The intraocular penetration and pharmacokinetio analysis of norfloxacin were dbserved.The concentration of norfloxacin was measured successflly by high performance liquid chromatography (HPLC) after topically applying 0.3% norfloxacin eyedrops to rabbit eyes. The results showed that norfloxacin could rapidly penetrate into rabbit ocular tissues. The concentration order was cornea

iris-ciliary body

lens

vitreous body

aqueous humour. Among all tissues concentration of norf loxacin in cornea was the highest. The permeability of norfloxacin in cornea epithelial barrier(Kep)was 2.91 10-’.The half-life ( Tl/2)of tha tissue concentration in lacritnal fluid

cornea

aqueous humour

iris-ciliary body

lens and vitreous body was 2.99h

0.69h

1.82h

1.18h

1.23h and O.Slh

respectively. The peak conc-entration(Cmax) of norfloxacin in the tissues was 9.18p.g/g in cornea

0.35ng/ml in aqueous humour

5.l7|ig/g in iris-ciliary body

1.36|ig/g in lens and 0.59ug/ml in vitreous. The experiment indicates that norfloxacin can maintain higher concentration in lacrimal fluid and cornea. Therefore

it is the first choice of drugs for treatment of superficial ocular infection