[Intraocular penetration of DR-3355, a new quinolone derivative]

We studied the intraocular penetration of DR-3355, a new quinolone derivative in white mature rabbits. DR-3355 concentration in the aqueous humor reached the maximum, 1.06 micrograms/ml, at 2 hours after oral administration of 20 mg/kg in single dose. Six hours after it was 0.37 micrograms/ml. At 2 hours, the concentration ratio in the aqueous humor and serum was 23.3%. The pharmacokinetic parameters of DR-3355 levels in both of the aqueous humor and serum were: Cmax, 1.02 micrograms/ml and 4.56 micrograms/ml; Tmax, 1.42 hours and 1.47 hours; T 1/2, 0.96 hours and 1.57 hours; and AUC, 3.91 micrograms.hr/ml and 19.70 micrograms.hr/ml, respectively. At 2 hours after oral administration, the ocular tissue concentrations were 3.84-16.10 micrograms/g in the outer parts of the eye, and 0.70-13.52 micrograms/g or ml in the inner parts of the eye. Those concentrations decreased to about 1/2 to 1/32 in the outer parts, and 1/2 to 1/7 in the inner parts of the eye at 6 hours. Those ocular tissue concentrations of DR-3355 exceeded the MIC90 of the compound against various bacteria of ocular pathogens, such as Staphylococcus aureus, Staphylococcus epidermidis, Klebsiella pneumoniae and Serratia marcescens.