Ocular distribution of lomefloxacin 0.3% after a single instillation in the infected eye of pigmented rabbits

Ocular Pharmacokinetics

Although the fundamental concepts of pharmacokinetics remain the same, ocular pharmacokinetics has its own challenges due to the uniqueness of barrier properties posed by various ocular tissues and its growing complexity with different routes of ocular administration. A thorough understanding of the barrier nature will aid in tailoring a drug or its carrier's physicochemical properties to its advantage. In order to deliver the right payload of a drug at the target site, various approaches can be taken to leverage the pharmacokinetics that includes molecular design based on desirable physicochemical properties, formulation approaches, and alternative routes of administration. In this chapter, a brief overview of the barrier properties with respect to various routes of administration is presented along with the physicochemical properties that influence the pharmacokinetics of ocular drugs. Recent advances in ocular pharmacokinetics are discussed in addition to new perspectives in interpreting existing data.

Topical Lomefloxacin versus Topical Chloramphenicol in the Treatment of Acute Bacterial Conjunctivitis

We performed a prospective, randomised, investigator-masked and parallel-group study to compare topical lomefloxacin 0.3% instilled twice daily with topical chloramphenicol instilled five times daily in the treatment of acute bacterial conjunctivitis. 191 patients (lomefloxacin 96, chloramphenicol 95) were enrolled in this study with clinically diagnosed acute bacterial conjunctivitis. The two treatment groups were similar at baseline. The treatments were equally effective and significantly (p < 0.001) reduced the Cumulative Sum Score of the clinical signs and symptoms of bacterial conjunctivitis. At the end of the trial, there was no difference between the two treatments in the Cumulative Sum Score of signs and symptoms (p = 0.63), and the investigator (p = 0.28) and patients' (p = 0.50) assessments of the success of therapy. The two drugs were equally well tolerated locally, with no serious systemic or local adverse drug reactions reported in any study patient. Bacteriological confirmation of acute conjunctivitis was possible in 96 patients (lomefloxacin 47, chloramphenicol 49) out of the 191 enrolled. Both treatments significantly (p < 0.001) reduced the conjunctival bacterial colony count score with no difference (p = 0.12) between the two treatment groups. In conclusion, lomefloxacin 0.3% eye drops instilled twice daily were as effective and well tolerated as chloramphenicol 0.5% eye drops instilled 5 times daily in the treatment of acute bacterial conjunctivitis.

Lens concentration of ofloxacin and lomefloxacin in an experimental endophthalmitis model

Abstract.

BACKGROUND

Bacterial endophthalmitis is a serious complication of ocular surgery and penetrating trauma. The primary causative organisms are strains of Staphylococcus aureus and Staphylococcus epidermidis. Fluoroquinolones are widely used to treat endophthalmitis. There are a few studies on the penetration of fluoroquinolones into the lens in inflamed eyes. A literature search did not identify any data regarding penetration of topical ofloxacin into the lens in normal and inflamed eyes.

OBJECTIVE

The aim of this study was to determine the penetration of topical ofloxacin and lomefloxacin into the lens in a rabbit endophthalmitis model.

METHODS

New Zealand white rabbits were randomly divided into 2 groups. The left eyes were infected with an intravitreal inoculation of S aureus. The right eyes were used as a noninoculated control. Groups 1 and 2 received topical ofloxacin and lomefloxacin treatment, respectively, 24 hours after the inoculation. Two drops of the study drugs were instilled in the eyes every 30 minutes for 3 hours and then every 60 minutes for 3 hours. Lens samples were obtained 30 minutes after the last ofloxacin or lomefloxacin drops were administered. High-performance liquid chromatography was used to determine the fluoroquinolone concentration.

RESULTS

Ten rabbits were equally divided into the 2 treatment groups. There was no significant difference in mean (SD) lens concentrations between the control and inoculated eyes in either treatment group-ofloxacin (0.26 [0.32] μg/mL vs 0.11 [0.05] μg/mL, respectively) and lomefloxacin (0.50 [0.87] μg/mL vs 0.12 [0.08] μg/mL, respectively).

CONCLUSION

The results of this small experimental study found that topical ofloxacin and lomefloxacin can accumulate in the crystalline lens after installation. Inflammation did not affect the penetration of ofloxacin or lomefloxacin into the lens.

Bacterial keratitis: a prospective clinical and microbiological study

AIM

To define the clinical and microbiological profile of bacterial keratitis at the Jules Gonin Eye Hospital and to test the in vitro bacterial resistance.

METHODS

Patients presenting with bacterial keratitis were prospectively followed; clinical features (age, risk factors, visual acuity) and response to therapy were analysed. Bacteriological profile was determined and the sensitivity/resistance of isolated strains were tested towards 12 ocular antibiotics (NCCLS disc diffusion test).

RESULTS

85 consecutive patients (mean age 44.3 (SD 20.7) years) were prospectively enrolled from 1 March 1997 to 30 November 1998. The following risk factors were identified: contact lens wear, 36%; blepharitis, 21%; trauma, 20%; xerophthalmia, 15%; keratopathies, 8%; and eyelid abnormalities, 6%. The most commonly isolated bacteria were Staphylococcus epidermidis, 40%; Staphylococcus aureus, 22%; Streptococcus pneumoniae, 8%; others Streptococcus species, 5%; Pseudomonas, 9%; Moraxella and Serratia marcescens, 5% each; Bacillus, Corynebacterium, Alcaligenes xyloxidans, Morganella morganii, and Haemophilus influenza, 1% each. 1-15% of strains were resistant to fluoroquinolones, 13-22% to aminoglycosides, 37% to cefazolin, 18% to chloramphenicol, 54% to polymyxin B, 51% to fusidic acid, and 45% to bacitracin. Five of the 85 patients (5.8%) had a poor clinical outcome with a visual loss of one or more lines of visual acuity.

CONCLUSION

Fluoroquinolones appear to be the therapy of choice for bacterial keratitis, but, based upon these in vitro studies, some strains may be resistant.