Effect of Gatifloxacin Ophthalmic Solution 0.3% on Human Corneal Endothelial Cell Density and Aqueous Humor Gatifloxacin Concentration

Controlled transscleral drug delivery formulations to the eye: establishing new concepts and paradigms in ocular anti-inflammatory therapeutics and antibacterial prophylaxis

IMPORTANCE OF THE FIELD

The use of topical agents poses unique and challenging hurdles for drug delivery. Topical steroids effectively control ocular inflammation, but are associated with the well-recognized dilemma of patient compliance. Although administration of topical antimicrobials as prophylaxis is acceptable among ophthalmologists, this common practice has no sound evidence base. Developing a new antimicrobial agent or delivery strategy with enhanced penetration by considering the anatomical and physiological constraints exerted by the barriers of the eye is not a commonly perceived strategy. Exploiting the permeability of the sclera, subconjunctival routes may offer a promising alternative for enhanced drug delivery and tissue targeting.

AREA COVERED IN THIS REVIEW

Ocular drug delivery strategies were reviewed for ocular inflammation and infections clinically adopted for newer class of antimicrobials, which use a multipronged approach to limit risks of endophthalmitis.

WHAT THE READER WILL GAIN

The analysis substantiates a new transscleral drug delivery therapeutic approach for cataract surgery.

TAKE HOME MESSAGE

A new anti-inflammatory and anti-infective paradigm that frees the patient from the nuisance of topical therapeutics is introduced, opening a large investigative avenue for future improved therapies.

Penetration of Gatifloxacin Eye Drops into the Aqueous Humor in Humans

The authors topically administered gatifloxacin (GFLX) into the eye before cataract surgery and measured the concentrations of this agent to determine its penetration into aqueous humor. Seventy-seven patients with age-related cataracts who underwent cataract surgery were enrolled in this study. They received 0.3% GFLX ophthalmic solution 4 times at 30-min intervals, beginning 2 h before surgery. Aqueous humor was aspirated from the anterior chamber and assayed for GFLX concentration using high-performance liquid chromatography. The mean intraoperative GFLX concentration in aqueous humor was 0.485 +/- 0.328 microg/mL. GFLX level was 0.573 +/- 0.367 microg/mL in elderly patients, at least 70 years of age, and was significantly higher than that (0.322 +/- 0.135 microg/mL) in the patients less than 70 years old. This concentration was close to or higher than the minimum inhibitory concentrations required to inhibit the growth of 90% of major pathogens of endophthalmitis (MIC90), such as Staphylococcus aureus, Streptococcus pneumoniae, and Enterococcus faecalis associated with poor prognosis, other than Staphylococcus epidermidis, Pseudomonas aeruginosa, and MRSA (methicillin-resistant S. aureus) in vitro. The GFLX concentrations found in aqueous humor samples were sufficient to kill bacteria other than S. epidermidis, P. aeruginosa, and MRSA in vitro.

[Fluoroquinolones in ophthalmology: indications and current use]

Fluoroquinolones are commonly used in ophthalmology, either for conjunctival infections or endophthalmitis. Use of these antibiotics requires good knowledge of the pharmacokinetic profile and adverse effects, and contraindications must be respected. Fluoroquinolones are useful in 2008 given their antibacterial spectrum, good ocular penetration, and the potential benefit of intravitreal injection.

Ocular Pharmacokinetics of Moxifloxacin After Topical Treatment of Animals and Humans

The ocular penetration and pharmacokinetics of moxifloxacin in comparison to other fluoroquinolones (ofloxacin, ciprofloxacin, gatifloxacin, norfloxacin, levofloxacin, and lomefloxacin) have been determined by in vitro and ex vivo techniques, as well as in animal and human studies. This article reviews the original pharmacokinetics work performed by Alcon and other studies reported in the ocular fluoroquinolone literature. The results consistently demonstrate higher maximum concentrations for moxifloxacin relative to the other fluoroquinolones in ocular tissues with levels well above its minimum inhibitory concentrations for relevant ocular pathogens. This superior performance is due to the unique structure of moxifloxacin that combines high lipophilicity for enhanced corneal penetration with high aqueous solubility at physiological pH. The latter property creates a high concentration gradient at the tear film/corneal epithelial interface providing a driving force for better ocular penetration for moxifloxacin. In addition, the higher concentration of moxifloxacin in VIGAMOX (i.e., 0.5% vs. 0.3%) allows more antibiotic to be available to ocular tissues. It is clear from the array of studies summarized in this report that moxifloxacin penetrates ocular tissues better (two- to three-fold) than gatifloxacin, ciprofloxacin, ofloxacin, or levofloxacin. This consistent, enhanced penetration of topical moxifloxacin offers powerful advantages for ophthalmic therapy.