G s . Concentrations of free and total gentamicin were significantly greater (P < .05) with LEG than with G s at 24, 72,120, and 192 hr. LEG gave a twofold increase in area under the drug concentration time curve for total drug, and a 1.5-fold increase for free drug when compared to G s . Invest Ophthalmol Vi