Miller Table 6 Comparative MIC50s, MIC90s, and calculated pharmacodynamic indices for moxiﬂoxacin and gatiﬂoxacin for coagulase- negative staphylococci versus reported aqueous concentrations Drug Source Cmax Calculated MIC50 MIC50 MIC/MPC target value Moxiﬂoxacin Aqueous Gatiﬂoxacin Aqueous 0.38 ± 0.32 0.88 ± 0.88 1.31 ± 0.46 1.55 ± 0.86 1.61 ± 0.71 1.80 ±1.25 1.86 ± 0.23 2.16 ± 1.12 2.28 ± 1.23 0.19 ± 0.23 0.48 ± 0.34 0.63 ± 0.30 0.74 ± 0.66 0.82 ± 0.31 0.91 ± 0.54 0.94 ± 0.15 0.038 0.088 0.131 0.155 0.161 0.180 0.186 0.216 0.228 0.019 0.048 0.063 0.074 0.082 0.091 0.094 (Mather et al 2002) 0.05 (FQS) 2.5 (FQR) (Miller et al 2006) 0.09 0.09 (FQS) 2.0 (FQR) 0.19 MIC90 4 4 Derived from Mather et al (2002), Miller and Flynn (2006). Abbreviations: MIC90, concentration that inhibits 90% of isolates tested; MIC50, concentration that inhibits 50% of isolates tested; FQS, ﬂuoroquinolone sensitive; FQR, ﬂuroquinolone resistant. rather than the MIC90 was used. The ratio for moxiﬂoxacin using the MIC50 was 2.2 μg/mL vs 0.83 μg/mL for gatiﬂoxa- cin and 0.67 μg/mL for vancomycin. Clinical efﬁcacy No clinical trials have been conducted evaluating moxi- ﬂoxacin vs. nonﬂuroquinolone antibiotics for the treatment of keratitis and or endophthalmitis. In two pre-marketing, randomized, double-masked, multi-centered, controlled clinical trials to assess, safety and efﬁcacy of moxiﬂoxacin for the treatment of bacterial conjunctivitis, clinical cures were documented in 66%–69% of patients by day 4. Micro- biological eradication occurred in 84%–94% of the patients. Patients were dosed 3 times a day for 4 days. Age groups ranged from 2 to 92. No adverse events were reported in this group (Alfonso and Crider 2005). Deramo and colleagues reported no signiﬁcant difference in the rate of endophthalmitis using 4 times a day dosing of moxiﬂoxacin or gatiﬂoxacin pre- and post-operative compared to established endophthalmitis infection rates. In a retrospective, multicentered review of 20,013 patients from 9 cataract centers across 7 states, the overall rate of endophthalmitis following cataract surgery was 0.07%. The rate of postoperative endophthalmitis in the gatiﬂoxacin- treated group (81%, 16,209) was 0.06% (9 cases) and the rate for the moxiﬂoxacin-treated group (19%, 3804) was 86 0.1% (5 cases). The difference was not signiﬁcant (p = 0.11, nor was this rate lower than the earlier study by Miller et al using clear corneal phacoemulsiﬁcation (Miller et al 2005; Deramo et al 2006). Safety and biocompatibility Reported adverse reactions with 0.5% moxiﬂoxacin hydro- chloride ophthalmic solution administration have included: conjunctivitis, keratitis, decreased visual acuity, ocular hyperemia, dry eye, itching, subconjunctival hemorrhage, and tearing (Alcon Laboratories package insert) (Hariprasad et al 2005). Other infrequent ocular adverse events reported for the ﬂuoroquinolones as a class include chemosis, eyelid edema, and punctuate epithelial keratitis (Mah 2004). In vitro and animals studies have demonstrated a concen- tration dependent toxicity in studies of corneal epithelial cell migration and or proliferation, key components in corneal wound healing (Mallari et al 2001; Donnenfeld et al 2004; Kovoor et al 2004; Burka et al 2005; Durrie and Trattler 2005; McGee et al 2005; Robertson et al 2005; Solomon et al 2005; Donaldson et al 2006; Kaufman et al 2006; Ly et al 2006; Matsumoto et al 2006; McDermott and Wheater 2006; Stern et al 2006; Walter and Tyler 2006). Matsumoto and colleagues reported low and equivo- cal cell migration inhibition scores for moxiﬂoxacin and gatifloxacin versus ciprofloxacin at low concentrations Clinical Ophthalmology 2008:2(1)