Ocular kinetics of pefloxacin after intramuscular administration in albino and pigmented rabbits.

We determined the ocular kinetics of pefloxacin, a new fluoroquinolone, when administered by the intramuscular route to albino and pigmented rabbits. In serum of albino rabbits, the area under the concentration-time curve (AUC) for the experimental period was 31.4 +/- 1.07 micrograms.h/ml (mean +/- standard deviation); the AUCs in the aqueous and vitreous humors were high (10.5 +/- 1.90 and 12.4 +/- 3.79 micrograms.h/ml, respectively). Pefloxacin was found in the avascular ocular tissues (30.15 +/- 3.79 micrograms.h/ml in the cornea and 6.98 +/- 1.06 micrograms.h/ml in the lens). In the vascularized tissues, the penetration ratio, defined as tissue AUC/serum AUC, was more than 1. The good intraocular diffusion of pefloxacin might be related to its low molecular weight and to its strong lipophilicity and could explain its clinical efficacy in the treatment of endophthalmitis. In pigmented rabbits, pefloxacin levels were high in the iris (1525 +/- 328 micrograms.h/ml, versus 40.2 +/- 5.08 micrograms.h/ml in albino rabbits) and chorioretina (2600 +/- 422 micrograms.h/ml, versus 48.3 +/- 7.52 micrograms.h/ml in albino rabbits), suggesting that it binds to the pigmentary apparatus.